VJ DeLeon's Micro-robotics & Remotes
Projects:
MGR-K401 Robotic Dog
In November 2004 I ordered this kit from E-Clec-Tech and I've been working on it ever since. It only took a few hours to put together, and another week to sort out some minor problems like the battery voltage being too high and being turned off by the safety circuit. Anyway, I've been a bit overwhelmed by some of the more challenging stuff I've had to figure out to make it stand up and walk, but I have made some progress with the help of a friend from work. The motors are not really servos, they are more like digital actuators and are called AIMotors because they have all these cool features like position and current feedback. This particular model is the second gen of the Ai series, the AI701 specially designed for robotics by Korean manufacturer MegaRobotics. The dog kit used fourteen of these AI701 modules for the dog's body and head. The more powerful AI1001 is also available. More on this when I get some free time.
You can find the kit at Tribotix and also E-Clec-Tech for a bit less.
 
Notice the ATMEL ATmega128 board sitting on top. Quite a bit more advanced than what I'm used to.
 
I promise I will be posting more on this soon. In the meantime here are some specs for the AIMotor taken from the MegaRobotics site:
AI-701 Specifications:
 |
Maximum Torque(at 9.5V) |
7Kg·cm |
Maximum Speed(at 9.5V) |
82rpm |
Gear ratio |
1/173 |
Gear material |
Plastic |
Bearing |
None |
Weight |
40g |
Size |
51.6 x 34.3 x 37.1mm |
Mechanical connection points |
2 |
Electrical connection points |
2 |
Polarised connector |
Yes |
Lock type connector |
Yes |
Control signal |
Serial Data Packets |
Baud rate |
2400~460800bps |
Controllable range |
0°~ 332° |
Inverse voltage protection |
Yes |
Resolution selection function |
2 levels (1.30° & 0.65°) |
Overcurrent protection |
Yes |
360degree rotation function |
Yes |
Position feedback function |
Yes |
Current feedback function |
Yes |
Power down mode |
Yes |
Speed of the position control
mode |
5 levels |
Speed of the Rotation
mode |
16 levels |
Parameter setting function |
Yes |
| Auto gain tuning with voltage detection |
Yes |
| Bound Setting Function |
Yes |
Synchronised Position
Control Function |
Yes |
|
My friend Nate has written a cool servo controller app in C# for Windows and has been helping me use it to make the dog move. This is a shot of his Behavior Studio with a motion graph window on the right showing some of the stuff i'm trying to wrap my brain around. it's a lot harder than it looks. Here's a video of some progress. More to come soon.
Parallax BOE Bot
So I was at Radio Shack [...surprise...] and saw that they were selling this kit and thought it would be fun so I got one. A bit of history on the Boe bot, it has an uncontested reputation for being the de-facto robotics starter kit and has sold incredibly well. BOE stands for Board of Education, which is what they are calling the main board the microcontroller sits on. It has several inputs and a nice little breadboard so you can make test circuits without soldering. There are countless Boe bot modifications, hundreds of websites, books, even day camps for kids. Anyway, this is an inexpensive, fun, and super easy kit to build and play around with. If you want to kill a few hours or teach someone about robotics then I highly recommend this kit. There's no soldering involved, and it comes with all kinds of sensors, several programs on CD, and tons more available online. Like the Mini Sumo's, this kit is powered by a BASIC Stamp2 microcontroller that you program via a serial port to your PC. The kit is available at your local Radio Shack for under $150 here, or directly from Parallax.
What does it do? Well, in less than one hour I've gotten mine to follow a beam of light, and chase a flashlight around the room. I've taught it to follow one of my Sumo bots around and not hit it, or anything else. I've also tested my Sumo code on it, which is fun as long as I don't let it slam into my foot or anything else.
 
As mentioned in earlier posts, you might need a serial (DB9) to USB adapter if you don't have a serial port. The adapter I've found best is the FTDI US232B USB-Serial Adapter.
Kelo and Yama-Chan
 
These are two nearly identical regulation sized Mini-Sumo Class robots, each fitting perfectly in a 10X10cm box and weighted down to exactly 500 grams for competition. The design is based on the Northwest Robot Mini-Sumo Tournament Rules. These are both powered by a BASIC Stamp 2 board that I program via a serial port to my PC or laptop. The parts are from the Parallax Mini-Sumo kit available here.
Both of these guys will locate and try to push/shove/knock each other out of a flat, circular ring (called the Dohyo) all the while detecting the edge of the ring and not falling out itself. Tricky behavior for a robot to do if you think about it. 2 infrared sensors on top locate movement from another bot, while 2 more facing the ground make sure it doesn't touch the white line running along the edge of the ring. The movement is powered by 2 continuous rotation Futaba servos.
Although the kit comes with a serial cable to connect to your PC, the USB-Serial adapter I've found to link this particular microcontroller to my laptop (which doesn't have a serial port) is the FTDI US232B USB-Serial Adapter. From what other folks have told me this is the most reliable adapter with solid drivers for Win9X, ME, 2000 and XP.
Update: September 27, 2004
I thought you’d all be happy to know the results of my two Parallax mini sumo’s from the Beginner Class competitions at the 2004 Seattle Robothon:
“Kelo” managed to win 6 rounds but was finally ousted twice by Kristina Miles’ powerful “Oops!”
“Yama-chan” battled all the way to the final rounds and to my great surprise and satisfaction placed third! yielding to Prometheus Jr. for 2nd, and Oops!, for the 1st place win.
They both did exceptionally well for my first competition. Thanks to the Microsoft Robuild Group, and everyone who came by to watch.
On a side note, the Advanced Mini Class was a whole other animal. There were some really well designed machines competing in these events. The victory went to Solarbotics’ Grant McKee for Ender’s Wraith. Portland Robotics club’s SLICK was the 2nd place winner, and was my personal favorite. Quite an impressive little machine with an immense amount of traction and power.
Full results of all the Robothon 2004 events are here.
Fredfly
Fredfly doesn't really fly, but he's one of the fastest BEAM bots I've ever built. He is very similar to Fred Jr, the only difference being the two parallel mounted solar cells. These are Panasonic 2422's, and are some of the smallest you can get, measuring 24X22mm, and pumping out 4.15 volts 7mA each. I epoxied these together with a slight V tilt to catch the light better, and then angled them a little bit forward in the final position. I had to use a little square of foam packing to wedge between the body and the cells to make it more stable. Here's a good view of the guts.
This was a really clean solder job, and the solar engine fires quickly. He's very active and only needs partial sunlight or a strong indoor light to move around. The mounts and the connections are very sturdy, and I think he's going to last a long time. If I were to let this little guy loose outside he'd hop his way out of the neighborhood he's that fast. I'll post a movie of him eventually.
 
He's almost exactly the same size as Fred Jr, only 5.7 X 3.4 X 2.4cm and weighs 18 grams (0.6 oz). You can get a good look at the way I mounted the support onto the motor mounts. I straightened and cut a small paperclip and then bent the ends into squares that fit into the back of each mount, then bent the mount's clips over tightly with pliers. Then I heated each mount up with a small torch and soldered away. It's an extremely sturdy method.
 
Mantid
Mantid uses a 1381J solar engine I freeformed in one night. The sensors are standard photosensors and the solar cell is a Sanyo AM-5711. He weighs in at 18 grams (.6 oz) and is fairly active in bright sunlight.
Here you can get a good view of the guts. I used parts and the circuit design from PagerMotors.com and you can scroll down past my pictures to check out the schematic. The hardest part to find is the 1381J CMOS voltage regulator instead of FLEDs. The 1381 looks a lot like a transistor but it's not, it's more like a diode, or a valve I guess. Radio Shack doesn't carry them so you have to order them from Solarbotics, or Andy Pang who sells them for $.68 each.
I tried something different for the motor mount. This time I heated the individual mounts up with a small torch and then soldered them together with some heavy solder. Then I soldered the whole thing directly to the capacitor's negative lead.
 
He was popping a little too far so I added dual skids in the front. They kinda make him look like a Praying Mantis, which is how he got his name.
 
Click the image for the full schematic courtesy of PagerMotors.com
Fred Jr.
Update: Feb 21, 2004: Fred Jr. is one of my latest series of smaller versions of the classic Fred Photopopper using a FLED solar engine. This little guy uses a similar circuit design as the original Fred, except this time I tried to keep it under 6cm and I barely made it. The overall dimensions are 5.9 X 3.4 X 2.4cm and weighs 16 grams (0.5 oz). He's really active and finds the bright spots very easily. It's one of the quickest solar bugs I've made to date, beating out Fred Senior, even with his twin Sanyo panels.
 
It's powered by a Panasonic 2433 Sunceram solar panel that pumps 3.45 volts and 17.5mA. The panel is 24mm X 33mm X 0.7mm thick, and I highly recommend it. You can get this as well as the smaller Panasonic 2422 over at Andy Pang's Solar Bugs Kits and Parts.
 
I spent a little more time on Fred Jr.'s aesthetics as you can tell. I used a lot of blue heatshrink tubing on the feet, and matched it with the LED blinders. I also covered the .22uf caps. The lightweight aluminum tubing was fashioned into a mount in the rear for the solar cell. I didn't trim the dorsal support piece over the main cap because I thought it looked cool.
I added a small front skid to prevent him from popping too far, which he likes to do in bright sunlight. Another bot I am working on is getting a pair of front skids that look like legs. I'll be posting shots of it and the other solar bugs soon.
Nanner
 
This little guy is going to be in the "work in progress" status for a while. It will take several months until I figure out where to take the design. My first goal was to fabricate a class 1 bot chassis (under 4cm), but ended up with smaller parts and got it down to 2.5cm which would make this the smallest scale I've ever constructed, and from scratch nonetheless.
 
So far the chassis measures 2.5cm all around and weighs only 3.5 grams (0.1oz), well within the Class 1 spec. The lack of weight is partly due to the extra-lightweight properties of the particular hobby aluminum I used for the main pillar and side supports. As you can see I haven't soldered the center pillar in place yet- more on that later. The main ring was bashed from an old Hitachi VCR's helical recording head and is extremely lightweight. I find these VCR parts to be very useful so keep an eye out for them in the wild. Crack them open and look for the big, shiny chrome cylinder and unscrew it into its components.
 
The two motors I selected crank out 23,500 RPM and measure 12mm. These are hi-performance ZipZaps upgrade motors you can buy at any Radio Shack (#60-7521) just make sure you buy two of them so you get paired motors. I mounted them at a 20 degree camber from the support posts and gave them a forward angle to keep the chassis somewhat level when it will finally run. Right now it rests on the two motor shafts and the center ring rather neatly but any momentum will send it flying backwards on the main ring, I'll probably end up adding a rear skid to counter that. The two rear screws on the side supports act as adjusters for the each of the motor beams, so if I need to spread out the bot's stance I can do so by turning the screws slightly.
 
The unsoldered center pillar is being used as a placeholder at the moment. It will be removed and the center ring will house a simple photovoric sensor, or perhaps something more complex if I can squeeze it in. That will be the fun part of this project. I'll probably end up using a small rechargeable NiCd for power. More pics soon.
Fred
Update: Feb 8, 2004: Fred is finally finished and is popping along very nicely thanks to two Sanyo AM-5711 glass solar cells with an output of 7V at 21.1mA in full sunlight. The cells add an extra weight of 9.2 grams which is pretty heavy considering some of the alternatives out there. Still these are great and if you want to get some for your bots they're over at PagerMotors.com and are only $2.25 each and come with soldered leads. Fred's final dimensions are 7.7 X 5.8 X 3.5cm and weighs in at 30 grams (1.1 oz).
 
I had to increase the size of the shrink-wrap tubing that I placed over top of the FLED's to prevent the solar engine from locking up. It actually makes him look more insect-like now as well. I added the stripes on the capacitor and motors to make it a little more aesthetically pleasing and true to BEAM standards. After all, that's what the "A" stands for in BEAM :)
Fred, minus his solar cells, showing off his new motor mounts and 7mm Namiki's in place. I used a paperclip for the base, and wrapped a small bit of wire around the "arms" and over the top of the capacitor to secure it in place. It looks great and is fairly easy. Check out Ray Diaz' motor mount tutorial and see what I mean.
Fred is another work in progress. I'm using a basic BEAM Solar photovore/photopopper design so this little guy will never have batteries- but should run forever as long as he can find sunlight. The flashing LED solar engine is the only part I've finished so far. I've built a few solar engines but this one is turning out to be the cleanest. This is the tutorial I used from Ray Diaz although I positioned the transistors a little differently. I've also found another great tutorial in Macromedia Flash at Robomaniac's site or Google "FREEFORM FLED SE".
I am using standard parts- 33 and 3.3k resistors, 3904's and 3906's, and .22uf tantalum capacitors. The large capacitor is a 3,300uf with the plastic removed. I'll post more shots soon.
 
Schematic for the FLED SE courtesy of Ben Hitchcock & Ray Diaz- click for full size.
For a fully illustrated and in-depth tutorial on how to build your own Fred check out Ray's BEAM Tutorials and Stuff.
Symba
Update: Jan 29, 2004: I replaced the hobby aluminum outer ring with lighter and thinner coat hanger wire while the inner ring has been dropped altogether. I used a simpler wire triangle in its place. The solar cell is a Sanyo AM-5711 glass solar cell from PagerMotors.com. I mounted it on a small piece of foam for shock protection.
 
Symba in December of 2003 with the old hobby aluminum rings, which I need to replace.
Symba is a solar-powered BEAM Symet that I have been working on for months based on a design from Mark Tilden's BEAM Robotics research at Los Alamos. It's almost finished, and I'm really pleased with how it's turning out so far. I'll be posting an AVI of it scooting around my desk soon.
 
It's using a simple FLED Solar Engine I free-formed manually without a board, along with 3 3,300uf caps so hopefully it will run under my desk lamp. The rings were formed from hobby aluminum, but brass tubing also works well. The motor is from an old CD Rom drive, and the fancy inside mount is the helical recording head from an old VCR. Dimensions so far are 7 X 3cm & 49 grams (1.7oz).
Beetley
Beetley is a classic autonomous beetle bot based on the Beetle robot v.3 tutorial of Jérôme Demers. It's an extremely simple little bot that you can finish in one evening with your kids, and use to drive your dog or cat insane.
Nothing too spectacular, no chips, caps or transistors, just a lot of soldering. Beetley runs on one of the most basic sensor systems that uses 2 SPDT switches (Radio Shack 275-016) extended with paper clips that act as whiskers. When he hits an obstacle with either switch, the polarity is switched on the opposing motor making him back up and turn simultaneously. Interesting to see him scoot around the room, especially if you add a small trimpot and some LED's. My version is a few centimeters smaller, running on 2 AAA batteries instead of AA's to power the twin 1.5 Volt Mabuchi motors (RS 275-016). I mounted the pot in the back, and added a small wheel bashed from a cassette recorder. It weighs in at 83 grams (2.9oz). Dimensions are 8.5 (12.3 with whiskers) X 9 X 3.2cm. I've made two of these guys but this is the only one that survived.
 
Micro-Cambot
Cambot is a Class 2 micro-remote running on a frequency of 27Mhz. It weighs in at 46 grams (1.6oz), and it sports a remotely transmitted, fixed Sony CCD color camera bashed from from an 8MM handicam.
The most notable features of Cambot are it's mini camera that transmits a (pretty decent) color picture remotely via transmitter to a nearby television tuned to it's frequency, and of course its size- a mere 7.5 X 7.1 X 7.0cm not including the antenna which is a small and lightweight 10cm from a Motorola Startac, that adds 3cm to the overall height!
Update: Jan 20, 2004: Cambot gets a new matte-black paint job. Also removed the huge Quickcam lens cover to reduce the weight.
 
Cambot's path is illuminated by 2 forward 26,000 ultra-bright white LED's and two side-mounted mini-LED's. The video transmitter uses compact DSP at 2.4Ghz with a range of about 250 meters (750 FT). The receiver is connected to a Memorex Color Pocketvision29 portable mini-television with video input that operates on 4 AAA batteries.
The upgraded Cambot is now at 25,000RPM with a gear ratio of 12:1, and a slightly longer life 120mah NI-MH battery.
 
The base of Cambot is constructed from a modified Radio Shack Zip-Zap micro RC racer (Stock # 600-7034) with rack and pinion steering and trim adjustment. It has a 100mah NI-MH battery. The stock motor cranks out 21,500 RPM, and the standard gear ratio is 12:1. The transmitter is the stock Radio Shack Zip Zaps 27Mhz box with forward/reverse trigger-style controller, steering wheel pot, switchable frequencies, steering trim adjustment, and recharger.
 
