The 3pi robot is complete mobile platform designed to excel in line-following and maze-solving competitions. The 3pi has user accessible I/O lines that can be connected to different sensors to expand its behavior beyond line-following and maze-solving. This project shows one possible configuration where a two-channel radio-control (RC) receiver connected to the 3pi enables manual operation of the platform with minimal soldering. Many other sensors could be used to expand the 3pi, including distance sensors to make a wall-following robot.
By connecting an RC receiver and running the program detailed in Section 4, you can turn your 3pi into a radio-controlled vehicle that can drive at speeds in excess of 1 m/s and turn on a dime. A signal mixing algorithm makes two-channel control easy and intuitive, and the 3pi turns off its motors if it goes out of range, starts receiving bad signals, or if the transmitter is turned off. Here is a video of the RC 3pi in action: