Put your R/C car under computer control

Step 9 Hook it up to your computer

Plug your computer's serial cable into the board you just made. Give the board 9V and ground, and run the program radio that's listed below (remove the .run extension--again, instructables with that no-extensionless-uploads thing)
It's compiled for a linux machine. This code will only work on linux machines, I think. The source is in radio.c, also listed below.
The code I wrote uses the numpad to control the car. Be sure that num lock is on. Also, ESC closes the program.

If you want to write your own code, either because you have a PC/mac or just feel sexy, the details are:
the chip talks 4800 baud 8N1 serial.
the program is very simple--it will just spit out whatever number you send it on portB. If you send it '1', it will turn on button 1. '2' will turn on button 2. '4' will turn on button 3, etc.
email me at [e-mail] if you have questions