Update: Jan 3, 2004: Cambot no longer a remote? Someday... I've decided that he will eventually be converted to an autonomous rover if I can ever figure out the rest of the steps I need to make the transformation. I'm planning on doing a simpler take on Glen Hathaway's Tankbot robot based off of parts from the Tamiya Bulldozer kit. Cambot is much smaller so a lot of the parts will have to be replaced or made with alternates. I'll need A Sharp GP2D02 IR sensor which I am having trouble locating. Then I'll need to get my hands on some IR code and modify it appropriately the same way he did, which might be a problem since I'm not a programmer. I'll probably switch camera's before I do anything else. Thinking of the new X10 XCam2 wireless camera.
 
Update: Dec 24, 2003: Fabricated a miniature "roll bar" around the camera board and the cabling. It looks a little silly but functionality is key here. I couldn't bear damaging the CCD or the board.
Update: Dec 22, 2003: Bashed and added a small lens from a Connectix Quickcam to the tip of Cambot's Sony CCD. Those things are hard to open unless you know the trick. Needed to break out the Krazy glue to affix the lens armature as always, but it worked nicely and didn't gum up the lenses.
Update: Nov 29, 2003: Purchased a new motor and gearing from Radio Shack, and replaced the stock ones in the original Cambot.
Check out Dave Anderson’s Remote Piloted Vehicle. Although it is a much larger Class 4, It was my inspiration for making Cambot.
Check out the
Mpeg movie here.
And there's Alex's RC controlled ARobot with Video which is very cool indeed.
For a full listing of other Class 2's check out http://www.andrew.cmu.edu/~rjg/webrobots/small_robots_class2.html.
For a comprehensive explanation of the different classes, check out Bob Grabowski of CMU's Survey at http://www.andrew.cmu.edu/~rjg/webrobots/small_robot_survey.html
Quickbot
Update: Dec 26,2003 I replaced Quickbot's motor and battery with high performance ones I purchased on Ebay. Quickbot went from a stock 25,000RPM motor with a gear ratio of 12:1 to a BLAZING 45,000RPM with a gear ratio of 10:1, and 100mah to a 200mah battery.
Quickbot is my first Class 2 micro-remote so it's basically just a stripped down remote that doesn't have any specific purpose yet. I am looking into adding either bumper or IR sensors, and a basic Sumo-bot IC kit but I find myself working on Cambot more. Quickbot is currently running on a 29Mhz crystal. The base is built from a modified Radio Shack Zip-Zap micro RC racer (Stock # 600-7030) and has an upgraded motor that clocks in at 25,000RPM with a gear ratio of 8.25:1 and a 200mah NI-MH battery. Quickbot weighs only 25 grams, approx 1/8 of an ounce!
I have added a small platform which I am going to eventually use for something other than the additional resistors and the antenna.
The most notable features of Quickbot are it's speed- 5.4 feet per second, which is blazingly fast for a bot this size, which is it's other most notable aspect. Quickbot measures only 6.8 X 3.2 X 2.9cm. The antenna is small and compact and only adds 2.2cm to the overall height.
 
Using Radio Shack Zip-Zaps as platforms
Radio Shack’s Zip-Zaps micro RC racers measure 7.8 cm, approximately the size of a die-cast Matchbox or HotWheels car, and are remote controlled and available in two frequencies, 27 Mhz and 49 Mhz. Stripped of their plastic shells and decorative wheels, and upgraded with better batteries and higher performance motors, they make ideal bases for micro-robotics amateurs looking to experiment with Class 2 robotics and using inexpensive materials as a base.
The stock Zip Zap RC Racers have internal Nickel Metal-Hydride rechargeable batteries, which are charged on the top of the compact remote transmitter. The 100Mah Nimh battery, which generally provides a couple minutes' runtime on a 45-second charge on the controller. You can get a bit longer runtime by double-charging; charge, then remove for 10 seconds and charge again.
I have replaced the 100 with a 120Mah battery and have gained several minutes of runtime without having to double-charge. Zip-Zaps range in price from $19.99 to $29.99 for the Special Edition models. Motor kits and performance gears are also sold for about the same price. This is a link to the #60-7521 upgrade kit.
Modded Tamiya Quadruped
My slightly modded Tamiya Quadruped. A slower-geared aluminum version is in progress.
Shots of my other robots coming shortly...
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