Servo Magazine 06-2017

D940/941TW Operating Voltage Range No Load Speed Range Peak Torque Range Maximum Current Draw Dimensions Weight

D945/946TW

D950/951TW

D980TW

4.8V ~ 7.4V

4.8V ~ 7.4V

4.8V ~ 7.4V

4.8V ~ 7.4V

0.11 ~ 0.07 Sec @ 60°

0.16 ~ 0.10 Sec @ 60°

0.23 ~ 0.14 Sec @ 60°

0.28 ~ 0.17 Sec @ 60°

10.0 ~ 16.5 kg-cm 139 ~ 229 oz-in

14.0 ~ 23.0 kg-cm 194 ~ 319 oz-in

21.0 ~ 35.0 kg-cm 292 ~ 486 oz-in

26.0 ~ 44.0 kg-cm 361 ~ 611 oz-in

3700 ~ 6200mA

4800 ~ 6200mA

40.0 x 20.0 x 38.0mm 1.57 x 0.79 x 1.50 in

43.8 x 22.4 x 40.0mm 1.72 x 0.88 x 1.57 in

68g / 2.40 oz

78.2g / 2.76 oz

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s etail ore d ng, For m bscribi n u on s our ad o see ge 19. Pa

06.2017 VOL. 15 NO. 6

Subscription Information SERVO Magazine — PO Box 15277 North Hollywood, CA 91615-9218 Call 877-525-2539 or go to www.servomagazine.com Subscribe • Gift • Renewal • Change of Info

Columns 08 Robytes

PAGE 58

by Jeff and Jenn Eckert

Stimulating Robot Tidbits • Could Cause Insomnia • New Security Concerns • Seen a Ghost? • Dinner is Served • Unseen Bot Wars

12 Ask Mr. Roboto with Eric Ostendorff

Topics discussed this month include: building stable LEGO configurations; getting started in combat robots; the right type of battery to use with experimental carpet rovers; swarm behavior; the rule of thumb for choosing servo strength; and building a bartending robot.

58 Then and Now by Tom Carroll

Human/Robot Interaction with the Elderly The design of companion robots to interact with and assist elderly persons in their daily living has been one of the many goals of roboticists for decades. Read about the difficulties that robot designers have had to and will have to overcome to have a viable home assistant robot for the elderly.

The Combat Zone 20 Robot Wars, Girls, and Glitter 22 EVENT REPORT: Motorama 2017

Departments 18 Bots in Brief • Lord of the Wire Jungle • Long Neck Robot • Tea Time

06 Mind/Iron

Wanted: Robotics Experimentalists

07 Events Calendar 13 Showcase

16 17 65 66

New Products RoboLinks Advertiser’s Index SERVO Webstore

SERVO Magazine (ISSN 1546-0592/CDN Pub Agree#40702530) is published monthly for $26.95 per year by T & L Publications, Inc., 430 Princeland Court, Corona, CA 92879. PERIODICALS POSTAGE PAID AT CORONA, CA AND AT ADDITIONAL ENTRY MAILING OFFICES. POSTMASTER: Send address changes to SERVO Magazine, P.O. Box 15277, North Hollywood, CA 91615 or Station A, P.O. Box 54, Windsor ON N9A 6J5; [email protected]

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In This Issue ... 25 Dirty Jobs for Robots in the Tank by Holden Berry Some robots don’t get the iPhone treatment or a red carpet rollout, but that doesn’t mean they’re any less important. These are the robots doing dirty jobs that are making workplaces cleaner and safer, and they deserve to be honored too! Case in point: Scantron Robotics’ tank cleaning bot. PAGE 25

28 Hacking an RC Car with the Mentor’s Friend by Dane Weston This article introduces the Amigo (a Propeller based retro computer that emulates those early 1980’s classic computers you hooked to a TV and programmed in BASIC) to SERVO readers and presents a simple computer-controlled hardware project (hacking a toy RC car) that you and a budding roboticist can build and explore together.

PAGE 28

34 Animatronics for the Do-It-Yourselfer by Steve Koci Putting On a Face What good is a fully functioning mechanical character without a face? For me, the most important and difficult exposed surfaces dilemma is how to complete the head. Hopefully, this article will provide the necessary guidance for you to create your own characters.

40 An Arduino Controlled Robot Arm by Ricardo Caja Calleja After completing an online course on robotics, I decided to create a robot arm that I could use as a platform to test all the theory that had been covered and experiment with new ideas.

47 The Gortinator

PAGE 40

by Carol Lynn Hazlett See how to build a two-legged walking robot made from PITSCO/TETRIX MAX parts.

52 The Multi-Rotor Hobbyist by John Leeman Brushless Motor Basics Get an introduction to the fundamental workings of a brushless DC motor and learn how to select the right motor for your next project. SERVO 06.2017

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Mind / Iron by Bryan Bergeron, Editor ª

Wanted: Robotics Experimentalists — No Experience Necessary (or Desired) t seems that every few months there’s renewed talk of robots taking over one job or another. Included are the usual suspects in the dull, dirty, and dangerous categories — from mining, search and rescue, and manufacturing to fire fighting — as well as the more nuanced areas of robotic surgery, self-driving helicopters and cars, and semi-autonomous planet rovers. Despite all the talk and an occasional highly visible demo, there hasn’t been much in the way of deliverables. So, what’s the problem? Technology is, of course, one limitation, as is funding for full development and deployment. But there’s more. There’s a lack of domain-specific leadership to champion the technology that will eventually replace human workers. Not surprisingly, these champions rarely come from within the ranks. Think about it. Why would a factory line worker by day and robotics experimentalist by night work to build a robotic system to put himself and everyone he works with out of a job? Granted, the experimentalist might have his or her goals set on leaving the day job, but then there’s the issue of being too close to the job. That is, it’s often the case that someone with years of experience at performing a task a specific way can’t see how to improve the process. Simply automating a poor process is a recipe for failure. So, what’s the solution? Become the outsider that brings robotics expertise with a fresh take on the problem and no internal political complications. I’m not suggesting that as a robotics experimentalist you should gloss over the problem area and

I

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shoot from the hip when it comes to robotics. You will need to study the problem domain intensely and bring your other work experiences to bear in formulating a practical roboticsbased solution. You’ll also have to interview workers and management. Present your solution to the stakeholders with something to gain from your invention — whether it’s the factory owner, insurance provider, mine operator, or city hall. Will you make enemies in the process? Sure, if you’re successful. Will you change the world? Definitely! That’s the point, isn’t it? SV

Did You Know ...

Preferred Subscribers get access to all digital back issues of

SERVO Magazine for free? Call for details

1-877525-2539 or go to

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FOR THE ROBOT INNOVATOR

ERVO

Published Monthly By T & L Publications, Inc. 430 Princeland Ct., Corona, CA 92879-1300 (951) 371-8497 FAX (951) 371-3052 Webstore Only 1-800-783-4624 www.servomagazine.com Subscriptions Toll Free 1-877-525-2539 Outside US 1-818-487-4545 P.O. Box 15277, N. Hollywood, CA 91615 PUBLISHER Larry Lemieux [email protected] ASSOCIATE PUBLISHER/ ADVERTISING SALES Robin Lemieux [email protected] EDITOR Bryan Bergeron [email protected] VP of OPERATIONS Vern Graner [email protected] CONTRIBUTING EDITORS Tom Carroll Kevin Berry R. Steven Rainwater Eric Ostendorff Steve Koci John Leeman Jeff Eckert Jenn Eckert Holden Berry Dane Weston Ricardo Caja Calleja Carol Hazlett James Baker Nate Franklin CIRCULATION DEPARTMENT [email protected] WEBSTORE MARKETING COVER GRAPHICS Brian Kirkpatrick [email protected] WEBSTORE MANAGER/ PRODUCTION Sean Lemieux [email protected] ADMINISTRATIVE STAFF Re Gandara Copyright 2017 by T & L Publications, Inc. All Rights Reserved All advertising is subject to publisher’s approval. We are not responsible for mistakes, misprints, or typographical errors. SERVO Magazine assumes no responsibility for the availability or condition of advertised items or for the honesty of the advertiser. The publisher makes no claims for the legality of any item advertised in SERVO. This is the sole responsibility of the advertiser. Advertisers and their agencies agree to indemnify and protect the publisher from any and all claims, action, or expense arising from advertising placed in SERVO. Please send all editorial correspondence, UPS, overnight mail, and artwork to: 430 Princeland Court, Corona, CA 92879.

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EVENTS JUNE 1-3

RoboFest St. Pete Beach Community Center St. Pete Beach, FL Events include Bottle Sumo, Vcc, Game, GRAF, and UMC. http://robofest.net

23-25

MATE ROV Competition Long Beach City College, Long Beach, FL Student underwater robot challenge. www.marinetech.org

24

Clash of the Bots Schiele Museum, Gastonia, NC Events include bot hockey and RC vehicle combat. www.carolinacombat.com

1-3

University Rover Challenge Mars Desert Research Station, Hanksville, UT Student teams build rovers for an extreme desert environment. http://urc.marssociety.org

24-25

International Autonomous Robot Contest E3 Civic High School, San Diego, CA Autonomous robots must navigate around fixed obstacles. http://iaroc.org

2-5

AUVS International Ground Robotics Competition Rochester, MI Autonomous ground robots must navigate an outdoor obstacle course within a prescribed time and speed limits. www.igvc.org

24-25

Robotic Day Prague, Czech Republic Events include Bear Rescue, Ketchup House, Line Following, Mini Sumo, and RoboCarts. www.roboticday.org

3

Concurso De Robótica Aguilar Tapachula, Chiapas, Mexico Events include Line Following, Labyrinth Solving, Mini Sumo, Cockerel, and Robot Arm Challenge. http://electronica-aguilar.blogspot.com

3

Pobot Junior Cup Sophia-Antipolic, France Waste collection robot challenge. www.pobot.org

17-18

Seattle Bot Battles Seattle Center Armory Seattle, WA RC vehicle combat. www.western alliedrobotics.com

19-23

European Robotics Hackathon Sonnenweg 1, 3435 Zwentendorf an der Donau Austria Robot hackathon at inactive nuclear reactor site. http://enrich.europeanrobotics.eu

HBRC Challenge and BotLuck Dinner Nothing but the best part of the meeting: All Show-and-Tell featuring RoboMagellan Trials, the Original TABLEBot Challenge, FloorBot Challenge, The A-Mazing Line Maze Challenge, Robot Dance Party, and Run-what-ya-brung. What: HBRC Challenge Where: 1200 Crittenden Ln., Mountain View, CA 94043 When: May 31st, 6 pm - 10 pm HomeBrew Robotics Club • www.hbrobotics.org

Two days of shop talk with experts, hands-on training, and CNC exploration. Plus, meet BattleBots champ, Ray Billings, and Tombstone! Friday

Saturday

HANDS-ON WORKSHOPS

CNC EXHIBITIONS

TORMACHTECHDAYS.COM SERVO 06.2017

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Robytes by Jeff and Jenn Eckert Could Cause Insomnia Boston Dynamics (bostondynamics.com) has been designing robots that are big, strong, and usually horrifying since 1992; most notably, the BigDog robotic pack mule designed for the US military. The tradition of terror continues with their latest offering called “Handle,” which even company founder, Marc Raibert called “nightmare-inducing.” As a two-legged wheeled machine with only 10 actuated joints, it seems like a relatively simple concept. However, the massive (6 ft, 5 in) bot can travel at 9 mph (14.5 kph), jump as high as 4 ft (1.2 m), and roll down a flight of stairs while maintaining its balance. Plus, the batterypowered machine has a range of about 15 mi (24 km) between charges. Handle has two arms mounted in its hip region that can lift and carry as much as 100 lb (45 kg), so it appears destined for factory or warehouse work. However, it is still in the development stage, as the company needs to add

New Security Concerns Whereas the computer industry has been dealing with security issues for many years, it appears that the auto industry has only recently begun to consider the looming problem of hackers wreaking havoc with driverless cars, and manufacturers of IoT (Internet of Things) devices may be giving scant attention to security issues. Likewise, a recent analysis of robots used in homes as well as

Bots using the V-Sido OS (such as Kuratas) may be vulnerable.

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SERVO 06.2017

Handle: Boston Dynamics’ latest offering.

some refinements to make sure human coworkers won’t be crushed, decapitated, or otherwise inconvenienced during its operation. For a slew of videos, just search YouTube for “Introducing Handle.”

commercial and industrial settings has concluded that security is dangerously lax in those areas. In conducting related research, security firm IOActive (www.ioactive.com) tested a variety of software components used in a wide range of robotic devices and discovered that most had such issues as insecure communications, ineffective authentication and authorization procedures, weak cryptography, and vulnerable open source frameworks and libraries. According to the report, “We’re already experiencing some of the consequences of substantial cybersecurity problems with IoT devices that are impacting the Internet, companies and commerce, and individual consumers alike. Cybersecurity problems in robots could have a much greater impact. When you think of robots as computers with arms, legs, or wheels, they become kinetic IoT devices that if hacked can pose new serious threats we have never encountered before.” It’s always wise to have a little skepticism when someone tells you that you have a problem and then coincidentally happens to have the solution in his briefcase, and IOActive is in the business of providing information security services. However, the report makes a lot of sense, so you might want to download the free PDF from the company’s homepage.

Eckert - Robytes - Jun 17_Robytes - Sep 15.qxd 5/2/2017 3:46 AM Page 9

Go to www.servomagazine.com/index.php/magazine/issue/2017/06 to comment on these topics.

Seen a Ghost? One of the new kids in robot town is Ghost Robotics (www.ghostrobotics.io), founded in 2015 with support from the University of Pennsylvania and PCI Ventures. The overall company strategy is to commercialize legged robots by reducing their complexity and boosting their durability. Their first product is the Ghost Minitaur, described as “a medium-sized fast, lightweight, and dynamic directdrive legged robot platform for research and development of commercial unmanned ground vehicles (UGVs), advanced gait and locomotion research, and machine learning and training applications.” Minitaur features high torque brushless Outrunner motors (i.e., motors that spin their outer shells around their windings) and a specialized leg design that allows it to run, jump, and climb over rough terrain.

Minitaur climbs a chain-link fence.

Minitaur prepares to leap a 22 in (0.55 m) gap.

According to Ghost, “Minitaur’s unique leg design and custom motor controllers let our motors behave like springs, and our directdrive motors can be programmed to mimic spring-damper systems with 100 percent software tunable active compliance.” The company’s slogan — “Robots that feel the world” — refers to a direct-drive torque estimation feature that means Minitaurs “are quick to react and know exactly how hard they’re pushing. Our direct-drive motors have excellent actuator transparency, meaning they can easily conform to the environment when desired, but can also exert large torque when necessary.” Videos are, of course, accessible on YouTube; just search on “Ghost Minitaur.” If you like what you see, you can pick one up at a base price of $11,500.

Dinner is Served Much has been made of Amazon’s plan to deliver packages by drone, but the concept is still a bit speculative, given such hurdles as limited quadcopter ranges and payloads, FAA regulations, and kids with BB guns. A terrestrial alternative, however, has already been launched by a 2014 startup named (somewhat ironically) Starship Technologies (www.starship.xyz). Starship offers six-wheeled autonomous delivery vehicles that are designed to navigate urban sidewalks and bring things to your door. Each device weighs about 40 lb, moseys along at about 4 mph (6.4 kph), and can carry the equivalent of three shopping bags full of stuff. Equipped with cameras, tracking devices, and other instrumentation, the units have been successfully tested in 59 different cities and 16 countries, covering more than 16,000 miles (26,000 km) over a one year period. Starship already has signed agreements with two meal delivery companies that should have the units in operation by the time you read this. Postmates initially has fielded a fleet of five delivery bots in Washington, DC, and DoorDash has 10 of them running around Redwood City, CA, which is also the Starship US headquarters.

Starship delivery bot navigates a sidewalk in London.

The robots are designed to operate within a two to three mile radius and execute deliveries in about 15 to 30 minutes. For now, each bot is accompanied by a human who watches over the process and presumably chases away winos who try to steal your dinner. However, the bots will eventually work alone. All you have to do when one arrives at your door is use a button on the Starship app to unlock the hatch, and it’s bon appétit!

SERVO 06.2017

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When you think about battling robots, you usually picture mechanical devices slugging it out in an arena with lots of cheering spectators. However, it turns out that another type of “bots” (i.e., simple computer programs that crawl around the Internet performing repetitive operations) has been battling it out for years without anyone knowing about it. According to a research article published in the PLOS ONE technical journal (journals.plos.org/plosone), Wikipedia (www.wikipedia.org) employs some 2,065 bots to sift through its pages to identify and undo vandalism, enforce bans, check spelling, create interlanguage links, import content, identify copyright violations, and so on. Apparently, editing bots often disagree about spelling, terminology, etc., and many of Wikipedia’s bots ended up continuously correcting and recorrecting each other over periods of months to years. The authors believe that such conflicts were largely resolved in 2013 when Wikipedia started to provide inter-language links via its Wikidata knowledge base. Wikipedia is only one example, and the overall lesson is that the Internet “botosphere” is full of not only wellintentioned bots that perform desired tasks, but also malevolent social bots (such as those posing as humans on Twitter) that often coordinate their behavior in the form of botnets. The authors note, “Our research suggests that even relatively ‘dumb’ bots may give rise to complex interactions, and this carries important implications for Artificial Intelligence research. Understanding what affects bot-bot interactions is crucial for managing social media well, providing adequate cyber-security, and designing well functioning autonomous vehicles.” So, maybe Stephen Hawking is right about AI after all. SV

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Ask Mr. Roboto Tap into the sum of all human knowledge and get your questions answered here! From software algorithms to material selection, Mr. Roboto strives to meet you where you are — and what more would you expect from a complex service droid?

Q

. I’ve used my new LEGO MINDSTORMS to build a robot arm in the hopes of having it solve the famous “Tower of Hanoi” problem as a school project. Though I have the software part working, the arm itself seems to always come apart after just a few moves. Can you share any tricks for building stable LEGO configurations? Robert Tanner Montrose, CA

A

. You didn’t specify if you are using traditional LEGO bricks (friction fit) or the new girder/struts (snap fit, Figure 1). Either way, LEGO is a fantastic construction system. The consistent fit of their many pieces is achieved through incredible process and quality control throughout their manufacturing cycle. They are a role model in the industry. Unfortunately, what assembles easily also disassembles easily. On a long robot arm, the weight of the plastic parts is hardly negligible, and the longer the arm, the higher the static forces get. Dynamic forces (acceleration, bouncing) make the situation even worse. Connections can work themselves apart, and servo loads increase. It pays to build small and light to minimize weight, mass, and moment of inertia. Adding heavy bracing parts becomes a losing battle. Gluing the parts together for a permanent assembly is your best option. Cyanoacrylate (CA) is “forever” and bonds most materials together instantly, but takes some practice to use properly and neatly. CA comes in thick and thin types.

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SERVO 06.2017

Thin CA flows like water and often gets into places you don’t want. Thin CA can be used with baking soda to build strong fillets and ribs for strength. Solvent bonding works with styrene and ABS parts. Testor’s plastic model glue is available at most hobby shops. Acetone (finger nail polish remover) is another option to solvent bond styrenes, and is commonly and cheaply available. If you have a plastic supply store near you and some extra money, you can find Weld-On or Plastruct Weld solvents. These waterthin solvents can be applied to parts assembled in place using a small paint brush or squeeze bottle. Incidentally, I’m a huge fan of Towers of Hanoi robot arms. I have

Figure 1. LEGO arm.

by Eric Ostendorff Our resident expert on all things robotic is merely an email away.

[email protected]

built two by hacking kid’s robot claw toys. See my videos at https://www .youtube.com/watch?v=Z8lTSX4PHs and https://www. youtube.com/watch?v=Og0JPJ5HQ 4s. I cut my disks out of thick closedcell foam, which is lightweight, grippy, and slightly flexible.

Q

. I have been thinking about getting into combat robots but I’m not sure if I have the resources necessary to really have a chance at winning anything. Can you give me an idea as to how much money/time it takes to build an entry level combat robot that has a chance in the ring? Archie Chambers Oklahoma City, OK

Ostendorff - Mr Roboto - Jun 17_MrRoboto - Sep 15.qxd 5/2/2017 3:48 AM Page 13

Your robotic problems solved here.

To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index.php/magazine/issue/2017/06.

Figure 2. RoboGames.

A

. You are wise to plan ahead for combat robotics (Figure 2). It’s great fun for the spectators, and quite a resource drain for the builders — both in time and money. My friend, Mark and I were on the first season of Learning Channel’s “Robotica.” I learned that it’s easy to slap a working bot together, but making it impact-resistant, reliable, and battle ready takes 2-3 times as long. Testing is costly but essential. You’ll go through parts in testing, but driving the bot well is even more important than weapons or armor. For that reason, I’d suggest that you start small (smaller is usually cheaper and faster) and find an equally dedicated partner to share the load with. Winning teams often have a dedicated driver with lots of RC car experience, and one or more build/repair/schlep guys. Everybody knows about BattleBots™, and there are other venues as well. RoboGames (Pleasonton, CA; http://robo games.net) has combat events for many weight classes ranging from 340 lbs all the way down to one pound, with dozens of other robot contests/challenges too. Seattle’s Robothon (https://robothon.org) also has combat robotics and several other contests.

You already know that SERVO Magazine is a goldmine of information with several articles each month on combat robotics. Learn from these pros; they speak from experience. Many articles focus on upgrading last year’s robot based on key things learned during battle. You’ll want to read every article. It’s hard to quote numbers for cost and time; that will vary with your experience and expectations. In general, I would say manage your expectations and don’t expect to win your first time out. In fact, expect to lose and learn on the journey. Start early and allow plenty of time for testing, driving, and rebuilding. Estimate realistically how much time and money you’ll need at the start. Then, triple EVERYTHING.

Q

. I’m trying to settle on a battery technology for my experimental carpet roving robot. What do you use as criteria when choosing a battery type? Frank Bowens San Jose, CA

A

. From my experience, you have the optimum situation: indoors on flat carpeting. You can probably use a more or less SERVO 06.2017

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Ostendorff - Mr Roboto - Jun 17_MrRoboto - Sep 15.qxd 5/2/2017 3:48 AM Page 14

“standard” 2WD chassis using differential steering and front/rear casters. Wheels are very efficient and with no hills to climb, weight is not hyper critical. Nearly any battery chemistry should be viable (except alkaline cells, which should be banned immediately). Lithium-Ion and LiPo cells are all the tech rage now and will work fine in your application. They are lightweight with incredible energy density. Older battery technologies are also an option. Ni-Cad and NiMH cells are commonly available, and while heavier than lithium batteries, work fine. I can even make a case for heavy lead-acid SLA cells in the carpet rover you describe. The 6V and 12V types used in alarm systems can be found relatively cheap. While big and heavy, they are arguably the easiest to charge, so you could make a very simple twoconductor auto-recharging dock. I made a big carpet rover using one 6V and one 12V SLA cell. I’m convinced that the battery weight added traction and consistency, allowing it to achieve remarkable repeatability when dead reckoning through my house. See my video at https://www.youtube.com/watch ?v=PX0IhUqnwrk.

Figure 3. Swarm.

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Q

. I am interested in studying swarm behavior, so I’m looking to purchase a dozen or more small low cost robots. I’d like to keep the hardware investment below $500. What kind of robots should I buy? Ran Alford Seymour, IL

A

. THAT is the million dollar question. Unfortunately, the price for a dozen real “swarm” robots (Figure 3) may be closer to that million than the $500 total you mentioned. Your price is unrealistic at $41.67 per robot. In fact, I don’t know of a single $500 robot platform that comes ready for true swarm action, so I suspect your price is off by an order of magnitude or more. Futurists promise cheap swarm robots all day long, but have yet to deliver. My only “swarm” project was getting three Scribbler robots to play follow the leader. Check out my video at https://www.youtube.com /watch?v=seQXPRXzHtQ. Entire books and research theses have been written about the complex behaviors demonstrated by single robots with multiple concurrent goals. BEAM guru, Mark Tilden gives a great demo at https://www.youtube.

com/watch?v=7ncDPoa_n-8. Multiple robots interacting to achieve a common goal gets far more complicated very quickly. There are some university-based swarm platforms described at https://en.wikipedia.org/wiki/Swa rm_robotic_platforms. True swarm robots need lots of sensors, wireless communication with each other, and probably a host controller or network or IoT (Internet of Things) capability. They will need unique IDs and some location/position feedback; possibly from an overhead camera. I would suggest that you rethink your goal to clarify exactly what you are after. Real “swarm” behavior is very nebulous and difficult. Two or three robots collaborating is a much more reasonable goal to demonstrate. Your $500 might buy several Parallax S3s, or several Pololu 3Pi or Zumo robots which could communicate with each other, but you’ll still have to come up with some pretty fancy swarm code to get them working in concert. I would recommend taking a look at what the RoboCup guys are doing at www.robocup2016 .org/en. This is an ongoing challenge to make a team of soccer-playing robots. Moving a ball toward and into a goal is a simple and demonstrable feat, requiring cooperation and collaboration between robots. If you had four robots, you could play two against two to test different strategies. Then, apply those to all four bots working together as a “swarm” with a common goal. As with most robotic projects, it pays to start on a small scale and master the basics before unleashing your Dirty Dozen on the world.

Q

. I have an animatronic mad scientist head prop I built a while back using Futaba S3003 servos. It uses one servo to move the head left/right and another

Ostendorff - Mr Roboto - Jun 17_MrRoboto - Sep 15.qxd 5/2/2017 3:48 AM Page 15

to move the mouth. The left/right motion was always a strain for the small Futaba and it recently quit turning (I think the internal gears stripped). I would like to replace it with something a bit stronger. Do you have a rule of thumb for choosing servo strength? Bobby Hulsey Philadelphia, PA

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. This question comes up a lot. The S3003 is a great affordable servo with light-duty nylon gears. Your application clearly requires a bigger and/or stronger servo. If you have room for a quarter scale servo, even a $10 Vigor VS-11 would be a marked improvement over an S3003. It has nearly five times the torque of an S3003. The gears are still nylon but bigger, wider, and stronger. Heck, for just $10, order several now for future projects and thank me later. If you still want standard-sized servos, you can switch to either metal or Karbonite gears, which are several times stronger than nylon gears, and likely have more gear reduction and torque as well. Quality metal gear servos can get very expensive. It takes willpower to avoid the temptation of eBay’s $4 MG995/MG996 metal gear servos (#201606181242), but they are cheap for a reason. They are low grade knockoffs

with serious quality control issues and poor repeatability. Check out this “world’s worst servo” MG995 review at www.rcmodelreviews. com/mg995review.shtml. Some versions have bearings, some bushings. “You nevuh know whatcha gonna get.” The only way I use these is to gut them to make a strong compact DC gearmotor. Remove the electronics and pot; also yank the steel stop pin from the brass output gear. Works fine.

Q

. My friends and I want to build a bartending robot. We have found some good online resources for source code and between us, we have some time, money, and (some) skill. Our first run through used solenoid valves to dispense the liquids, but we found these to be too inaccurate. We were told that peristaltic pumps work better. We’d like to build some but don’t know where to start. Are there any plans from other robo-bar builders? Carl Wright via Email

A

. What a fabulous project! You’ll either be very popular with your neighbors debugging your system or kill your liver testing alone (Figure 4). I actually had my Heathkit HERO 2000 robot bartending at my Christmas party some 20 years ago. It was a labor of love. I have a dusty VHS tape of that somewhere; someday I’ll find it, digitize it, and put it on YouTube. The robot arm picked up various bottles from specified locations and poured into a central cup location. The booze was in baby bottles. I had cut back the rubber nipples while experimenting to get a Figure 4. Bartender. fairly consistent glug-glug flow rate whether full or

Figure 5. Magic tap.

nearly empty. More recently, I have used an automobile windshield washer pump to dispense margaritas. You can see that at https://www.youtube .com/watch?v=HTuYd1jhP5Y. To be honest, I’ve bought several battery-operated TV “MagicTap” dispensers (Figure 5) for future projects. They work very well, provide a constant flow rate, and are likely more food-grade and sanitary than a windshield washer or fuel pump! You’ll probably want to remove the push switch and have a microcontroller switch on the appropriate pump after the cup is moved under the nozzle by an arm or a turntable. Cheers!

That’s all for this month, gang. Please keep those cards and questions coming! Email me at roboto@servomagazine and let’s find some As to your Qs. SV

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NEW PRODUCTS Mini V-Wheels

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ini V-Wheels now available from ServoCity are a more compact alternative to standard V-Wheels. Like the V-Wheels, these too are constructed of high-density acetal plastic for low rolling resistance and excellent wear characteristics. The Minis, however, are turned down to a smaller size to create more compact linear motion assemblies with fewer parts. Whereas the Standard VWheels sometimes require an additional bracket to properly space them from the rail they run on, the Mini V-Wheels are able to mount on the Actobotics 1.5" pattern which can be found on nearly any Actobotics part. Use Mini V-Wheel standoffs if you're installing the wheels onto a part with through-holes (such as channel) or use Mini V-Wheel spacers if you're installing onto a part with threaded holes (such as a pattern mount). Mini VWheels are sold individually and come with a pair of pressed-in 5 mm ID ball bearings. Price is $6.99.

Mini V-Wheel Spacers

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ini V-Wheel spacers from ServoCity are intended to be used with the Actobotics Mini V-Wheels. The spacers have an OD of 5 mm so that the bearing of the Mini V-Wheel slides over; the length is the same as the overall width of the Mini V-Wheel. The spacer acts as a collar to keep pressure from being applied to the bearings within the Mini V-Wheels when a fastener is tightened down to hold the assembly together. These spacers can be used in conjunction with our 6-32 standoffs if you want to create an overall height other than what is available in the Mini V-Wheel standoffs. They can be paired with a single 0.250" OD spacer so that a long screw can pass through both spacers and into a threaded hole, or they can be used in-between multiple 0.250" OD spacers to create a Mini V-Wheel 'sandwich.' These spacers are sold in packs of four for $4.99.

Clamping Shaft Couplers

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lamping shaft couplers also available from ServoCity offer an excellent way to fasten one shaft to another, whether you’re connecting two shafts of the same diameter or you’re looking to connect a metric diameter shaft to an imperial diameter shaft. There are 54 different models available derived from bore diameters starting at 1/8” up to 3/8” in imperial and 3 mm up to 8 mm in metric. Dual 6-32 pinch bolts ensure a no-slip connection that won’t mar the shafting. The overall height of 0.6” and swing radius of 0.5” makes fitting these couplers into

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compact spaces simple. Price is $4.99. For further information, please contact:

ServoCity

www.servocity.com

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Upgrade for PICBASIC PRO

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he much anticipated upgrade to PBP 3.1 from M.E. Labs is now available for download. New device libraries support the latest PIC microcontrollers in PBP 3.1. This includes support for PIC18FxxK40, PIC16F183xx, PIC16F188xx PIC16F153xx, PIC16F177x, and PIC10F32x devices. Among the features offered in the new devices are

Peripheral-Pin-Select (PPS; allows you to specify peripheralpin locations) and 128K of code space in a 40-pin package. Long awaited in PBP, the 10F320/322 offers a tiny SOT6 package with midrange architecture and 64 bytes of RAM. For further information, please contact:

ME Labs

www.melabs.com

6-1/2 Digit Benchtop Multimeter

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aelig Company, Inc., introduces the Siglent SDM3065X: an economical 6-1/2 digit dual-display digital multimeter that is suited to high-precision, multifunction, and automation measurement applications. It combines basic high-accuracy measurement functions with multiple math and display choices, and special features including histogram, trend chart, bar chart, statistics, hold measurement, dBm, etc. The SDM3065X multimeter's front panel features a 4.3" (480 x 272) high resolution color TFT-LCD display that clearly shows the 2,200,000 count readings. This DMM's clear keyboard layout and operation make it easy and quick to use — especially with its built-in help system. The many interfaces for remote storage and communication include USB Device, USB Host, and LAN. The Ethernet connection interface supports the common SCPI command set. It is especially well suited for the needs of high-accuracy measurements. It even includes built-in cold terminal compensation for thermocouple temperature measurements. Reading at up to 300 samples/second, the SDM3065X DMM takes measurements of true-RMS AC voltage and AC current, resistance to 100M ohms, capacitance to 10,000 microfarads, continuity and diode tests, frequency and period measurements, and temperature, with support for thermocouple and RTD sensors. It contains 1 GB of Flash memory for storage of configuration and data files, and also supports USB external storage. Siglent's EasySDM software (provided free) allows for easy PC connectivity, external control, and display. Housed in an attractive compact (11.6" x 10.3" x 4.3") prop-stand case, the SDM3065X weighs only 7.5 lb. The Siglent SDM3065X's combination of comprehensive features, ease of use, and versatile

Saelig Company

www.saelig.com

Is your product innovative, less expensive, more functional, or just plain cool? If you have a new product that you would like us to run in our New Products section, please email a short description (300-500 words) and a photo of your product to: [email protected]

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)

For the finest in robots, parts, and services, go to www.servomagazine. com and click on Robo-Links.

functionality makes this multimeter a perfect generalpurpose/high-accuracy measuring tool. The SDM3065X is available now for $729. For further information, please contact:

   

  




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bots

IN BRIEF

LORD OF THE WIRE JUNGLE enerally, the term “aerial robot” is synonymous with “drone,” but there are lots of other ways for robots to avoid spending time on the ground. One of the most creative comes from Georgia Tech Professor, Jonathan Rogers who has been working on a sloth-inspired aerial robot named Tarzan. The machine is designed to swing around on overhead wires strung above fields to monitor growing crops. One day, it may swing around electrical wires in cities too. Tarzan is built with carbon fiber arms, reinforced with aluminum. Each arm has a DC motor at its base, and the shafts of those motors are coupled to each other. A bearing on the coupling shaft keeps the payload pod attached securely, while also allowing it to hang parallel to the ground irrespective of the orientation of the arms. The robot’s hands are 3D printed grippers with embedded IR sensors that can detect when a wire passes them and trigger the grippers to close tightly around it.

