$10 Robot Platform - Part 2

Previously I posted that I had picked up a Thunder Tumbler from CVS for $10.  This past weekend I started working on making it into a robot.  Here it is with the body off and the circuit board pulled out.  The coiled spring is the antenna.  I'm not going to use the existing circuit at all but I saved it because it might be useful for something else in the future. I removed the front wheels because I plan to use it vertically.  The front wheels and/or the wheelie wheel are easily removed with just a few screws, which makes it very easy to customize to whatever configuration you want.  I also soldered some extensions onto the existing wires to make them easier to work with.

I don't have a fancy laser cutter or 3d printer so I had to find a cheap and easy way to mount and arduino, sensors, etc.  I bought a 10 pack of aluminum flashing shingles for a few dollars from Home Depot and used a pair of tin snips to cut one to size.  It worked very well.

I used a spring loaded center punch to dent the spots where I needed to drill holes.  This keeps the drill bit from slipping away and helps you to drill precise holes with a handheld drill.

Here is the bracket I made attached to the base.  I already had the standoffs, I've been hoarding the leftover hardware from computer cases for decades, but you can pick them up from amazon for pretty cheap.

And here it is with the arduino mounted.  One of the mounting holes in the arduino is too close the surrounding components to fit a screw into.  For now I just glued a cardboard washer to the standoff to keep it from shorting anything.  I may remove the standoff completely, or look into some nylon standoffs so there is no risk of shorting anything.

So far I'm pretty happy with it.  For $10 you get a base, wheels, two motors, and a battery holder.  Not to mention the wireless transmitter and receiver which are also very hackable. The base can easily be set up for a three wheeled or four wheeled robot and there is plenty of room for mounting other stuff.  I think I may even stop by CVS and buy a few more to have around for future projects.

$10 Robot Platform

I was at a CVS drugstore yesterday and I noticed a radio controlled car for only $10.  I'm currently waiting for delivery of a battery holder, two motors, two wheels, a caster, and some motor mounts from sparkfun, and needless to say, they cost more than $10 combined.  So I figured I'd give it a shot and buy one. The car is a Thunder Tumbler and it has terrible reviews on Amazon which is unsurprising.  As an RC car it is pretty awful.  The joysticks aren't analog so the motors are on full speed or off.  It's nearly impossible to steer and it pretty much always does wheelies and spins out.  I suppose that is the "tumbler" part of the name but the cheap plastic parts don't hold up well to the abuse.

None of that really matters to me though because I plan to strip it down and just use the motors and base at much slower speeds.  It even has a nice little removable battery tray.  I don't have any plans for the remote control or the existing motor control circuit but I will keep them around, they seem to be built with an RX-2B/TX-2B pair of chips and it could be fun/useful for some future project needing a simple wireless controller.  I'm just going to remove the existing electronics and control the motors with an adafruit motor shield.

After a little googling this morning, I find that I'm not the first person to have this idea.  You can see working examples here and here although I think I will try to use mine vertically, standing up on the wheelie wheel more like R2-D2.

Robocalypse

I've vaguely known about Arduino for a long time now but, to me, it's been almost just background noise on the internet.  I've just never really given it any attention until recently.  People invariably compare the Raspberry Pi to the Arduino and there is lots of talk about using the GPIO header for many Arduino-like tasks.  Eventually the constant Arduino noise penetrated my thick skull and I started to look into it and all I can say is it's amazing.  Things have progressed so far since I dropped out from studied electrical engineering at Michigan Tech.  I've forgotten most of what little I managed to learn in my first pass at college, but it hardly matters.  Arduino makes it easy and all the heavy lifting has already been done by people that actually got up and went to their classes. Even as recently as ten years ago I had a friend (okay not that recent but time flies when you get old) that claimed he wanted to build a robot and, at the time, it seemed pretty unlikely to me that he could pull it off (no offense Russ) but now it's crazy easy and cheap.  There is even a contest underway to build a robot for under $10.

Anyway, the point is, this Raspberry Pi of mine is likely to combine with an Arduino and I do my part to bring on the inevitable robocalypse.