Rebounder is a quick little platform that had been adapted from a Tyco Super Rebound RC car. The original radio receiver electronics were removed, and an IsoPod driving 2 5A h-bridges were installed. The original battery was used, as were it's contacts and the original power switch. Rebounder in basic form takes a momentary switch sensor as input, to begin the programmed sequence.
Navigates a preprogrammed sequence of timed moves
Actuators / output devices: 4 wheels geared to 2 motors (1 for each side)
Control method: autonomous
CPU: IsoPod (Freescale DSP56F805)
Operating system: IsoMax (Forth with state machine structure)
Power source: 7.2 NiMh Tyco Flexpack
Programming language: IsoMax (Forth)
Sensors / input devices: has had SHarp sensors and CMP03 compass, currently single momentary switch
Nope, normal speed That’s just how quick the little car was. The car might be a little faster than it was originally, as the h-bridges are FET based, rather than BJTs, so it could be getting a little extra voltage off the stock battery pack.
These are made at New Micros, and have a header at one end for logic power, an A input and a B input like the L293D you have, and also an added “not A” pin (to be jumpered to the B pin, for using a single PWM for locked antiphase drive) and an error output. There is also a header that has one input, logic power and ground like servo wires in the middle. The end has screw terminals for motor power and ground and the 2 outputs to hook up the motor. There are a number of LEDs on the board to indicate power, inputs, and outputs and they look pretty cool on a robot in the dark. And it’s all wrapped up in a big heatsink normally, except I switched it out for a smaller set on Rebounder. The main driver on the h-bridge is an Infineon TLE5206 (-2 or -2S I think). It’s got a lot of cool protections and features on it.
One note, there is no enable pin on these, so your processor may need power on operation with the PWM either high or low, or at a 50% PWM duty cycle if using locked antiphase drive to prevent movement.
It initially was built for an indoor competition, for 1 event called “Quick Trip”. That was just a 16 foot out and back contest. And the robot was almost too fast for it, but did good enough. Outdoor robot competitions were proposed, and so the compass was added to Rebounder (ok, not so original name), but something was weird with my code (from the night before the competition) and so it did not function well.
There is some problems in getting it to move at a lower PWM duty cycle, a sort of narrow band of PWM rates it will function at. If the on time is much below 85% duty, the robot can’t move. I need to play with PWM frequencies (some motors function better at other PWM rates, using 20 kHz). I had planned on a couple Sharp sensors, but the robot probably moves 2-3" by the time a new reading comes in, plus the inertia requires a longer distance sensor. Probably some Maxbotic sonars, and some method of wheel encoders might be added, after playing with the PWM duty/frequency some. For now, it is just going to have fun doing zippy little preprogrammed dances. You should see the grins on little kids faces when they push the button and make it go. (Some at public robot events here)
Cool thing! A shame you didn’t program in the flipping things it could do I’m also working on a rework of this car, which can be found here: http://home.deds.nl/~cmon/firo.htm
The IsoPod runs $99, has a lot of hardware features that you’d have to combine several other devices to match. It’s somewhat overkill for this robot now, but maybe in time I’ll use a few more features here. H-bridges are $30 each, a pretty fair price when compared to others. Think the other $15 was for the battery or the car or something. This is about an average robot as far as expense. Think Lego Mindstorms, about $200 for a set. Or the Parallax BOEbot, about $160 I think.
Microcontroller boards I know of can run as cheap as $15, on up to $200+ depending on what’s there.This can be a substantial cost, but can save you time and give yourself room to grow, depending on what direction you go. I have robots that cost about $50, on up to one that is pushing $400 (and still not working).
Other peoples hobbies :
bowling league, $3 shoe rental $5 lane/game, about $13 a weekend night over 2 months = $104 plus “refreshments”
video games, $150 to $400 plus $20 to $60 per game? Wiiiiii : )
golf, how much are clubs? $200? plus round of 18 - $20 - $200 (La Costa)
model airplanes or cars, $150 for a radio, $80 - $200 for a car/plane
computers, $200 for a near adequate system to $5000 for something scary that dims the lights when it turns on.
It’s kinds a like, pick how far you want to go. You can get by cheap, but it isn’t always what works best.
I’m lovin’ the rationale for not doing other projects…!
Could you put a price on soccer? (Break down for both playing AND watching.) I hate soccer, but you might be able to help me rationalise the irritation.
My other hobby is model railroading. My standard answer when people ask why I paid $250 for a new locomotive is, "Well its a lot cheaper than a $20,000 fishing boat that I can use maybe 10 times per year."
I’m also working on a rework of this car, which can be found here: