[wattnotions] has been playing with matches, well the box they come in anyway. One day he was letting synapses fire unsupervised, and wondered if he could build a robot inside of a matchbox. His first prototype was a coin lithium battery and scrounged motors from those 3 US Dollar servos you can buy by the dozen. It scooted around just fine, but it drained the battery instantly and was a little boring.
Next, he etched a board. It had a little PIC micro, a connector for a mini LiPo, and an H bridge. It fired up just fine, and even though it drained the battery way too fast, at least it wasn’t brainless anymore. In our experience, robots tend to discard all the useful data they collect anyway, so being blind wasn’t too much of a problem.
Inspired and encouraged, with synapses gloriously undeterred, [wattnotions] set out to make a version 2. This time he ordered a board from OSHPark, made a 3D model in SketchUp, and proceeded to lock himself out from his own chip. Without a high voltage programmerhe was out of luck. The development was unfortunately put on hold.
It was fun to read along with [wattnotions] as he went on a small robot adventure. We hope he’ll complete a version 3 and have a swarm of the little fellows scooting around.
For a second I thought he was building these in the chassis of Matchbox cars but I see he’s using the boxes that matches come in.
There is plenty of I/O free so he could had a remote control. It can make car turn in wanted direction by differential PWM control of motors, as the motor with the highest PWM duty cycle will rotate faster than the one with lower PWM duty cycle.
He could also control the forward speed the same way.
navigation with an accelerometer (i.e. reverse out left, right or center after bumping into something) might be a fun thing to try on this…
Articles about tiny robot inside matchbox was on hackaday few years before:
http://hackaday.com/2011/09/07/matchbox-sized-line-following-robot/
http://hackaday.com/2011/12/05/update-tiny-line-follower-and-more/
I made a tiny line follower, but I didn’t craft my own PCBs.
I did have to hand-craft inductors though! :-)
https://hackaday.io/project/563-hand-wound-inductors-for-a-tiny-robot
He’s without an HV programmer… but it’s pretty trivial to make one yourself. PIC just needs a 12V source but signalling is still 5V is it not?
Nice project. The poor battery life is probably down to motor size and gearing. Those motors are too big for a vehicle this size! Also the friction from not having a third wheel is probably not ideal!
I’ve got a similar sized RC car which uses two of the ‘nano quadcopter’ sized motors. One for the drive terrain with a couple of small plastic gears (I bet you could use the ones in the servo) and one for the rack and pinion steering. The 90mah battery outlasts me getting bored.
The steering is interesting because it just uses a resistor to limiit the stall current of the motor. The steering is pretty ‘binary’.
I’ve also got a slighly larger car which has a tiny penny-sized servo with no pcb in it – it has a 6 wire connector so offloads the processing/driving to the IC on the car’s main PCB. I’d love to be able to get those cheap!
Gerrit, you have made my day. “with synapses gloriously undeterred” is one of the most brilliant phrases I’ve heard in a while. Much better than “Watch this; I’m gonna try something.”, “YOLO!”, or other prefixes to Darwin Award worthy events.
Thanks! Haha, I appreciate it :D