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LONG NECK ROBOT hmniLabs (a robotics startup based in Santa Clara, CA) recently launched a new consumer telepresence robot on Indiegogo called Ohmni. With a lightweight design,

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Tarzan is so new that it doesn’t have much of a payload yet, but eventually, the plan is to include a high resolution video camera as well as an IR camera for assessing plant health and hydration.

integrated screen, and easy-to-use software, Ohmni is designed to be the most accessible (and affordable) mobile telepresence robot yet. Ohmni is heavily focused on ease of use, which is always a good idea when developing a robot for consumers. It arrives completely assembled (folded in half), and setup consists of unfolding it. The display, audio, and video hardware are all integrated, so there’s nothing to mess with there either. The robot itself is 4’ 8" tall, and weighs just over 18 pounds. It runs Android 6.0 on an Intel X5 processor, with 64 GB of onboard storage and 4 GB of RAM. The lithium battery will keep the Ohmni moving and chatting for five hours, and the included dock will give you an hour of life for every hour of charging. Ohmni does include an autodocking feature with minimal autonomy: As long as the cameras can see the fiducial marker on the dock, the robot can orient and dock itself. One feature you’ll find on Ohmni that distinguishes it from other telepresence platforms is a tilting neck. Not pan and tilt, because it’s not designed to let you look around. Rather, it’s just a single extra degree of freedom that allows Ohmni to look up, down, and nod.

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bots

IN BRIEF TEA TIME IYer and computer scientist, Paul-Louis Ageneau built a biped robot reminiscent of the BOB and Otto robots, but he has decided to put his own unique spin on this particular design as he isn’t a fan of their square shape. Ageneau built his biped as a dancing robot teapot. Perhaps he built this in honor of Mrs. Potts — the ceramic teapot from Disney’s Beauty and the Beast — since it’s hard not to compare the two. Ageneau designed the 3D printed teapot himself to ensure it was uniquely his. To do so, he used the 3D modeling software OpenSCAD to design the various parts for the robot and then 3D printed them in polylactide. The robot includes four servos (two in its hips and two in its ankles) that are connected to an Arduino

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Pro Mini and powered by a 9V battery. The robot teapot can even play its own music while dancing, as long as you can connect a piezo speaker to your Arduino board. Check it out at https://chapelierfou.org/ 2017/04/plasteac-a-dancing-teapot/.

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To post comments on the articles included in this section and to find any associated files and/or downloads, go to www.servomagazine.com/index.php /magazine/issue/2017/06.

Robot Wars, Girls, and Glitter ● by James Baker uilding a fighting robot is difficult. Building a 220 lb fighting robot is very difficult. What would you do if you were given five weeks, zero budget, and a onetime opportunity to fulfill your dream by taking part in the BBC TV show, Robot Wars? Allowing your nine year old daughter to design and help build the robot would probably not be your first suggestion. Robot Wars had not filmed a new series during (my daughter) April’s

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Featured This Month: 20 Robot Wars, Girls, and Glitter by James Baker

22 EVENT REPORT: Motorama 2017 by Nate Franklin

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lifetime, so when the announcement was made that the cult UK show was to return, robot-crazy April was determined to be there. Already familiar with fighting robots — having attended her first event at three weeks old — she was a veteran maker, builder, and STEM presenter helping her dad with dozens of robots and engineering projects. One thing that became apparent during those years, was that April had an ambitious creativity that both challenged and thrilled those who worked with her. April had entered a design for the new Robot Wars show that took inspiration from the F-117 Nighthawk stealth fighter, and the chainswords found in the Warhammer 40,000 games to create the GlitterBomb robot concept. The armoured shell was to be a facetted triangular structure in homage to the stealth aircraft, and the toothed axe had holes cut into it to hold the multi-colored glitter that would burst out when hitting other robots. A pink ballet tutu added a final girly twist. GlitterBomb was built using the

tools, skills, and experience available at the time, with April mocking up the shape on a frame built for her, as she cannot yet weld. Using artist’s foamcore board, April created the outer shell and designed several axe shapes. Once the foam-core robot was finished, it was labelled and taken apart so that each part could be

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drawn in 2D CAD. The CAD was sent to a local sponsor — KMS Hardrange, in Flint, North Wales — for laser cutting in 3 mm AR400 wear plate and 4 mm titanium. While April left the rest of the fabrication of the robot to her dad, she started work on the image and theme of the robot and team. The robot was always going to be pink (according to April), but it needed an identity that would carry through the team apparel, social media presence, and on the robot itself. With no budget, creating a striking and memorable marketing identity was important in finding sponsors and supporters. April and her mum incorporated the GlitterBomb logo and color scheme into the pitch made to potential sponsors, and it was not long before several local companies expressed an interest in helping a nine year old girl build her fighting robot. In fact, having April lead the team at meetings with local companies helped to secure far more support that expected, and thankfully the entire robot build was underwritten by local sponsors. As the filming date approached, the parts needed for the robot were donated or

purchased by April’s sponsors — just in time to be fitted to the emerging robot. Unfortunately, the lovely pink tutu designed by April and made by her mother (a professional costume maker) would have to be cancelled due to entanglement rules, and the glitter inside the axe was outlawed after discussions with the Robot Wars technical team. In retrospect, the robot was better for these changes, but it was a disappointment for a little while as April’s outfit had a matching tutu which she retained on the show, and the name GlitterBomb made less

sense without actually being able to glitter-bomb the opponent. Fortunately, she is thankful now for the way things went. Two days before leaving for filming, GlitterBomb sat ready for paint, and a battle of wills began. April wanted the robot to be entirely covered in bright pink paint and sprayed with glitter lacquer. Her mum wanted something to replace the lost tutu, as it smoothed the change in the shape of the armor, and daddy wanted a cool black and chrome color scheme, with flames and other 1980’s clichés. After much discussion, April went away to draw a picture. When she came back, she had drawn GlitterBomb as a bright pink robot with glitter lacquer, silver flake metallic black top and back plates, and a bright silver stripe where the sloped lower armor blended into the upper sections. The next two days were spent painting and applying stickers as a family, before loading up and leaving for the show. Having a youthful captain, designer, builder, logistics, and sponsorship manager may sound like a crazy idea, but this is a crazy sport and GlitterBomb ended up as a robot that stood SERVO 06.2017

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out. Our time on the show was not as successful as we would have hoped — going out due to a silly technical failure in the first round — but the experience was amazing. April would have enjoyed being on Robot Wars however it happened, but to have April lead the adventure made everything so much more rewarding, challenging, exciting, and in many ways easier. As reviews and recommendations go, I guess suggesting you defer your fighting robot design to a nine year old girl might not be all that sensible, but if you allow yourselves to do something a little crazy with your next robot, you might be surprised by how great it turns out. Good luck. SV

EVENT REPORT: Motorama 2017 he Northeast Robotics Club (NERC) once again held its robot conflict event at Motorama. The event took place in February, in some surprisingly nice Harrisburg weather. Thanks to the resurgence of BattleBots™ on television, nearly all of the weight classes were filled with contenders. In order to accommodate the overabundance of bots, a second arena was brought to the event. This arena (built by Kyle Singer) was run by Chuck Butler from Team Pneusance for the Beetleweights on Saturday and Sunday. By having a separate arena for this weight class, the event was finished earlier than previous years. The Antweight and Fairyweight robots fought in an 8x8 arena. The

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Fairyweight division included bots like four-time champion Demise; 3D printed Speed Wedge UK; and lifters Scoop and Bug Bite. Two hacked BattleBots RC Tombstone toys also joined, but were unable to keep up with the other robots. Demise ran through the bracket undefeated, taking out bot after bot

Dinner Time

● by Nate Franklin with ease. Bug Bite — built from an Altoids mint container — managed to reach the finals after outdriving Scoop. In the final, Demise continued its undefeated streak by surgically removing both of Bug Bite’s wheels. In the Antweight division, many old favorites and new robots came to test their might. Deadly undercutters Vile Ant and Low Blow returned, along with drum spinners like Physique Black and Poco Tambor. Some new bots included Foiled!: a 3D printed undercutter with an airfoil built into the disc. This allowed the bot to stick to the ground after big hits, and also “hover” around the arena. A whole fleet of robots came all the way from California to show the East coast bots how it’s done. The challengers

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Hercules

Wedding Gift Pitter Patter

came from Team Bad Kitty and Fast Electric Robots, who had previously been seen on ABC’s BattleBots. However, they fell short of glory after facing some deadly foes. After reaching the final, Foiled! was no match for the driving skill of Michael Connerton, with his clamper/ lifer hybrid Hercules getting the win. There were over 60 Beetlewight robots competing at this year’s Motorama. They ranged from veterans like Revenge of Dr. Super Brain and Silent Spring, to new bots from MIT and Georgia Tech. Right at the beginning of round one, the bots to fear stood out. Eggbeater InsaniTI made a great first impression, along with drum spinner Radii. One of the most impressive

robots in the field was Dinner Time. From the same builder as last year’s champion, Margin of Safety, Dinner Time featured a similar low profile but featured three interchangeable weapon pods: two different horizontal spinners and a drum. Meanwhile, the always vicious Silent Spring worked its way up the loser’s bracket, taking out bot after bot on its way to the final. In the winner’s bracket final, Silent Spring

Bug Bite

Demise

dispatched of Radii by brutally removing its drum. Dinner Time performed the same action to Radii in order to meet Silent Spring. After two final fights, Dinner Time got the win. The Hobbyweight bots were savage as always. Vertical spinners like Not Disko and Minor Threat 3 had no trouble tossing their opponents to the ceiling. Meanwhile, wedges and lifters like Shake, Nothing Special, and Isotelus Rex did their best to outdrive the heavy hitters. Drum spinner Drumadillo came all the way from California to fight, only to get splattered across the arena by Boom Zone, who ended up SERVO 06.2017

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Big Ripto (right) and its victim Duck Yeah (left). Huge

smoking after the hit. Drumadillo managed to get put back together to fight again, but suffered the same fate at the hands of Steel ‘n Shock’s terrifying eggbeater. One of the more memorable moments in the Hobbyweight division was the multibot Army Ants, which was made up of four Beetleweight bots. Needless to say, the bots saw lots of airtime. As Not Disko made an undefeated run to the final, Minor Threat 3 and Predator made their way through the loser’s bracket. With such power behind its weapon, Minor Threat 3 broke Steel ‘n Shock’s eggbeater on its way to the finals. Later, it gave Predator a humiliating smackdown, breaking its eggbeater before making it faceplant on its own broken weapon assembly. Reigning champion Not Disko refused to give up its crown, and delivered a devastating punishment to keep its title for the second year in a row. As always, the Sportsman class featured a variety of designs. From Fairyweight Antweight Beetleweight Hobbyweight Sportsman Featherweight

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1st Demise Hercules Dinner Time Not Disko Pitter Patter megatRON

hammers like Iron Golem to the meccanum wheeled lifter of Translationally Inconsistent, the class showed off some impressive bots. Also returning to the competition was Jon Durand, who had previously taken a hiatus from competing to help out emcee-ing NERC events. He brought a robot called Wedding Gift — made from a robot that was the ring-bearer at his wedding. Right off the bat, shuffler Pitter Patter made a name for itself by dominating its way through the brackets. With a saw on an arm, it made some nice sparks while slicing into its foes. Veteran lifter Gigarange made a great run through the brackets, defeating its foes with impressive driving. However, it met fellow lifter BEEESS??, who advanced to the finals. In the end, Pitter Patter claimed the title on a judge’s decision after doing enough damage to disable its opponent’s lifter. When it came time for the Featherweights to fight, all eyes were on Big Ripto. In its opening fight, Big Ripto hurled Duck Yeah into the

2nd Bug Bite Foiled! Silent Spring Minor Threat 3 BEEESS?? Huge

3rd Scoop Discharge Radii Predator Gigarange Speed Wedge 30

ceiling like nobody’s business. When it came time to face former champion Triggo, Big Ripto punted it across the arena. Ray Billings — fresh off his win at Battlebots — brought a new bot: a vertical spinner named Soylent Green. However, the real star of the Featherweight class was Huge. This bot lived up to its name. It was a bigwheeled vertical spinner that won everyone’s hearts and fought its way into the finals. megatRON — one of Huge’s early victims — worked its way through the loser’s bracket. It managed to take out Soylent Green despite taking lots of abuse by cutting its opponent’s motor connections, and outlasting Triggo after years of being another one of its victims. Big Ripto ended up in the loser’s bracket after a shocking loss. Despite sending Speed Wedge 30 to the ceiling multiple times and breaking its steel wedge, Big Ripto ended up upside down and counted out. Later, Big Ripto had no problem shredding megatRON’s wedge, but a broken electrical connection left Big Ripto dead in the water. megatRON managed to balance Speed Wedge 30 on its back to meet Huge in the finals. After battering and bashing the giant wheeled bot, megatRON got the win. Once again, Motorama was a successful event. A special thank you to the folks who run the event, and all the builders who came to put on a great show. SV

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By Holden Berry

DIRTY JOBS FOR ROBOTS IN THE TANK As human kind works The Scantron robot — created to deeper and deeper into our clean out sludge and sediment. technological age, we are amazed every day by new robots and software that make our lives easier, more convenient, or more fun. We are awed by Facebook videos of gleaming shiny new technologies that will be “the next big thing.” With all these glittering technologies, it’s easy to become lost in the glitz and overshadow the actual technological advances that will make the world a better and safer place ... until now. ome robots don’t get the iPhone treatment or a red carpet rollout, but that doesn’t mean they’re any less important. These are the robots doing dirty jobs that are making workplaces cleaner and safer, and they deserve to be honored too! Scantron Robotics is a company that doesn’t need to fit its robot with a shiny chrome exterior. It would be pointless. That chrome would be dirty and dull by the time it finished its first job. As it’s pulled out of an industrial tank, the finished product is what’s left shining. They’ve designed a robot that dives into industrial water tanks (often used in manufacturing plants), and cleans out all the sludge and sediment that’s settled on the bottom. Although this may seem like a simple and straightforward job, complications await at every corner. “A method that works perfectly for one job may not be as effective on another,” Randi Morgan, the creative director for Scantron Robotics explained. “The remediation methods we choose are highly dependent on the contents inside each tank.” This means that every approach must be evaluated and tailored.

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The traditional cleaning method for these tanks can be dangerous, and can have hidden long-term costs that Morgan says are eliminated with their robot. “Industrial tanks are cleaned in a couple of different ways, each of which requires a ‘turnaround’ or ‘outage.’” Because

The Scantron robot cuts through sediment in industrial tanks.

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To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index.php/magazine/issue/2017/06.

into the tank using a custom crane, then sinks to the bottom where the sediment and sludge has settled. As it crawls along the bottom of the tank, it cuts through the sludge, pumping it into a separate tank where remediation services “dewater” it, and return chemically treated water back into the tank. “Our methods ultimately provide a larger overall cost savings for the client,” Morgan commented. Although the cost upfront for robotic cleaning is greater, the traditional methods have hidden costs. “Our services can be done while the facility remains in full operation.” In addition to that, there’s no need to A clean trail is left as Scantron’s robot crawls along the tank. drain the tanks either, which saves on the disposal costs and the costs associated to refill the tank with chemically treated water. Morgan says companies can’t afford to shut down operations willy-nilly, not using any people in the cleaning process also saves in they often put off the cleaning. permit expenses. “The confined space entry requires special The tanks must be drained completely. Typically, a vacpermits, as well as the presence of dedicated emergency truck company is required to send a team into a (oftentimes response personnel.” dangerous) confined space entry. “Many lives have been Although at the moment Scantron’s business is limited, taken in confined space tank cleaning accidents,” Morgan they are working constantly to expand it. “We’re contracted says. Just earlier this year, three lives were lost from with facilities in the steel and chemical industries; however, poisonous gas in a confined space entry. In 2011, a study our services can be useful in almost every industrial confirmed that nearly two lives were lost a week in market.” confined space entry. Morgan cited “food processing, automobile After the tank has been cleaned, it’s refilled with the manufacturing, paper and pulp mills, nuclear power plants, chemically treated water. An alternative method uses oil refineries, and retail distribution,” all as potential areas professional divers. This method avoids the need to drain of expansion, and their marketing team is working on the tank, but all pumps and machinery must still be turned getting more industry leaders on board. “We’re expanding off, and human lives are still put in direct danger. our presence at trade shows and developing our sales and Scantron Robotics’ method takes human lives marketing strategies.” completely out of the equation. The robot is first lowered He knows that once he gets a client interested that they’ll be satisfied. “Our clients are left amazed that our services were so effective. Most of our ‘trials’ turn into long-term contracts and lead to many more jobs within the same facility.” Scantron admits that their robot and their process aren’t perfect yet though, and that they have a long way to go. “We would love to develop a robot and system that can clean tanks that contain explosive materials, such as an oil tank.” Morgan brings up the issue of safety again here, knowing that these explosive materials are often the most hazardous. “We’d also like to improve upon our water remediation process,” Morgan mentioned. They currently use a mixture of methods depending on what materials they are working with. A method for one material could be useless for another material. “We are always welcoming new ideas and partnering with companies who can increase our efficiency Groundhog, preparing to enter a mine.

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Berry - Scantron tank cleaning bot - Jun 17_Blank Rough SV.qxd 5/2/2017 3:54 AM Page 27

Groundhog is a fully autonomous mine mapping robot.

in our water remediation process,” Morgan commented. He expressed an eagerness to improve on Scantron, and encourages collaboration every step of the way. Although cleaning out industrial tanks is one robotic dirty job, there are other robots that don’t get the glory they deserve as well. In cities across the US, anywhere from tens of thousands to hundreds of thousands of abandoned mines are spread underground. These mines were not mapped out or recorded until 1976, meaning no one is exactly sure of the location and amount of mines. For years, teams were sent underground to map out and record these mines, where cave-ins and gas pockets could threaten them at every corner. Bring in Groundhog: the robotic solution created by researchers and engineers from Carnegie Mellon, Stanford, and Freiburg University. Groundhog is an autonomous robot that scans its surroundings and creates a 3D model of the mine. Groundhog recently successfully navigated and mapped a main corridor in an abandoned mine near Courtney, PA. With autonomous technologies drastically improving, it’s a fair bet that the effectiveness of Groundhog will only get better. The Scantron robot and Groundhog are just two innovations that fill a need in society by utilizing technology. Dangerous and hazardous work conditions were eliminated and lives were saved. They’re not glamorous, shiny, or fun. They do dirty jobs that go unrewarded and under-praised, but “someone’s” got to do them. These robots are replacing the need for humans to risk their lives — a perfect use of technology to improve society. The more they grow and develop, the safer the industries will become. Randi Morgan knows this. He knows that their robot isn’t going to attract the attention of trendy Facebook videos fitted with glitzy titles, promising “the next big

The Carnegie Mellon Robotics Institute posing with Groundhog.

thing.” However, he also knows their robot is going to save lives. “Our company mission is to someday lead the industry and eliminate the need for people to risk their lives in this field.” SV

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Hacking an RC Car with the Mentor’s Friend A couple of years ago, I designed a kit for Nuts & Volts (SERVO’s sister publication) that implemented a version of Jeff Ledger’s open source Pocket Mini Computer. It’s a Propeller based retro computer that emulates those early 1980’s classic computers you hooked to a TV and programmed in BASIC. The kit was aimed at parents and grandparents who wanted to share a technology experience with youngsters, but were a bit uncomfortable with learning the Arduino, Raspberry Pi, or other current platform. We called the kit the “Mentor’s Friend” and nicknamed it the “Amigo.” This article introduces the Amigo to SERVO readers and presents a simple computer-controlled hardware project (hacking a toy RC car) that you and a budding roboticist can build and explore together.

Figure 1. The Build-It-Yourself Mentor’s Friend. Just add a VGA monitor, PS/2 keyboard, and a small DC supply for loads of “old style” computer fun!

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Figure 1 shows the completed Mentor’s Friend which uses the amazing Parallax Propeller P1 chip to provide all the I/O for the little retro computer, plus a tinyBASIC interpreter with 4K of program memory. The Amigo Color BASIC interpreter is indeed tiny — integer arithmetic only; no support for strings; no arrays; no explicit DATA statement. However, it contains everything you need to introduce programming fundamentals to youngsters, without the instructional distractions of separate IDEs (integrated development environments), compilers, and other complexities. One advantage of BASIC is that many would-be mentors can still find their way around in that “days of yore” language, regardless of their current microcontroller fluency, and Nuts & Volts has offered a series of articles on Color BASIC to help mentors easily explore programming fundamentals with their young protégés. In addition to a simple introductory programming platform, the Amigo provides direct program control over 16 Propeller I/O pins, with a small breadboard and some

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By Dane Weston

To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index.php/magazine/issue/2017/06.

Figure 4. The TLP222AF solid-state relay offers a simple way to convert a Propeller I/O pin signal to an isolated switch closure — perfect for interfacing with the RC controller.

LEDs and switches onboard to make that useful. These features make it easy to explore simple computer-controlled hardware projects directly from BASIC in one self-contained build-it-yourself package. In this article, we’ll build a daughterboard “shield” for the Amigo, and use those hardware-control features to drive a toy RC car from the Amigo keyboard. Last year before the holidays, I noticed various radio controlled toys on sale at my local drug store. My first thought was — of course — I wonder if I could interface these to the Amigo? At the bargain basement price of less than ten bucks each, I couldn’t resist. So, I picked up a couple of RC toy cars and added “remote control car” to my list of potential Amigo projects. When I started the “toy car” project, the first thing I checked was the controller. As I suspected, the forward/reverse/left/right controls were simple switches actuated by the controller joysticks (see Figure 3). I began examining ways to close those switches under Propeller I/O pin control. I had some small mechanical relays on hand, but most couldn’t be driven directly by an I/O pin. I also had a bunch of different transistors available (my collection actually dates back to the 1960s, thanks to some I inherited from my dad), so a simple transistor switch arrangement seemed promising, and that’s where I began my search for an interface solution. Finding an effective transistor switch to shunt the controller mechanical switches proved more difficult than I expected. Without going into needless detail, the transistor bias arrangements that worked often had unintended effects, like turning on the controller power indicator when the power switch was off. (I know, a real head scratcher, and one that I couldn’t figure out.) To further complicate things, controllers from different manufacturers were completely different, so transistor bias arrangements were not transferable one to another. Clearly, I needed a different approach. Enter the TLP222AF solid-state relay. When my

Figure 2. Typical toy RC car and controller. The Forward/Reverse and Left/Right controls operate pairs of SPST switches which are easy to interface to the Amigo.

Figure 3. Inside the RC car controller. The plastic control sticks have been removed to show the SPST switches for Forward/Reverse and Left/Right.

transistor-based approach fizzled out, a quick Internet search pointed to a more modern alternative: the optically coupled MOSFET solid-state relay. A browse through the many options available led me to the TLP222AF: a four-pin DIP IC which uses an internal LED to switch loads up to 500 ma. As shown in Figure 4, the TLP222AF interfaces cleanly with a Prop I/O pin with nothing more than a currentlimiting resistor — no muss, no fuss, and no transistor bias calculations or leakage current. To implement a four-relay controller interface, you have a choice: either build the circuit directly on the Amigo breadboard; or construct a little “shield” board that plugs SERVO 06.2017

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Figure 5. The Amigo/RC car controller interface using the TLP222AF. Validate the interface to your controller with just one relay before you lay in the other three.

into the breadboard headers. If you’re just going to do a temporary “proof of concept,” the breadboard approach will work just fine. However, if you want to show off your car-driving Amigo in the future or use this approach for your own computer-controlled hardware project, building a shield board is the way to go. Figure 5 shows how I implemented the circuit in Figure 4 on the Amigo breadboard, with one relay for each of the four switches in the toy car controller. Make sure you

align the relays properly. Pin 1 (indicated by the little dot) goes to the 330 ohm resistor and on to ground. You may want to build things one section at a time and test it with your controller before you build out all four sections on the breadboard. Also, the I/O pin assignments are flexible; those shown in Figure 5 will match the software assignments in the article. To build a shield board, you’ll need a Parallax EDU circuit overlay board (P/N 32999), four TLP222AFs, four 330 ohm resistors, an eight-pin female SIP header (optional), and some hookup wire. The circuit overlay board kit from Parallax includes the male headers that go on the underside of the board to connect with the Amigo breadboard headers. Component layout is not critical; just be sure to get them on the “component” side — the opposite side from the male headers. Also, any resistor in the neighborhood of 330 ohms should work. I used 470 ohms with no problems. If you are using Figure 5 as a guide for the component layout on your shield board, note carefully that the labeling on the TLP222AF chips is shown upside-down for readability in the figure. Make sure to align the relays with the “dot” connected to the Prop I/O pin. You may want to double-check your layout against Figure 6 before you solder everything down. Once everything is complete, plug your shield into the Amigo breadboard headers (this may take a little jockeying the first few times) and validate the functionality of each relay with a multimeter and the following code: 10 20 30 40 50

REM *** RELAY.BAS *** INPUT “Propeller I/O Pin? “; p PRINT “Toggling Pin “; p PRINT “Press Any Key to Quit.” OUTA[p]=1 60 PAUSE 250 70 OUTA[p]=0 80 PAUSE 250 90 IF INKEY=0 THEN GOTO 50 100 OUTA[p]=0

Figure 6. My build of a four-relay “shield” board for the Amigo, installed in the breadboard headers. It uses TLP222AF solid-state relays on the Parallax EDU circuit overlay board. Component layout is not critical.

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Once your four-relay circuit (either breadboard or shield) is good to go, it’s time to connect it to the RC car controller. Again, you have a choice in your implementation; this time, choosing to wire directly from the controller switches to the relay circuit, or installing a connector in the controller and building a separate shield/controller interface cable. Since I wanted to control the car without the Amigo as well as with it, I chose to install an eight-pin female header in the plastic controller shell and wired from it to the controller switches. I then built a short interface cable from some ribbon cable and two eight-pin male SIP headers: one end for the controller; and the other for my shield

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board or the breadboard. Again, wiring directly to the controller board makes good sense if you never plan to use the joysticks. Figure 7 shows my hack of the controller before I epoxied the SIP header into one side of the controller shell. If you look closely, you’ll see only five wires from my makeshift connector: one for each switch and one for the common. I connected one side of each relay pair together at the header and wired those to the controller switch common. You’ll also see the antenna disconnected, which I had to do to access the trace side of the circuit board. If you do have to remove your antenna, I suggest removing the controller battery (or batteries) first, and keep them Figure 7. Hacking the controller. I made an interface cable connector from a female SIP header, but you could just straight-wire directly from the controller removed while the antenna is not switches to the Amigo. connected just to make sure the final stage of the transmitter is protected instead of moving smoothly while I held down the “8” key. from an inadvertent reflected power zap. Initial investigation showed that the INKEY command was Figure 8 shows my completed hardware setup, with returning some zeroes even when the 8 key was held the relay shield installed on my Amigo and connected to down, which surprised me. Further investigation pointed to the controller via the ribbon cable. The first thing I did at some timing issues between my Color BASIC code, the Spin this point was run RELAY.BAS to validate the functionality of all four channels with the controller and RC car. For some reason, my system did not work on the first try, even though all interim tests had been successful. After I removed and reinstalled the car and controller batteries and spun the motors a couple of times, everything mysteriously began working as it should. With my Amigo now happily interfaced to the RC car, it was time for some software. The first software design choice was whether to use the keyboard or the Wii™ classic controller for user input to control the car. I liked the feel of the Wii controller, but since some readers may not have that device, I decided to go with the keyboard and use the numeric keypad to “drive” the toy car around. The scheme that I planned was to use the number “5” as the center “home” position, and the keys around the 5 key as directions relative to that center point. Thus, the 8 key would represent forward; the 2 key would be reverse; the 9 key would be forward right; the 1 key would be reverse left; and so forth. These INKEY values would turn on the appropriate relays, and an INKEY value of zero (no key pressed) would turn all relays off. Figure 8. My completed setup, with the relay shield board in place When I wrote a code snippet to validate this and interfaced to the controller via a spiffy ribbon cable. It works! keyboard approach, my RC car stuttered forward, Now for the software ... SERVO 06.2017

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keyboard interface code, and my keyboard. I found that I could manage this by inserting a PAUSE command in my BASIC code, but this made the car drive sluggishly. The bottom line of all this was that I couldn’t use a zero value from INKEY (no key pressed) to stop the car (all relays off). So, I decided to use the 5 key instead, and accepted the approach of having to press a key to stop the car; 5 would turn all relays off. This approach worked, and I quickly got used to pressing the 5 key to stop the zippy little car. In addition, I added a “all-stop” key just in case my old fingers (and old brain) got confused. I confess to using it more than once when “Zippy” was screaming headlong into the credenza. I also added some code that executes preprogrammed driving instructions. (What good is computer control if you don’t actually do something with it?) Here’s how my “car driving” code turned out, followed by a brief explanation of the key sections. There’s nothing illustrational in this code, and probably not much value to actually keyboarding it in. I suggest you download RACER.BAS from the article link and copy it to your SD card. Then, you can tweak it as needed for your situation: 5 REM ***** AMIGO RACER ***** 10 REM —- Initialize Things —15 F=12: B=13 REM <— Forward and Reverse I/O Pins 20 L=14: R=15 REM <— Left and Right I/O Pins 25 p=100 REM <— Pause in Milliseconds 30 j=0 <— Previous Keystroke 50 REM —- Print Main Screen —52 COLOR 63,22 54 CLS 56 LOCATE 15,1: PRINT “>>> AMIGO RACER! <<<” 58 LOCATE 4,3: PRINT “ > Use Keys 1-9 to Manually Control Car” 60 LOCATE 4,5: PRINT “ Or Function Keys For Stored Programs.” 62 LOCATE 3,7: PRINT “~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~” 64 LOCATE 3,9: PRINT “7=FORWARD/LEFT 8=FORWARD 9=FORWARD/RIGHT” 66 LOCATE 3,11: PRINT “4=STOP/LEFT 5=STOP 6=STOP/RIGHT” 68 LOCATE 3,13: PRINT “1=REVERSE/LEFT 2=REVERSE 3=REVERSE/RIGHT” 70 LOCATE 13,15: PRINT “ = ALL STOP!” 72 LOCATE 3,17: PRINT “~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~” 74 LOCATE 4,19: PRINT “F1=Hello F2=Circle F3=Waggle” 76 LOCATE 4,21: PRINT “F4=Your F5=Code F6=QUIT” 78 LOCATE 3,23: PRINT “~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~” 100 REM —- Main Loop —105 k=INKEY 110 IF k=0 THEN GOTO 105 115 IF k=j THEN GOTO 105 120 IF k=32 THEN GOSUB 1000 125 IF k>207 AND k<214 THEN GOSUB (k-204)*1000 130 IF k<”1” OR k>”9” THEN GOTO 105 135 GOSUB 2000 140 GOTO 105 995 REM —- SUBROUTINES —1000 REM —- All Stop —-

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Author’s book on Color BASIC for the Pocket Mini Computer

www.lulu.com/shop/display-product.ep?pID=4536358 1005 OUTA [F]=0: OUTA [B]=0: OUTA [R]=0 1095 RETURN 2000 REM —- Set Relays —2005 GOTO k+1961 2010 OUTA [F]=0: OUTA [B]=1: OUTA [L]=1: GOTO 2020 2011 OUTA [F]=0: OUTA [B]=1: OUTA [R]=0: GOTO 2020 2012 OUTA [F]=0: OUTA [B]=1: OUTA [R]=1: GOTO 2020 2013 OUTA [F]=0: OUTA [B]=0: OUTA [L]=1: GOTO 2020 2014 OUTA [F]=0: OUTA [B]=0: OUTA [R]=0: GOTO 2020 2015 OUTA [F]=0: OUTA [B]=0: OUTA [R]=1: GOTO 2020 2016 OUTA [B]=0: OUTA [F]=1: OUTA [L]=1: GOTO 2020 2017 OUTA [B]=0: OUTA [F]=1: OUTA [R]=0: GOTO 2020 2018 OUTA [B]=0: OUTA [F]=1: OUTA [R]=1: GOTO 2020 2020 j=k 2095 RETURN 3000 REM —- Run Program Step —3005 GOSUB 2000 3010 FOR n=0 TO t 3015 PAUSE p 3020 NEXT n 3095 RETURN 4000 REM —- F1 Program —4005 k=”8”: t=10: GOSUB 3000 4010 k=”5”: t=1: GOSUB 3000 4095 RETURN 5000 REM —- F2 Program —5005 k=”7”: t=5: GOSUB 3000 5010 k=”9”: t=20: GOSUB 3000 5015 k=”5”: t=”1”: GOSUB 3000 5095 RETURN 6000 REM —- F3 Program —6005 k=”7”: t=5: GOSUB 3000 6010 k=”9”: t=5: GOSUB 3000 6015 k=”7”: t=5: GOSUB 3000 6020 k=”9”: t=5: GOSUB 3000 6025 k=”5”: t=1: GOSUB 3000 6095 RETURN 7000 REM —- F4 Program —7005 REM <— Your Code Here 7095 RETURN 8000 REM —- F5 Program —8005 REM <— Your Code Here 8095 RETURN 9000 REM —- F6=Quit —9005 PRINT “bye!” 9010 END 9095 RETURN

[L]=0: OUTA

[R]=0: OUTA [L]=0: OUTA [L]=0: OUTA [R]=0: OUTA [L]=0: OUTA [L]=0: OUTA [R]=0: OUTA [L]=0: OUTA [L]=0: OUTA

Lines 5-78 of the program initialize a few variables up front (so you can conveniently change them if needed) and display the program main screen (see Figure 9). Lines 100140 are the program main loop, which gets a keystroke and then takes action based on the key value: • A key value of zero means no key pressed; get another keystroke. • A value equal to the previous keystroke means no

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A kit is available from the Nuts & Volts webstore that contains all the components to build the Amigo, including the pre-programmed EEPROM containing the Color BASIC “operating system” and a 2 GB SD card with the editor and some starter programs. Kit assembly is straightforward, with mostly through-hole construction, and the fact that you’re reading this magazine means that you probably have the tools and skills needed to make short work of the Amigo build. Or, if you already have a Propeller board with PS/2, VGA, and SD card interfaces, you can “roll your own” Amigo by downloading the Color BASIC source, adjusting the I/O pin assignments to fit your board, and then compiling/uploading the resulting binary to the EEPROM on your board. You can find the Amigo source code, schematics, and a description of Color BASIC at www.nutsvolts.com/uploads/ magazine_downloads/201512-Weston.zip. Or, if you are truly ambitious, download the Amigo schematic from the Nuts & Volts website and build out the circuits using your favorite construction techniques. Then, download the Color BASIC source or binary and Flash it to your EEPROM. Regardless of the method you choose, please use the N&V blogs to share your challenges and triumphs, or to ask for advice if needed. Good luck!

change; get another keystroke. • A value of 32 (the key) means “Emergency Stop;” turn all relays off. • Values between 208 and 213 (inclusive) are function keys F1 to F6 and execute stored programs, including F6 Quit Program. • Values between 49 and 57 are number keys “1” through “9” and set the appropriate relays. • All other values are not assigned; get another keystroke. The rest of the program contains the subroutines that execute the actions required by each “valid” keystroke. Lines 1000-1095 are the “emergency stop” subroutine, which uses the OUTA [x]=0 command to open all relays. Lines 2000-2095 set the appropriate relays for each numeric keystroke using a CASE statement built from Color BASIC GOTOs. This may seem like a lot of code, but it runs faster than a nest of IF statements. Note that the order of the OUTA statements in this section avoids having “opposite” relays (Forward/Back or Left/Right) turned on at the same time. Lines 3000-3095 run a single step of a coded “driving instruction” program by using the numeric value in variable

Figure 9. The Amigo racer software main (and only) screen. The program allows driving the RC car from the numeric keypad or from stored programs.

k to set the appropriate relays, then running t times through a timing loop that includes the pause variable p. You should adjust the value of the pause variable p to suit your car and driving conditions. My car runs much faster on tile than carpet. Lines 4000-4095 represent one set of driving instructions; in this case, to drive straight ahead (k = “8”) for about one second (t x p = 10 x 100 milliseconds). Note Line 4010, which sends an “all relays off” command that should be used at the end of each set of driving instructions. The remainder of the program includes a couple of other simple driving programs, room for your own, and an explicit “Quit Program” option. Even if you’ve had only limited exposure to BASIC, RACER.BAS should be fairly understandable to you. It’s simple, straightforward, and no frills. I think the Amigo is a great platform to introduce youngsters to programming fundamentals and simple hardware interfaces — all in one self-contained package that they can truly master. With that mastery, comes confidence and the curiosity to try something else. Who knows where that might lead? This completes our introduction to the Mentor’s Friend, and how you can use it to drive a toy RC car using a simple hack of the controller. The relay shield described in this article could also be used to hack many other switch-based controllers, so let your imagination run wild! It gives your Amigo the ability to control loads of up to 500 ma with minimal muss and fuss, and there’s room on the shield board for some expansion. I hope you and a young protégé will give the Mentor’s Friend a try, and that it brings you many smiles! Have fun! SV

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DIY Animatronics Putting On a Face

By Steve Koci

What good is a fully functioning mechanical character without a face? For me, the most important and difficult exposed surfaces dilemma is how to complete the head. This is where my good friend, Robert Risley comes in. His mad skills as a sculptor make him an irreplaceable member of the build team!

R

obert has had a lifelong interest in Halloween since childhood. His passion has led him to work in numerous haunted houses, as well as being contracted to do a variety of freelance sculpting projects. His preference, however, is to work with home haunters, and we are extremely lucky to have him choose to work with us! During a brainstorming session, Robert and I were discussing ways to give life to our characters. Masks worked for some applications but were not really what we wanted for others. We strive to develop original characters whenever possible, so we wanted to create something that is not available to anyone else. That is when the idea was hatched to take an existing product that we are already familiar with and add to it. We would then be able to create original characters that fit within our themes. This is not the traditional method of sculpting with clay, making a mold, and then creating a finished product. We find it a much easier method that allows us to also incorporate our mechanisms, allowing for multiple movements. This process has worked so well for us that Robert is constantly being approached by others for advice and direction. Hopefully, this article will provide the necessary guidance for you to create your own characters!

Figure 1. A Lindberg skull — before and after.

Under Skull This process starts with a Lindberg skull which is normally used as a Halloween decoration. It provides an anatomically correct starting point, avoiding much of the difficulty in getting your sculpture started properly (Figure 1). Another advantage to starting with this skull is that the three-axis mechanism from Monster Guts (that I prefer) is designed to fit in it (see Resources). It allows us to incorporate the Teensy electronic eyes as well; I now

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Figure 2. Enlarging the eye sockets.

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DIY Animatronics To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index.php/magazine/issue/2017/06.

incorporate these into most of my characters (see Resources). I went into more detail on this mechanism and the eyes in the August 2015 and April 2016 editions of SERVO Magazine, respectively. Check out those articles if you would like to give them a try yourself. You will not be disappointed! Other preparations for the skull include enlarging the eye sockets to Figure 3. Interior grinding to prepare for eye screens. Figure 4. Adding the initial features accept the electronic with foil. screens which provide the eye animations (Figure 2). This also requires some significant modifications to the Once the structural modifications inside of the skull as we must have been made to the skull, there is grind out a substantial amount still some preparation to be done of material to allow the screens prior to adding the clay. Aluminum foil is glued to the to mount correctly (Figure 3). bare skull in order to rough out the After completing the basic facial structures (Figure 4). Foil grinding, cradles must be is used in order to minimize the fashioned in order to provide a amount of clay required. This helps to flat surface for the eye screens. keep the weight of the finished head A generous amount of Apoxie to a minimum. Sculpt is placed on the inside of the skull. The screens are Glue is used to securely attach covered in a layer of cellophane the foil to the skull. Our preferred to protect them and are pushed glue for this application is E6000 (see into the Apoxie Sculpt to make Resources). In fact, it is one of our favorite glues for most applications. It an exact impression. The screens is an industrial strength adhesive that are then removed and the provides about five minutes of Apoxie Sculpt is allowed to cure. working time — plenty of time to get Next, four holes are drilled Figure 5. Starting to add the clay. things positioned correctly before it to allow screws to be attached. begins to set up. It is also waterproof These will be used to hold the and paintable once cured. small springs that wrap around the screens and fasten them to the skull. Using the springs allows us an adjustable and removable method of attachment in case we ever need to pull the screens for maintenance, or if we decide to The transformation from a plastic skull to an actual repurpose them into another character. It is most important character’s face starts to take shape as the sculpting begins that the eyes are securely mounted in the proper position. (Figure 5). It is extremely satisfying to watch the Otherwise, they may shift and your character will be cross progression as the sculpting continues (Figure 6 and eyed! Figure 7)

Base Layer

Sculpting Features

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DIY Animatronics

Figure 6. The sculpting continues.

Figure 8. Pete was done with lightweight clay.

As mentioned, we currently use the two-part formula Apoxie Sculpt (see Resources). It provides an extremely durable finished product that can be sanded, drilled, tapped, and painted, and is waterproof. The effective working time is about two hours, giving you enough time to complete your work. It holds its form well during the sculpting process which allows you to sculpt large areas at once. It is not required that you do thin layers and allow them to dry before continuing one. This article is not meant to teach you how Figure 7. Nearing the end of the sculpting process. to sculpt. If you need some guidance on that, I would like to suggest that you check out Allen Hopps’ videos. His quality instruction on this process is fantastic (see Resources)! He is a master and is willing to share his vast knowledge on his videos. Another sculptor I admire is Ed Edmunds. Ed, along with his wife Marsha, own Distortions Unlimited (see Resources). Their company is extremely well respected within the animatronics industry. You may have seen them featured on the Travel Channel show, Making Monsters. The show is no longer on the air but you can purchase episodes online. Even though Ed makes his living selling his props and masks, he is still willing to share his experience with the rest of us. He has done many how-to videos on his methods that will surely Figure 9. Primer and sealer — vital help you improve your skills (see steps! Resources).

We tried several different products before discovering our current favorite. Pirate Pete (Figure 8) was sculpted using lightweight clay (see Resources). This allowed for a lighter finished product, but it is not as durable as our current choice. Pete has held up magnificently, but does require some extra care when handling. If the weight of your completed project is a primary concern, I would recommend this as a suitable product to use.

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Finish Work The end of the process is now within reach! The final sanding is carried out using ever finer grits of sandpaper. Foam sanding blocks are another useful tool for this. Care must be taken to not destroy the intended detail.

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DIY Animatronics The sanding process is necessary to eliminate imperfections to the sculpt without removing the desired design elements. If, after sanding, you are not satisfied with the finished product, you may reapply new layers of Apoxie Sculpt. It bonds to itself well, allowing you to add to and modify your sculpt until you are satisfied.

Painting Before we get to the painting, the sculpt must first be primed. I understand the desire to start painting, but it is important that this step not be skipped. We use the primer from Rust-Oleum which comes in a spray can and is easily applied (Figure 9). The head truly comes alive as the final paint is added. For this, Bob uses acrylic paint which is applied in layers. He begins with the darkest colors first in order to fill in any creases and crevices in the sculpture. Figure 11. Cheating a bit with the hair Figure 10. Gel stain gives a This allows those details to stand out as the attached to the hat. rich deep color. lighter colors are added. He continues to add colors until the head takes on the lifelike appearance he desires. the hard work that went into the head to be wasted! A combination of sponge painting and dry brushing techniques are employed during this process. A splattering effect can also be used by raking your thumb across a Besides properly finishing off the head, the addition of lightly coated brush or an old toothbrush. This will add hair fulfills another necessary role. The skulls we use have a freckles and age spots, increasing the realism. removable skull cap. It is important that this remain Some of our characters require a more “aged” removable so we have access to the inside of the head in appearance. We utilized this for the finish coat of our new order to maintain the mechanisms mounted there. The skeleton in the witch’s scene (Figure 10). For this, we used problem that arises is that we now have an unsightly seam Tandy Leather gel stain in saddle tan instead of paint (see running around the top of the head. The addition of hair or Resources). This product should be included in your a hat allows us to cover this seam from view, while still painting cabinet as you will find plenty of applications allowing us to get into the skull. Even when adding a hat where it will be useful. (like we did with Big Red), hair was still attached to the hat Finally, the head is sealed with a polycrylic from in order to achieve an authentic look (Figure 11). Minwax to insure it stays looking good. We do not want all You can purchase real hair that is already sewn into a cord. It comes in a number of different colors and can be purchased from many wig shops. You can also purchase a wig and cut portions from it as needed. Contact cement Monster Guts Three-Axis Kit — http://bit.ly/3axis (or E6000) can be used to attach the hair to the skull. Teensy Eyes — http://bit.ly/TeensyEyes If your head includes a moveable jaw and you are E6000 Glue — http://bit.ly/E6glue going to be adding a beard or are adding hair to a latex Lightweight Stone Clay — http://bit.ly/Stnclay mask, you may want to go with contact cement. It does Apoxie Sculpt — http://bit.ly/Apxsclupt provide some elasticity and may give a wider range of motion to your character. Allen Hopps Sculpting — http://bit.ly/Alsclp Applying eyebrow hair and a beard are additional areas Distortions Unlimited — http://bit.ly/DistUn where you can add significantly to the realism of your Ed Edmunds Sculpting — http://bit.ly/MLsculpt finished product. Since all of my characters talk, hiding the Tandy Leather Stain — http://bit.ly/Tndygel jaw joint really improves the end result. That is why you will Allen Hopps Hair — http://bit.ly/Alhair see many of our designs incorporate beards. Hitec Servos — http://bit.ly/HTservo The layers of hair are added from back to front,

Hair

RESOURCES

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DIY Animatronics we must install all of the mechanisms, mount the head to the body, and route all of the wiring (Figure 14). This includes the servo cables for the three-axis mechanism, as well as the wiring for the eyes (if we included them). You can minimize the eye wiring by powering them with a battery, but you will then need to provide a means to access the battery so it can be removed for recharging. You will also want to look at how to disguise the head mounting rod and wiring. You can fashion a neck from foam or an appropriately colored pair of pantyhose. Pantyhose come Figure 12. Pirate Pete with a full face of hair! in a variety of colors and will Figure 13. Big Red and his mutton chops. stretch to the shape you covering the attachment area of the layer applied before. need. The price is also right — especially if you get them The final layer is added without the sewn edge which from a dollar store. allows you to blend the final visible layer into the rest of the I use black spiral cable wire tube wrap to protect and hair. organize my wiring. This is a simple-to-use solution that Once you have added all the hair you want, you can allows easy access. then trim up the edges to get the final length you desire. The addition of all these sculpted features does, of If you still want to disguise the transition from the course, add weight to the completed head. This can cause sculpture to the hair a bit more, you performance issues with your can airbrush the hairline. This will internal mechanisms. To help blend it together even more, compensate for the additional providing a very natural result. weight, I replace the nod servo with one that has more torque. The final step in the process is Depending on how much heavier to coat the hair with Crystal Clear in the head is, I will go with either a order to keep it in the position you Hitec HS-485HB or a HS-645MG want. (see Resources). You can see how we utilized many of these techniques in our Pirate Pete (Figure 12) and Big Red characters (Figure 13). For a visual description of how Storing your completed head this process is done, again check and maintaining it is simple. Heads out Allen Hopps’ video on the built using this method are fairly durable, but they should still be subject (see Resources). Many of stored away with care between the techniques we use are taken uses. directly from Allen’s tutorial videos. I like to cover them in bubble Check out his other videos as I am wrap and store them in individual sure you will find his methods boxes. Even though the extremely useful in all your projects. temperatures are moderate where I live, I do keep them inside to avoid any wide temperature swings. Figure 14. Everything fits, but it can be a Upon completion of the head, Any required maintenance will puzzle!

Storage

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DIY Animatronics probably be centered on the mechanism and not the head sculpt. However, you may need to touch up the paint occasionally or add some glue to the hair to keep it in top notch condition. Make sure to retain some of the original paint for this purpose, and label it with the prop information.

Closing It Out

Tools N Tips How many times have you used that indispensable tool — the hot glue gun — and accidently applied glue to your fingertips? If you have not yet experienced this, do not feel left out as someday you will! This tip comes from my wife, Denice — a very talented crafter in her own right. She (like us) depends on her hot glue gun for many of her projects. And just like us, she has experienced the unpleasant sensation of burning her fingers while working with it! She passed along this tip to protect fingertips from the painful consequences of forgetting to treat hot glue with the required respect! Use silicone finger protectors from the office supply department (Figure A). They are inexpensive and come in sizes appropriate for your fingers and thumb. They will allow you to retain the dexterity of your fingers without allowing them to be burnt by the glue. I wish she had told me about these a long time ago! One important word of warning: Make sure when you wear them that the air holes are on the back of your fingers!

Moving forward, we are exploring new ways to design a skull and insert the three-axis mechanism to allow us to get rid of the seam line which is visible from the front. This currently needs to be covered with hair and does limit our choices for the final result. The design and development of animatronics requires a multitude of skills. It is nearly impossible to be an expert in all the necessary specialties used in their construction. That is why I encourage you to build relationships with others outside your field of expertise. This process — like many of our designs — is constantly evolving. As we discover new materials and develop better techniques, our finished products improve. You do not need to start with a full-faced sculpt. You can start by modifying a skull. Start with something small and build on it as your experience increases. I appreciate Robert taking the time to share his experience on this subject. His craftsmanship and attention to detail are a fundamental part of our success. Keep your eyes focused for the next project! Do you have a technique that works great that you would be willing to share? Then, visit the DIY Animatronics Forum at http://bit.ly/DIYfrm and join the conversation.

Figure A. Protecting fingers from the heat.

Your idea may encourage others to give this a try. If you have a subject you would like to see covered in a future article, please share that as well. I want to cover things that you are interested in and have questions about. Until next month, MAY THE PASSION TO BUILD BE WITH YOU! SV

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An ARDUINO CONTROLLED ROBOT ARM

A while back, I completed a MOOC (massive open online course) about robotics, which got me immersed in the amazing world of robot arms. Being involved for some time with tinkering and electronics, I decided I was going to build my own robot arm and try to implement everything I had learned in that course in the “real world.” decided to create an Arduino controlled robot arm that I could use as a platform to test all the theory that had been covered, and experiment with new ideas. I also wanted to be able to interface to the arm in as many ways as I could imagine with other devices (such as my laptop, smartphone, etc.). This would allow for future development, like adding robotic vision by means of a webcam.

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Let’s start first with some theory and basic concepts about robot arms.

What does “Degree of Freedom” (DOF) Mean Exactly? Surely, one of the first questions for those new to robotics or mechanics is: What does “Degree of Freedom”

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By Ricardo Caja Calleja

To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index.php/magazine/issue/2017/06.

mean? The DOF of a mechanical system is a specific mode in which said system can move; that is, a rotational or a translational movement. In the case of robot arms, rotational and translational movements are produced by revolute and prismatic joints, respectively. Most types of robot arms have only revolute joints, materialized with servos. To find out how many degrees of freedom a robot arm has, it is enough to just count the amount of servos since each servo provides one DOF (of rotational movement). So: Number of servos = Number of DOF. Easy!

Figure 1. Comparison of robot arm and human arm.

Parts of a Six DOF Robot Arm Why exactly six DOF? Because six DOF is the minimum that an arm needs to be able to reach to any point within a specific volume of space from every possible angle with its end effector (claw, manipulator, hand, etc.). Many industrial and hobbyist robot arms have six DOF. A robot arm can be compared with a human arm, which has at least six DOF. As observed in Figure 1, the robot arm also has a shoulder, elbow, wrist, and “hand” (end effector). Note that the shoulder and the wrist of the robot arm have two DOF each, as there are two perpendicular servos whose axes intersect in the joint. An arm with less than six DOF is classified as an “under-actuated” arm, whereas an arm with more than six DOF is a “redundant arm.”

How to Calculate Motion: Forward and Inverse Kinematics Let’s see how a robot arm can be controlled. There are two approaches to this: • Forward kinematics: The end effector space coordinates and orientation (from now on “pose”) are calculated considering a given set of joint angles. • Inverse kinematics: The joint angles are calculated considering a given end effector pose. It is clear that in most cases, we will need to bring the end effector to a specific pose and therefore calculate the necessary joint angles, which means that we will have to deal with inverse kinematics! Inverse kinematics is rather complicated compared with forward kinematics, and there are different approaches to solve this problem: • Algebraic solution: Very complicated equations in matrix form are needed.

Figure 2. Hardware block diagram.

• Numerical solution: Provides an initial guess of the joint angles and performs iterations to minimize the error. • Geometric solution: Uses trigonometry based on the robot arm geometry. Although the geometric solution may get very complicated for complex arms, a simplified model was my choice, as it was the easiest method to implement in the Arduino code. (More details on this will follow in the second article.)

How My Robot Arm Works The possibilities of controlling the robot arm from a PC/Raspberry Pi through the serial port (USB) are almost infinite: Matlab or Python script, Processing, Robot Operating System (ROS), Arduino IDE (integrated development environment; serial monitor), etc. The controller also interfaces with an Android/iOS device (tablet, smartphone) through Bluetooth, and can be controlled manually using a “control box” with rotating knobs as well. An important upgrade that I plan for the future (as previously mentioned) is the addition of robotic vision with a webcam mounted on the end effector and connected to a PC/Raspberry Pi. This way, the robot could recognize SERVO 06.2017

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Figure 4. Aluminium brackets.

Figure 3. Robot arm body.

different types of objects (by color and/or size) and grab them.

Construction of the Robot Arm The robot arm is divided into three main elements: • Robot arm body • Hardware (electronic controller) • Software

Figure 5. Robot arm base.

Construction of the Robot Arm Body

To build the robot arm body (see Figure 3), I purchased some servos on eBay that already included aluminium brackets so that it would be easier to connect the servos to each other, as well as to other elements of In the following sections, I will go through each of the robot arm (see Figure 4 for the aluminium brackets I these parts. made). These servos rotate up to 180 degrees and their maximum torque is 15 kg, which is more than enough. The two main challenges that I faced while building the arm body were the design of the base and the end effector. In order for the base to be able to rotate around Figure 6. Robot arm end the vertical axis and be stable enough to stand the effector. whole weight of the arm, I used four small wheels that I found in a DIY store (yes, the kind used for wardrobe doors!). Below the horizontal plate, there’s a micro servo fixed with brackets to the main base (Figures 5 and 6). This servo is not very strong, but for now it has done the job and its height is minimal, so the rotating base is kept as low as possible (for the overall center of gravity to be kept in a low position). For the base and end effector, I used

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Figure 8. Robot arm control box.

Figure 7. Controller PCB.

servos that can also rotate up to 180 degrees. Otherwise, the robot arm movements would be very limited. The end effector is rotated by another micro servo. As I couldn’t find a simple way of adding a gear mechanism to control the two “fingers” of the end effector with a single servo, I decided to use two micro servos for controlling the two fingers.

Design and Assembly of the Electronic Controller The controller consists of a homemade printed circuit board (PCB) and a control box that is connected to the PCB through a JST 2.0 PH eight-pin connector. The controller “brain” is a stand-alone Arduino chip (ATmega328) that processes all the analog inputs (from PC/Raspberry Pi/Android/iOS/control box) and provides the seven servos with the appropriate output signals (Figure 7). The power supply is provided in two independent channels of 5V and 6V for the Arduino chip (and other control elements of the PCB) and the servos, respectively. This is a very important fact to consider when we include servos or motors in our projects, as they usually present a very high current consumption. If they were directly powered by the same channel as the Arduino (ATmega328) chip, it could basically burn out when the servos get hungry! The control box has six rotating knobs which are used

to manually control every joint of the robot arm (base, shoulder, elbow, two wrist axes, and end effector); refer to Figure 8. The potentiometers attached to the rotating knobs produce a voltage range that is used as analog input by the Arduino chip. Depending on this input, the Arduino will command the appropriate output signals to the digital pins where the servos are connected.

The Controller Board You can see the list of electronic components needed to build the controller board in Parts List. To design the PCB layout, I used my old beloved friend, KiCad. (KiCad is an open source EDA software for Windows, OSX, and Linux.) I started to use it almost 10

Control Box Parts List • ABS enclosure 113 x 63 x 28 mm (a similar size is also suitable) • Micro JST 2.0 PH eight-pin female connector plug with wires • 6x 10K potentiometer • 6x 6 mm shaft potentiometer control knob

Controller Board Parts List • DC barrel jack adapter • SPDT slide switch • 4x 10 μF capacitors • 5V Voltage regulator (LM7805) • 6V Voltage regulator (LM7806) • Micro JST 2.0 PH eight-pin male connector plug • 2x Female pin header (1x6) • 3x Male pin header (1x6) • 28-pin DIL IC socket • Atmel ATmega328 chip (DIP28). If it does not have the Arduino bootloader installed, you will need to install it. • 16 MHz Crystal • 2x 22 pF Capacitor • 0.1 μF Capacitor

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Figure 9. Controller board schematics in KiCad.

converted into KiCad format. The first step to define the PCB layout is to draw the schematics in Eeschema — KiCad’s schematic editor (Figure 9). Then, a “netlist” has to be generated, which is a file that will be required by PcbNew (KiCad’s PCB editor module) to import the needed PCB components properly connected. For newbies, all this may produce more than one headache, but don’t panic! Once you’ve got a bit of practice, it becomes a rather smooth task. The upper part of Figure 9 shows the voltage regulators, which convert the input voltage (up to 12V according to the datasheet) into two voltage levels in two independent channels: 5V for the Arduino chip (and other control elements), and 6V for the servos. The lower part shows the Arduino chip with the interfaces (pin header connectors) to the following elements: • Control box (“Potis”): Micro JST 2.0 PH eight-pin male connector plug • Servos GND channel (“Servos_GND”): Male pin header (1x6) • Servos 6V channel (“Servos_V”): Male pin header (1x6) • Servos signal channel (“Servos_signal”): Male pin header (1x6) • FTDI232 USB to serial breakout board (“FTDI”): Female pin header (1x6) • HC-06 Bluetooth board (“HC-6”): Female pin header (1x6)

years ago in my first graduate job, and after trying other PCB software, I have always come back to KiCad. Although sometimes a bit tricky to use, it’s open source, the online community for solving issues is pretty big, and it’s always under continuous improvement. Plus, plenty of libraries from Eagle (such as those from SparkFun) are regularly

Figure 10. Controller PCB layout in KiCad.

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The Printed Circuit Board Once the whole bunch of components is imported into PcbNew, it’s important to make sure that the correct footprints are used. These next steps are my favorite: Define the board boundaries; place the components in the correct positions; and manually route the tracks. Since I didn’t intend to use double-sided PCBs, I had no other way but splitting the ground (GND) area into different “islands.” I later joined all the GND islands together, soldering cables and making a single GND region. In Figure 10, you can see the final PCB layout in KiCad. Once the PCB layout is ready in KiCad, there are several methods to make the physical board. In fact, this could make for a whole article! My preferred method is the use of a photosensitive Figure 11. Final PCB.

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Figure 13. Control box schematic.

Figure 12. Final PCB with components soldered.

Figure 14. Control box connections.

Assembly of the Control Box For the electronic components needed to build the control box, see the Parts List for it. The schematic of the control box is shown in Figure 13. It simply takes the GND and 5V signals from the controller board through the Micro JST 2.0 PH eight-pin connector (pins 1 and 2, respectively), and provides the output voltage from the potentiometers (pins 3 to 8). For the control box, I simply used a small stripboard to solder all the connections of the potentiometers on to it (Figure 14). Figure 15. HC-06 and FTDI232 USB to serial breakout board.

board with UV light exposure; NaOH (caustic soda) + H2O (water) as the developer solution; and H2O2 (hydrogen peroxide) + HCl (hydrochloric acid) as the etching solution. I managed to get a pretty good result this time (Figure 11). After drilling the holes with a Dremel using a 3/64” drill bit, it was time to solder all the components. Figure 12 shows the PCB with all the components soldered.

FTDI232 USB to Serial Breakout — HC-06 Modules The robot arm controller interfaces with the PC/Raspberry Pi through the serial port (USB) by means of an FTDI232 USB to serial breakout board, as well as through Bluetooth with an HC-06 board (see Figure 15). These modules are connected to the six-pin female headers of the controller. At first, I wondered if it would be possible to have SERVO 06.2017

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Final Thoughts and Considerations

serial communication on more than two pins (RX, TX) of the Arduino chip. With the function SoftwareSerial library, it was easy peasy! Declaring the digital pins where the FTDI chip or the Bluetooth module is connected creates a virtual serial port/UART. So, now the FTDI232 USB to serial breakout board is connected to pins RX/TX, and the HC-06 board to digital pins 10 and 11. I’ll have more details on this in the next article, where I will dive into the software.

After being involved for some time with robotics, I’ve learned some important lessons. First off, since we’re working with servos and elements that move, one has to be extremely careful with their range of movement, making sure that there’s always enough clearance around them to allow their free movement. Otherwise servos, cables, and structural parts of the robot or even objects around it may get damaged. Or, you can even get your fingers injured! Also make sure that you define the appropriate initial servo positions in your code. It happened to me when all the initial servo positions were set to zero degrees. After powering up the controller, the arm made abrupt movements hitting everything around it! Second, try not to manually rotate servos when they’re not powered, as it may cause damage in the gears — especially if they’re made of plastic. Furthermore, if your budget allows it, go for servos with metal gears. Last but not least, be careful with the polarity of servo connections! Connecting a servo with the wrong polarity will surely damage the servo electronics.

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In the next article, we will actually see my robot arm moving! I will show how I defined the geometrical solution for controlling the robot, as well as how it was implemented in the Arduino code. I will also show how to interface the robot arm with a PC/Raspberry Pi through the serial port (USB), as well as with an Android/iOS device by means of Bluetooth. Stay tuned! SV

Resources My blog funwithcables.wordpress.com

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| www.expresspcb.com

Arduino official website www.arduino.cc KiCad official website kicad-pcb.org

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The Gortinator A Walking Robot Made from PITSCO/TETRIX MAX Parts This is a project I did for the sheer fun and challenge of it. I have made smaller two-legged walkers in the past; one of my own design from Minds-i parts and the Parallax Toddler. Using TETRIX MAX parts, I could make a very large impressive looking two-legged walker. It was a challenge! The basic design for this type of walker comes from an old-time robot created in the UK called Bigfoot. I was originally inspired to do these two-legged walkers after getting the Toddler. Parallax does not make the Toddler robot anymore, but there are a lot of them still available on eBay.

By Carol Lynn Hazlett To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index. php/magazine/issue/2017/06.

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Kits used to make walker.

What I Did

Feet showing one foot lifted.

Leveling hubs on ankles.

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The hardest part was going to be the feet, so I started there. The robot must be able to tilt its body to one side and lift its other foot off the floor so it can move the foot forward. The foot must stay level with the floor, so the ankles on the robot need to have movement in three directions, yet be strong enough to hold the robot steady while balanced on one foot. I put hubs on the bottom of the legs to allow for the lateral movement to keep the feet level when the legs move forward and backwards. Mounting the hubs on a long axle gave me the rotation needed for the body tilt to shift the robot’s weight. All of these are then attached to the foot plates which make the feet. About halfway between the feet and hips are crossbars on the legs to attach to the servo to move the legs back and forth. These also need to be able to stay level when the legs move, so they are attached with rotating hubs. The servo for moving the legs back and forth is mounted to the bottom of the body between the hips, and has a crossbar connected to the servo horn which moves back and forth attached to crossbars on the legs. The bars which move the legs are slightly canted together at the back to increase torque. The legs are then attached with rotating hubs to the hips which keep them level when the legs are moving back and forth. The body is secured to the inside of the hips and slightly canted backward to help with the balance of the robot. I put the battery pack on the back for the same reason. With the arms and grippers up front, the robot needs the added weight in the rear.

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Crossbar at knees.

Hips from side.

TETRIX MAX has a humanoid type robot with a moveable arm, but I decided to build my arms differently so they were closer inboard to the body; again, to help with balance. I tried the other way first, but the robot was too tippy. Almost everything on this robot was remade and redesigned many times! To tilt the body, there is a servo on the front of the robot attached to the lower part of the body that pulls up the foot on one side to make the robot lean over. The balance here is very crucial and once I had the build of the robot balanced overall, the speed and angle of the servo decides the balance point.

Servo for making legs stride.

Servo to tilt body. One of the more difficult parameters to determine was the servo speed. If it pulled up too fast, the momentum would tip the robot right over. If it was too slow, it would not lift the foot high enough to get it off the floor. Getting the right angle for that servo was just a matter of trial and error. Of course, if I changed one thing I had to change everything. The walk sequence is easy: lean right, left foot forward; lean left, right foot forward. Between the mechanics and refining the program, it took many tries to get it right. I added a servo to the head to make the robot capable of picking an open path for itself. When it encounters an obstacle, it swivels its head and based on the servo position SERVO 06.2017

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Close-up of arms and grippers. Swivel head.

Close-up of leg stride servo setup.

Does this make my butt look big? Tetrix www.tetrixrobotics.com

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My YouTube Channel https://www.youtube.com/ watch?v=8TZN_nXCRj0

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where it sees an open path, it turns in that direction and then walks forward. If it cannot see an opening (such as walking into a corner), it will turn around 180 degrees and head out of where it is. This behavior gives it a more appealing look that seems as if it is actively thinking on its own. The servo is programmed for five positions: left, mid left, center, mid right, and right. When the Parallax Ping))) sensor sees an open path, the servo’s position is fed back to the microcontroller and the proper turn is picked from the subroutines. This is where a lot of the work for this robot comes in: all the programming and part tweaking to make reliable turns and moves. I have not decided yet what to do with the grippers and movable arms, but for now they add a lot of charm to the robot.

The Brains

The Prizm does have its own set of commands for the servos and sensors, but I found them to be very easy to use and quite intuitive. It is a little easier to program this robot than using straight Arduino C. The only drawback is I would have liked to be able to program it wirelessly.

In Summary There are several videos of it on my YouTube channel and my Facebook page. It is hard to describe all the various joints and mechanisms on this robot in words, and still pictures can be confusing to try and figure out what you are looking at. So, I definitely recommend you view the videos of it. This has been a very rewarding and enlightening project which I both enjoyed tremendously and am glad it is completed. Whew! SV

The TETRIX MAX kit I have uses the Prizm controller made by PITSCO. It is based on the Arduino Uno and has a library of its own. It is simple to set up and use. Plus, since so many of us have used Arduinos, the learning curve is very easy.

Crack the Code with the TETRIX® PRIZM® Robotics Controller TETRIXrobotics.com/PRIZM

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Brushless Motor Basics

The Multi-Rotor Hobbyist When browsing around drone forums and talking with other hobbyists, I often find arguments about the brushless motors we commonly use on our aircraft. It’s not surprising given the wall of constants and graphs presented in the datasheets for these motors. This month, I’m going to attempt to clear up the topic by introducing the fundamental workings of the brushless DC motor (BLDC; Figure 1), and help you select the right motor for your next project.

By John Leeman To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index.php/ magazine/issue/2017/06.

Figure 1: A typical BLDC used on a mid-sized quad rotor. These can now be picked up for under $20, and are available with right and left handed thread prop nuts and attachments.

Introduction

Motor Dictionary

Given that choosing the correct motors and propellers is essential to even getting in the air — much less creating a well-tuned quad — it’s an important topic to understand. If you need a review on propeller design and balancing, check out the December 2016 issue of SERVO. The problem is that you can’t just choose the motor and propeller independently, but need to think about their performance together. Otherwise, you may find yourself with motors that overheat, quads that barely get off the ground, or quads so over-powered that they are impossible to control. While some of the micro-drones do used brushed motors (like the CX-10 from the March 2017 issue of SERVO), quads of any size generally have switched to using BLDC motors for reasons of efficiency. There are a plethora of resources available on both brushed and brushless motors. If you really want to dig into choosing the right motor for any project — not just your aircraft — check out the book, “Motors for Makers: A Guide to Steppers, Servos, and Other Electrical Machines” by Matthew Scarpino (http://amzn.to/2mjK2En). As you’ll see, there are a lot of rabbit holes to go down, but once you understand the basics, it all seems much more manageable.

