This little guy exists as a courtesy. He makes his binary way to the nooks and crannies of the house in case someone there might need to measure a resistor or check battery voltage.
Like the my Dune BuggyBot, he’s made up from a pair of Tamiya dual DC motor and gearbox sets mounted to some Erector Set parts. He uses a pair of SRF05 ultrasonic range finders, mounted back to back. The robot has no front or back; if it encounters an obstacle it merely reverses everything about itself. What were the front sensors shut off and the opposite one turns on, the motors reverse, and it continues to explore its surroundings. Setting the left motor to run slightly slower than the right side motor makes sure that the MeterBot doesn’t just go back and forth in the same place all the time. He swings a slow arc no matter which way it is moving.
The meter it carries is a real multimeter. It’s a Sparkfun kit I picked up from NKC Electronics. After assembling it and deciding it was functional but not necessarily handy, I decided to make it into a robot. So I guess you could say that I hacked this meter into a robot, or you could say I built a robot and hacked it to carry a meter. Personally, I think the hacked meter sounds cooler, but suit yourself.
He uses an Arduino Duemilanove with an Ardumoto motor shield. It started out with an Adafruit Mshield, but since this bot ties the two motors on each side together, using a 4 motor shield seemed a waste. Plus that, it has no servos. So the 2 motor shield is all it needs and it works great. It does power the motors with the same 5v the Arduino uses, so I’m powering it with 9 volts from six AA batteries and I use a 5v regulator chip on a breakout board to make sure I don’t overamp the L293 chip on the shield or overdrive the 6v motors. I suppose I could have just come up with a 6v supply, but hey, this is what I had. There used to be a Sharp IR sensor on it, but I took it off as overkill. (The code stubs are still there in the sketch though).