I proceeded to rip out all its electronics and battery contacts and cover etc, leaving just the underchasis and two motors. I then put my own little 900mAh lipo in the battery compartment along with a small motor driver board (two h-bridges), with all the wires running through the old contact holes. An STM32 dev board went on top and connects to a Sharp IR rangefinder and xbee radio.

All I had it do to start with was drive forwards, then when the ADC detected the voltage from the Sharp sensor went over the limit that indicated an obstacle was ahead, an interrupt fired which caused the car to reverse back and to the left slightly. This was enough to avoid most collisions so the car could pretty much drive about as it wanted. Later I added remote control from a computer over the xbee, with the same interrupt code for collisions. I was planning to put a GPS and some other sensors on the car, but shortly after making it I ordered all the parts for my upcoming quadcopter, which is going to take the limelight for now.

I decided I wanted something with a lot of interface peripherals, so broke out USART1, 2 and 3, I²C1 and 2 (also USART3) and SPI1 and 2. Additionally a USB plug is connected to the USB peripheral, and JTAG is available. The 6pin header for USART1 is compatible with the FTDI cables/breakouts which makes interfacing with an FTDI cable for programming (the bootloader listens on USART1) or with an xbee on one of SparkFun’s breakouts is very easy.

So far I’ve used one of these boards for Robot3 (an upcoming post) and plan to use the second to start prototypes with my quadcopter UAV. They’re pretty useful, uploading code to them is quick and easy with the bootloader, and having that many peripherals available and capable of running at pretty high speeds makes these boards handy to have around.

Eagle files and a PNG here.