To get started, we need to get a common set of lingo with the engineers designing these motors. Design specifications generally talk about force, torque, speed, and constants like KT and KV. Once these terms are defined, the datasheet begins to look a lot friendlier than it did before! Force is any influence that can modify the motion of an object. Think about flying our racing quads around; you can imagine there are many of these forces at play — several of them rather large. Going back to high school physics, we remember that Newton has some fundamental laws about the motion of bodies. The second law is particularly interesting because it states that the force on an object is the product of its mass and acceleration: F = ma. In the metric system, we would write down the mass in kilograms and the acceleration in m/s2, giving us force as a kg m/s2, or a Newton. Imagine that your quad weighs 750 grams (0.75 kg). Gravity is pulling it towards the center of the earth with an acceleration of 9.81 m/s2. This means the quad experiences F = 0.75 kg * 9.81 m/s2 = 7.36 N of force downward. To hover, we must produce an equal force of 7.36 N upward; more to climb, less to descend. To calculate the net acceleration of our quad, we add up all of the forces —

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Figure 4: Converting between common torque units just requires multiplying by the values shown.

often with the aid of a “free body diagram” (Figure 2). Torque is another tricky one — commonly misused and further muddied by changes in terminology based Figure 2: A free body diagram of some of the forces at play on a quad. on the region of the world you are discussing it in. We’ll Gravity pulls down (green), the propellers generate lift (purple), and the rotation of the propellers introduces torque (red). For proper flight, stick with the US usage of torque, but acknowledging these must all be understood and balanced. that it may be referred to as moment or moment of force, depending on which datasheet you pick up. Similar to how acceleration is the rate of change of velocity, torque is the rate of change of angular Figure 3: A moment arm momentum. A higher torque can be thought of as model. Moving the weight more “twist” that can be applied to an object. twice as far from the pivot on the left doubles the The big catch comes when we look at the torque. When torquing bolts moment-arm formulation of torque: τ = r F. Imagine down, we often talk in “foothanging a 1 kg mass on the end of a shaft attached pounds,” or the torque to the wall (Figure 3). Intuitively, we know that if we exerted by that many pounds at a distance of one foot hang the weight further out on the shaft, the shaft from the center of rotation. will need to be stronger and better affixed to the wall. This is because the torque (τ) is proportional to often specify torque in ounce-inches, pound-feet, or any the radius (r), or distance from the center of rotation. other number of annoying units. I’ve included a conversion If we hang the mass 1 m from the center, the torque is table for the common units you’ll find on quad motor τ = 1 m * (1 kg * 9.81 m/s2) = 9.81 Nm. If we move the mass to 2 m, the torque doubles to 19.62 Nm. datasheets (Figure 4). To make things a little more confusing, manufacturers The last fundamental quantity we’ll discuss is speed.

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Figure 5: The current-torque relationship of a motor can be modeled as a straight line. The intercept represents the no-load current and the slope is the constant KT.

Linear speed is something we are all pretty familiar with. We drive our cars at a given speed in miles/hour or kilometers/hour. Rotational speed is a bit trickier, though. As we discussed in December when talking about propellers, the linear speed of the propeller depends on where on the propeller you look. The further from the center of rotation you are, the higher your linear speed must be to stay in one piece. For rotating objects, it is much more convenient to talk about the angular speed, or how many degrees per second the object rotates. (True physics based folks and many engineers will talk in radians per second as well.) The most convenient for dealing with our hobby motors is revolutions per minute (RPM). It’s nice and intuitive, and easy to measure. For us, the important thing is to make sure we can get our propellers to sufficient angular velocities to produce enough thrust for us to fly. With some terminology out of the way, we can finally talk about the coefficients KT and KV. These constants that are seen in datasheets are argued over on forums all of the time. They describe the relationship between current and torque (KT) and voltage and angular velocity (KV) of a motor. For most DC motors, the torque output by the motor is roughly linearly proportional to the current supplied (Figure 5). If we take measurements and fit a line, we end up with two parameters that define the line: the slope and the yintercept. The slope of the line represents the change in torque per change in current (Nm/A) and is KT. The intercept of the line is the no-load current; how much current it takes to spin the motor with no external load applied. We can make a similar style of plot for the applied voltage and the rotational speed of the motor (Figure 6).

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Figure 6: The speed of rotation and the voltage are also linearly related for DC motors. Here, the intercept is the voltage loss in the windings at no rotational speed; the slope is the constant often seen on datasheets — KV.

The slope of this line represents the change in angular speed per volt (RPM/V) and is KV. The intercept of the line is the voltage loss in the armature of the motor. A neat thing about KT and KV is that they trade off. I won’t go through the proof of this, but it can be shown that the product of the two quantities must always equal a constant: KTKV = 1352.36. In datasheets, you’ll generally just see the KV value, but can calculate KT if you need it. The important ramification of this is that no motor can be good at converting current into torque and voltage into angular speed. It can be okay at both or better at one, with a reduction in the other. This makes selecting the right motor for your particular application even more important!

BLDC Background While the idea of multi-phase motors has been around for a while (the three-phase system was independently invented by four different researchers in the 1880s), the idea of a multi-phase DC motor was not really possible until semiconductor technology advanced in the 1960s to allow rapid switching of large currents. In 1962, Wilson and Trickey published a paper entitled, “D.C. Machine with Solid State Commutation” with the American Institute of Electrical Engineers. Their idea was to use an electronic based system to switch the direction of applied current to the motor coils instead of the mechanical brush based commutator system traditionally used with DC motors. The main advantage of electronic commutation is that there are no mechanical brushes and contacts to arc, wear down, or cause reliability issues. As we’ll see momentarily, the motors are also synchronous, meaning that they rotate in direct correspondence with the way the power is applied

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Figure 7: This old E-flite motor has seen better days. It was involved in an unfortunate crash that bent the shaft and filled it with mud.

Figure 8: Removing the set screw indicated by the arrow and the e-clip at the bottom of the motor allows the rotor and stator to be separated. This motor took some coercing as the shaft was tightly rusted to the inside of the bearings.

— something that had previously been limited to AC motors. It turned out the brushless design also produced a more efficient motor. In other words, the ratio of power out to power in was higher. BLDCs found their homes in floppy drives, disk drives, and other high reliability applications. The technology remained largely unchanged until the 1980s when permanent magnet technology improved. Since then, a lot of research has taken place to optimize the design, but the base technology has stayed the same.

Parts of the BLDC For the purpose of actually showing you the parts of a BLDC, I dug through the junk boxes to find a motor that was involved in an unfortunate incident and suffered a badly bent shaft (Figure 7). By removing a set screw (Figure 8) and e-clip, it is possible to take the motor apart and really see how it works. If you have a junk motor, I highly recommend following along. The style of motor commonly used on multi-copters is the “Outrunner” style. The shaft of the motor is attached to the rotor, which is on the outside of the motor. Spin the shaft and notice how the whole outer housing spins. There are “Inrunner” motors that look more like conventional brushed DC motors, but are still brushless and electronically commutated. Inrunners generally have fewer “poles” than

Figure 9: Inside the rotor are 14 magnets with alternating polarity. These are very strong and will snap onto the stator with enough force to hurt. Be careful and keep away from your magnetic storage media!

an Outrunner, and cannot produce as much torque as Outrunners. To make up for this, most Inrunners operate at very high speeds, with KV values from 7,500-10,000. They are a more efficient design, but require a gearbox to operate loads like propellers, and are therefore not used on many quad designs. Taking apart our Outrunner motor, we find there are two main pieces: the rotor and the stator. Here, the names actually make sense. The rotor is the rotating part and the stator is the part that stays fixed. Spend a few minutes looking at the parts and playing around. The rotor is the outer shell in this configuration. It is lined with permanent magnets whose polarity alternates as you go around the circumference (Figure 9). At each SERVO 06.2017

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slots is not a multiple of the number of poles, this is a fractional slot motor. Motors with a number of slots that is a multiple of the number of poles are called integral slot motors. The windings of Figure 11: Three-phase motors can be wired in the motor are the wye or delta configurations (so named for Figure 10: The stator of this motor has 12 slots, or their shape). In our case, the controller will hook grouped together into coils. Color has been added to show the three sets of up and work identically for both configurations. three sets of four coils four coils configuration. You can also see the upper Each coil in this diagram represents four slots on (Figure 10). bearing at the center of the stator; another bearing the stator that are connected together. was pressed into the bottom of the motor housing. By applying current in both a “positive” and “negative” direction to each set of windings, there are six possible states of the slots. The controller handles this (more on controllers Figure 12: Most motor manufacturers will use some form of this “standard” naming next month) and creates a wave-like convention. The number of slots or poles are sometimes omitted, but the diameter, height, magnetic field that is traveling and KV rating are commonly included. around the stator. The magnetic poles of the rotor are compelled to follow this magnetic wave, and the motor is running. The coils of the motor can be connected in either a delta or wye configuration (Figure 11). These are the traditional configurations of threephase AC motors as well. The design decision really comes down to a set of tradeoffs between wire gauge, weight, number of turns of wire required, and the number of control phases used. For our three-phase motors, the hookup to the Figure 13: The Amazon product pages often have a lot of useful controller will be exactly the same no matter the information. It really is amazing that these small motors can pull over 20A each from our multi-rotor’s power system! exact configuration of the motor. location, there is a magnet called a pole or magnet pole. In this case, the motor is a 14 pole motor. In general, the more poles a motor has, the more torque it can produce. The stator is the inner portion of this motor and is made up of multiple coils. Each coil position is called a slot or stator pole. Our motor has 12 slots. Since the number of

Picking Your Motor If you search online for guidance about how to pick the right motor for your quad, you’ll find a mix of strong opinions and pages that say to simply look up the thrust for a given propeller on a given motor. In an ideal world, we

Figure 14: Manufacturer’s data tables will often recommend battery and propeller combinations for a given motor. Using larger propellers could lead to overheating of the motor unless the pitch is reduced as well.

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know that the desirable thrust-toweight ratio for a garden variety quad is 2:1. We weigh the quad, multiply by the thrust-to-weight ratio, and divide by the number of motors. We then go to a manufacturer’s webpage and look at their datasheets. Ideally, a variety of propellers have been tested on each motor and the data are available. While the above story sounds nice, it’s really just a story. Motor data is often scant at best and there is some experimentation required. There are rules of thumb around, but I often find that the community has videos of motor tests on YouTube that have enough information to estimate if a given motor and propeller combination is suitable for your quad. The first thing to consider is what kind of aircraft you are trying to build. For high performance quads that will be racing, doing aerobatic maneuvers, and so on, it’s better to stick with swinging smaller propellers faster. This means you’ll be interested in motors with a high KV value — the loss of torque conversion capability is not as much of an issue as pure propeller speed. These motors are generally less efficient, but efficiency is not the goal. To create a quad for aerial photography, sensor deployment, etc., we generally want to swing a larger propeller more slowly. We don’t need incredible accelerations or speeds, but we desire a stable and long running platform. Buying a lower KV motor will give you more torque and utilize the power more efficiently. Will you be operating at low angular velocities often? Integral slot motors have a tendency to experience cogging at low speeds. This means that the magnet poles line up with the slots, almost stop, then jump to the next position. This herky-jerky motion is undesirable and is greatly reduced by using a fractional slot motor. Looking for motors online can be confusing at best. Generally, there are

some pieces of the “standard” naming scheme (Figure 12) used. More often than not, you’ll end up digging through the seller-provided specs (Figure 13), but they may not even be present. Often, a search for the datasheet yields a bad photo of a table from somewhere that is somewhat helpful (Figure 14). With the smattering of information, it’s enough to make an informed decision, but is an area manufacturers really need to improve upon. Personally, I’m considering building a test stand to characterize motors which I would, of course, share with you here!

Closing Thoughts With a little understanding of the design of the BLDC motor, you are far ahead of the pack in actually choosing the correct motor for your quad. With the correct choice, there should be no excess heating problems, thrust issues, or other show stoppers. Experimenting with different motors is a fun and relatively inexpensive way to upgrade and change your quad’s performance. Personally, I’m a big stable quad person wanting to fly routes to collect data, so I’m generally on the lookout for low KV motors to swing big propellers. Whatever your interest, there is a motor manufactured to fill that need. We mentioned above that running a BLDC is not as simple as hooking power up like with a brushed motor. Next month, we will dive into the world of electronic speed controllers (ESCs). We’ll get our hands dirty “Flashing” new firmware onto a popular ESC and playing with its performance. Until next month, fly safely. SV

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a n d

g{xÇ Now

by Tom Carroll [email protected]

Human/Robot Interaction with the Elderly The design of companion robots to interact with and assist elderly persons in their daily living has been one of the many goals of robot designers for several decades — myself included. The major factor that has been the stumbling block for developers of a viable personal assistant robot for the elderly is the physical human-robot interaction factor.

Disabled Veteran’s Physical Assistance Needs Many robot designers have been inspired by disabled military veterans who have returned from the field of battle with permanent injuries that have made life very difficult for them. This group first inspired me as one of my sons was severely injured in the Navy, and is finding the rest of his life to be a great challenge. He has several types of injuries and disabilities that are entirely different from other veterans he meets at the several VA hospitals where he is being treated. The more I studied disabilities, I found that there is no specific robot design that would be applicable to all or even a smaller number of disabled veterans as their needs are so different. Leg injuries, arm injuries, and other body injuries present vastly different assistive needs. Of course, this applies to all persons who have physical disabilities, not just military veterans.

Elderly Person’s Physical Assistance Needs When I began to study the needs of the elderly several decades ago, I went to several elder care facilities with both minimal care private rooms, as well as more intensive 24 hour nursing assistive care. I spoke with

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some of the residents — both bedridden and those who are ambulatory and able to travel outside the facility. Even the few with whom I visited in their private homes had needs similar to the others. As one could imagine, when I showed them a drawing of a proposed robot that I was designing to assist seniors in living independently, their responses varied from “I don’t want any machine taking care of me,” to “Wow, a robot to assist me in my daily activities would certainly be a lot cheaper than what I pay for this place” (a nursing home). One man told me, “I have a car back at my home that I can’t drive anymore. I’ll sell it and buy me a robot. Then, I can go back to my house.” I quickly realized that most of the elderly persons I interviewed were not disabled; their physical capabilities were just not what they used to be. Unlike the truly disabled veterans I interviewed who had many different physical needs, the elderly population pretty much needed the same physical assistance in their daily lives. They have physical limitations, not disabilities. The muscles they use to arise from a bed, chair, or toilet are not as strong as they were in their youth. (I can attest to that fact myself!) I began to realize that a single style of personal assistant robot might be very useful in allowing seniors to

retain their independence in daily living. Most people have great pride in being able to do the same things that they’ve always been able to, and it is a hurtful shock to their self-worth to be told they must now rely on others to attend to their daily needs. Hiring people for this can be frightfully expensive. A personal home service robot could do most things for them at a far lower cost. Last month, I discussed security and police robots and their different forms. These were human size for the most part, but were not capable of assisting humans in a physical sense. Before delving into the features and complex robotic movements needed to assist a person, I’d like to step back a few decades to discuss what early developers felt was needed in a home robot. Let’s take a look at some ‘classic’ larger home service robots of the last few decades that seemed to have a lot of capabilities for the time.

The First of the Early Home Service Robots: the Hubot A dozen years ago, I wrote about two very interesting larger home robots “of yesteryear.” One was called the Hubot. Smaller robots such as the TOMY 2000, the Androbot series, the RB5X, and the Heath Hero series were very interesting and functional for their time. Most of these were a bit

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Advances in robots and robotics over the years. To post comments on this article and find any associated files and/or downloads, go to www.servomagazine.com/index.php/magazine/issue/2017/06.

Figure 1. Hubot by Hubotics in 1984.

too small to be very useful in Figure 2. A photo from a newspaper showing Hubot in assisting a human other a kitchen. than bringing them a prepoured drink. The Hubot stood out ports for peripherals. The computer from the crowd mainly because of its was divided into two sections: one to size and capabilities. control the robotic systems and the It was developed in 1983 by Mike other its functions. Remember, this Forino, and made its debut at the was in the days when a PC cost Consumer Electronics Show in January upwards of $10K in today’s money. 1984. Forino’s earlier experience was As I noted in my previous articles, with industrial robot systems. He some of the more interesting formed the company he called peripherals were a voice synthesizer Hubotics to produce the 45 inch tall with a 1,200 word vocabulary, a 110 pound robot shown in Figure 1. rotating ultrasonic transducer Forino felt that his fairly large “Obstacle Sensing Processor” collar to Hubot could be viewed as a serious detect walls and objects, a digital home robot, as it was not designed clock, and a battery charger. It was for educational and/or hobbyist uses. priced at $3,495 for upscale Though some joked that it was little customers. Not bad for the time when more than a TV on a mobile platform, the first “robots” were making the the body shell was well designed and scene. it stood high enough to be able to Forino added other optional interact with people (Figure 2). ‘expansion’ features such as a sentry A TV was normally used as a system package; verbal command via monitor for the SysCon computer with the computer or through joy sticks; three Zilog Z80A microprocessors. The and an Atari 2600 video game computer had 128K of RAM; 42K of console. An automated charger ROM; an 80-column by 24-line display; system allowed the robot to go a 5-1/4” disk drive; and a 64-key straight to its ‘dinner’ location when detachable keyboard, plus several I/O hungry. He also offered a vacuum SERVO 06.2017

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Figure 3. Arctec Gemini autonomous robot of 1985.

cleaner package. The feature that appealed most to me was an arm and functional hand they had planned, though I never saw it in operation.

Another of the Early Home Service Robots: the Arctec Gemini Shortly after the Hubot, Arctec Systems in Columbia, MD introduced the Gemini ‘autonomous robot’ in 1985. “You will think Gemini is really alive,” touted their brochure. The robot is shown in Figure 3. I have one of their catalogs that features an ‘assembled and tested’ unit at a cost of $6,995. This was in 1985. An average new car cost $6,495 and a yearly salary was approximately $12,747 in that same year. You really had to want this particular robot to purchase one — especially since you could get two Hubots for about the same price. You could save $3,400 and build a Gemini yourself, or buy the Geminix Experimenter kit for $2,350, which was a Gemini minus the shell. Figure 4 shows the internal components with descriptions of each part. I had a chance to play with a

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Figure 4. Internal components of the Gemini.

Gemini back at one of the RI-SME shows. It was amazing. Standing about 48” tall with a 20” base, it was similar in size to the Hubot but quite a bit lighter at 70 pounds. It used three Rockwell 65C02 microprocessor boards; a 64K ROM; a 56K RAM processor running at 4 MHz for the main computer; and two others running at 1 MHz for the voice

processing and motor control. There were two other processors for the wireless IR keyboard and remote control. A 40x8 character LCD display allowed programming directly from the detachable keyboard. It used nine Polaroid electrostatic ultrasonic transducers for distant object navigation and wall detection. These single-port transducers were quite popular at the time, though you could get quite a shock from the driver board if you weren’t careful. Gemini also used IR emitter beacons that could reflect off of doorways and specific targets where IR reflective tapes were applied. It could detect its charger base with this system as well. Autonomy was not the only way of control as a user could employ the cordless keyboard to deliver commands, as well as speech commands via the voice recognition system. An RF link to a separate computer was also available. A joystick could be connected via one of the three ports such as a common RS232, dual parallel, or even the old classic Centronics printer port. Arctec was unique for the time in that it encouraged hacking of the robot. The robot had a beefy power supply that was able to drive various additions. Adding peripherals and even arms were advocated, and these ‘hacks’ were to be distributed amongst the owners. The Gemini stood alone as a serious experimenter’s robot, but the very high cost kept its numbers too low for successful large-scale marketing.

Samsung’s iComar of 2001

Figure 5. Samsung's iComar robot never gained popularity.

Looking a bit closer to recent times, Samsung developed a small household robot — not as a physical helper in the house, but to help members of the household to communicate with the outside and control systems within the house. iComar stands for Internet Communicable Avatar Robot and was created in 2001. Shown in Figure 5, it was dubbed an ‘edutainment robot.’

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It was able to perform a lot of functions, despite its small size of 24 inches tall (60 cm) and 22 pounds. iComar was able to navigate a household autonomously and avoid obstacles through its nine sonar ultrasonic range finders. It interacted with its user through piezoelectric touch sensors. It also could perform simple tasks such as playing music upon verbal command. It could be scheduled to perform tasks such as turning lights and various appliances on before the owner arrived home. Remember, this is before Samsung and Apple had the true smartphones of today that a person can use to perform the same tasks. iComar’s Internet connectivity allowed live two-way video chats facilitated through its LCD screen and built-in camera, though the video image quality left something to be desired. It also served as a home security robot. It sent text messages to the home owner in the event it detected unusual activity around the house, and it had an internal alarm system. iComar used a Pentium MMX 266 MHz CPU with Internet

now sells for $3,000. Luna has been in the news for several years as Kickstarter funds were being gathered. It caught my eye for this article due to its style and height. Nikgohar has stated: “Luna can keep an eye out on the elderly living on their own, and help them to remain independent. Luna can be an invaluable medical assistant, reminding patients to take their Figure 6. The Samsung iComar with a young girl. medicine, assisting nurses by fetching items, or carrying things connectivity and had speech from room to room, or facilitate recognition for robot control. bringing a specialist to a patient’s Using its camera for visual bedside (telepresence) for urgent recognition and its microphones for medical care.” sound detection and communication, “Luna is the first human size it was capable of moving around personal robot designed for everyday autonomously and allowed users the practical use,” Nikgohar stated. “App ability to command it to do the store, lots of features, and a great certain tasks such as controlling personality. Since our founding, our household appliances and lighting. mission is to bring robots to the The image in Figure 6 gives a hint of masses. We believe that robots and why it did not sell as well as Samsung humans can live and work in harmony had intended, and ended up being together. That’s why we made Luna. more of a toy than a useful household Luna is a personal robot designed for appliance. everyday practical use. She is a powerful platform capable of an increasing universe of apps and services through an app store model. Luna is the first evolutionary step in a near future where robots become a Figure 7. Luna Luna — a five foot tall 65 pound normal part of everyday human life.” robot from Nikgohar desired three aspects in Robodynamics. telepresence robot shown in Figure 7 — was developed by Fred Nikgohar the robot’s design: expandability via and his team at Santa expansion ports and RF (Wi-Fi, Monica, CA based Bluetooth, and 3G/4G); fully RoboDynamics. The programmable via ROS; and most of sleek robot’s shell was all, be affordable. Luna has a high designed by the resolution eight megapixel camera Pasadena, CA based featuring zoom capability, a quality Schultzeworks and has speaker, and three high quality an eight inch LCD microphones. The ‘arms’ are noncapacitive touchscreen. functional tubes, but can be It has a dual core positioned for simple tasks as seen in Atom (2 GHz) processor Figure 8. running on ROS with 8 The robot’s batteries allow a full GB of Flash storage — eight hour day of operation, and the expandable up to 32 drive wheels contain 10-bit wheel Gigs — and a powerful encoders for precise navigation and nVidia 94000M hybrid odometry. A PrimeSense 3D camera graphics card. Starting system assists in navigation around a Figure 8. Luna's arms are out at $999 in its early home. The open source platform positioned manually to carry Kickstarter period, it allows developers to build software a tray of glasses.

One of the Latest Human-Sized Robots: RoboDynamics’ Luna

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Figure 9. The single handle is a great idea, but it's still a bit heavy.

for additional robot capabilities. According to Robodynamics, this means that the functions of Luna are only limited by the inventiveness of its users. I’d like to see someone develop true mechanical arms, but the narrow upper body does not allow for any substantial motors for driving such things. Luna seems to be very sensibly designed. The photo in Figure 9 shows a built-in handle for carrying the 65 pound robot, though it seems a bit heavy to be carried around onehanded.

Figure 10. Fraunhofer Institute's Care-O-Bot 3 elder care robot.

same time, it can set up communication with an emergency center who can talk to the user by video telephony using the screen, speakers, and microphone of the robot.”

Fraunhofer Institute’s Care-O-Bot 3

What is Acutally Needed in an Elder Care Robot?

One of the most impressive robots designed to assist seniors in their homes or even a care facility is the Care-o-Bot by the Fraunhofer Institute in Gremany. Shown in Figure 10, the $275K (US) robot is very capable and well-designed as an assistant for the elderly in their homes. Their site states: “The third generation of the Care-O-Bot development series is characterized by a product-like system design and provides the potential to apply manipulating mobile service robots in everyday environments. The use of industrial components approved in daily practice ensures the dependability of the system.” “In emergency situations, quick and target-oriented support is essential. When, e.g., the user has fallen, Care-O-Bot 3 is able to move towards the fallen person. At the

As usual, I like to begin by covering a few relevant robots from the past that seem to have the capabilities that I’m discussing, and then work up to the present time. In this particular case, none of the above robots truly possess all of the needed capabilities for assisting a person in their home (certainly not an elderly person). There are many simple devices that can remind one to take a specific pill at different times of the day. Simple pendants worn around the neck can allow a person to call medical or police authorities in an emergency. Other devices can let a person make a call or receive a phone call strictly by voice commands. These days, Skype is readily available for smartphones as well as laptop and desktop computers, so we do not require a mobile robot in order to visually connect with a friend,

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doctor, or anybody with an applicable computer and camera on the other end. Amazon’s Echo series with the friendly Alexa voice app is extremely popular after less than two years. Talking robots have been around for awhile, but table-top devices such as these can certainly fit the bill for verbal communication with Alexa and Google Home. Cortana has long been available for our computers and Siri for our iPhones. However, if we add conversational ability to a mobile home service robot, does that make it applicable as a true robot to allow seniors living independence? Today’s home service robots seem to have some amazing capabilities with all the advances of artificial intelligence and verbal communications via the cloud. They can perceive you by facial recognition and cheerfully greet you at your front door. Some personal robots can carry on a somewhat meaningful conversation, though a bit stilted. Some of the mobile robots can bring a person food or drinks from another location where a human has placed the requested items on a tray to be delivered. Home robots seem to be skilled at many household tasks.

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Are Social Robots like Jibo and Paro Applicable for Seniors?

table doing its little dance moves and talking up a storm. Jibo’s AI may just end up being a good chatbot to entertain seniors as Dr. Breazeal is determined to give the robot a true personality.

Robot Interactive Conversation

The soon-to-be released Jibo (have you heard that The previously before?) is called a mentioned Alexa, robot as it has a Cortana, and Siri were movable head and Figure 11. Jibo's LCD screen shows not designed to be torso, and is more than a white ball. true conversationalists. designed as ‘warm’ True conversation is very and ‘part of the group’ to blend into complicated to synthesize with AI. everyday life and conversation. Shown A little over a year ago, Microsoft in Figure 11, Jibo is a social robot introduced a conversational speech that has been “coming to the market” AI chatbot product called ‘Tay.’ The forever. I have to hand it to the image in Figure 13 is just a creator, Dr. Cynthia Breazeal for not representation of the female just pushing a product out the door character as Tay is just AI software. before making it perfect, as so many Tay was trained to speak like a robot companies seem to do. millennial instead of a personal Yes, she’s irritated some early assistant like Cortana or Siri. It investors who felt it should have been could learn to talk just like the in their hands years ago, but as her people it was speaking with. The title says, she has a PhD in Electrical first users found it on Twitter, and Engineering and Computer Science then Kik and GroupMe, and it could from MIT and desires a product as interact with Microsoft’s Bing search close to perfect as it can be. Too engine. According to verge.com, many ‘buggy’ robots have been “The team used public data, along released to the public over the years. with input from improv comedians The videos of Jibo’s operation and AI experts alike.” certainly give one an impression that As many people are often it could be socially interactive for the tempted to do, early users of the elderly. I feel that this cute little robot software program quickly corrupted creation may end up being even more ‘her’ (Tay had a female voice) and she useful than the very expensive $5,000 became racist in her comments, along ‘animal therapy robot,’ Paro, modeled with other unacceptable remarks. after a baby harp seal. Paro (shown in According to a Microsoft spokesperson who said in a statement Figure 12) has been on the market for 10 years. I’m sure that the makers on GeekWire this past March, “It is as much a social and cultural experiment felt that an innocent-looking, soft, furry white baby seal was about as as it is technical. cute as anything to place in a senior’s Unfortunately, within the first 24 lap to pet. hours of coming online, we became My bets are on Jibo to outsell aware of a coordinated effort by Paro 10-to-1 or more for a sociallysome users to abuse Tay’s commenting skills to have Tay respond interactive robot for the elderly — despite Jibo just sitting on a nearby in inappropriate ways. As a result, we

Figure 12. Paro, the robot harp seal soothes a senior.

Figure 13. Microsoft's Tay was corrupted by devious users.

have taken Tay offline and are making adjustments.”

Physical Assistance Coupled with Social Interaction It is not just enough to have a care-giving robot be able to communicate with the elderly person; the robot should also be able to physically assist the person. Looking back at the earlier robots that I’ve mentioned, all were mobile and could be remotely controlled or programmed to move. All seemed to be somewhat anthropomorphic in shape and human-sized, except for the iComar. Only the Luna had arms, and those were simple tubes that could be manually positioned to hold something. That pretty much leaves all of these robots out for the task of SERVO 06.2017

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Figure 14. Genworth R70i aging suit.

Figure 15. Tandy Trower and Bill Gates during a robotics demonstration at Microsoft’s TechEd 2008 conference.

physically helping a person. How do we humans learn to interact with other humans? We seem to grow up in our societies by learning this complex task as the years pass. It is rarely taught at a basic level. It seems that advanced university-level classes are the only sources of learning the particulars of this critical task.

An Exoskeleton Teaches Researchers What it is Like to Age An article by Claire Maldarelli for popsci.com stated, “As Atticus Finch tells Scout in To Kill A Mockingbird, ‘You never really understand a person until you consider things from his point of view ... Until you climb inside of his skin and walk around in it.’ “ With the R70i Aging Suit, you nearly can. The Genworth R70i Aging Suit is a special exoskeleton suit that a younger person can put on to simulate what they might feel like at an older age. The suit’s inventor, Bran Ferren wondered what it would be like to be old. The stooped shuffle, the halting speech, the dimming senses. His 40 pound suit shown in Figure 14 can simulate many older ages, physical difficulties such as a failing hip joint, difficulties in reaching a tall shelf, blurred vision, and similar difficulties.

Tandy Trower of Hoaloha Robotics I’ve known Tandy Trower for a

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number of years and have visited his facility in South Seattle. Trower joined Microsoft in 1981 when there were less than 90 employees, and was head of the team that produced the first two Windows operating systems for Intel-based computers, popularly called PCs. I first heard of Trower when — as part of Bill Gates’ strategic staff — he was tapped by Gates in 2005 to form the Microsoft’s robotic initiative. Trower is shown with Gates in Figure 15 when Gates introduced him saying: “Tandy Trower, who runs our robotics group ... he actually founded it, evangelized it, and has a lot of passion for this.” This was at Microsoft TechEd 2008 in Orlando, FL. Trower developed the Microsoft Robotics Developer Studio that shipped in June 2006, and stayed with the Robotics Group until 2010 when he left to form Hoaloha Robotics, which is a Hawaiian word for compassionate friend. I have been keeping in touch with Trower as he is developing a very sophisticated robot to serve today’s seniors. I have seen several of his prototypes and they are amazing. Tandy is creating a human-sized robot to assist the elderly and has perfected some amazing navigation systems using LIDAR, vision systems, and typical sonar and light beam sensors to accurately move about one’s home. I have also given his most of my personal assistant robot research data as I feel that he is as

close as anybody in producing a truly workable robot for the homes of the elderly.

Help! I’ve Fallen, and I Can’t Get Up! We’ve all seen the long-running TV ad about the Life Alert medical emergency response system for senior safety. The elderly person is lying on the floor and speaks those memorable words into a pendant around her neck; she then hears a comforting response saying the emergency personnel are on their way to her home. Practically every comedian around the world quickly used these words in many contrived situations, such as the cat in Figure 16. Sure, we can all laugh, but the scenario is so true. I have seen several situations myself where my mother-in-law laid on the floor for hours until her husband arrived home to assist her off the floor and into a chair. She was not hurt, but easily could have been.

Personal Assistant Robot to Allow Seniors Independent Living It is for these specific scenarios that I would like to see a personal assistant robot developed to allow millions of seniors independence in

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Figure 16. A cat call for help.

their daily lives. A robot with two powerful verbally-controlled arms that are specially designed to safely handle fragile human beings needs to be developed much farther than my initial designs. The FDA Code of Federal Regulations, Part 890.5050 describing “Daily Activity Assist Devices” will be the big stepping stone that must be overcome. It can and will be I’m sure. The Japanese Robear shown in Figure 17 is a good start, but all the photos show the robot carrying a healthy young person who is alert. An elderly person who may be asleep or barely alert would slip down between the two arms if it were not for the red and white sling barely seen below the ‘patient.’ Carrying a person is not something that a human caregiver would do in a private home situation, but probably would be in a nursing home. Typically, a personal assistant robot would be used when the person desiring independence only needs assistance from a non-injury fall, or assistance to and from a chair, bed, or toilet. The other tasks for such a robot would be fetching items and delivering already prepared meals. Actuonix Motion Devices ........................53 All Electronics Corp. ...........................13, 17 EarthLCD ....................................................13 ExpressPCB ................................................46 Front Panel Express ...................................57 Hitec .............................................................2

The user of the robot should have basic manipulative Figure 17. Robear lifts a 'patient.' Note the two protruding feet to stabilize the robot. skills and minimal strength in their body. wanted to emphasize the difficulties I would suggest that a person that decades of robot designers have interested in a robot for an elder start had to and will have to overcome to with one of the many telepresence have a viable home assistant robot for robots like the ones shown in Figure the elderly. 18. Startups, universities, and even larger companies are looking to the future of elder care when 50% of the I started this article by describing group of those 85 and older will a series of robots that could be used require assistance in their daily as a personal assistant to allow a activities. I believe folks like Tandy senior continued independent living, Trower and other talented robot and then stated that none of them researchers will arrive at that perfect are really capable of the task. I just design solution soon. SV

Final Thoughts

Figure 18. Telepresence robots allow mobile remote contact with another distant person.

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THIS SIDE UP

Introducing the Balboa 32U4 balancing robot kit from Pololu.

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