View Single Post
Old 2011.09.21, 11:46 AM   #6
I-Lap
Registered User
 
Join Date: Oct 2004
Location: NW Chicago Burbs
Posts: 104
Pin 4 of the PIC is the PPM output from the radio. This portion is standard RC stuff with a variable length pulse of 1 to 2 milliseconds (1.5ms = center) to determine control position.

This is the best place to interact as you can either generate the pulsetrain with your board when you want control, or pass the original signals when you don't.

I haven't spent much time with this yet, but I did a rough project a few weeks ago with a wifly module and an AVR, driving the car with the tilt sensors on an android phone. You can see it here: http://www.youtube.com/watch?v=Z2JbViUoFFc. The car is the slightly larger one on the track, a CP cup f1 conversion.

Basically, keep the line (pic pin 4) low, then blip a high pulse for 200us, then keep low for 1-2ms for the steering then blip high for 150us, then low 1-2ms for the throttle, followed by another 150us high blip, then low for 18ms and repeat.

At some point soon, I will do a simple interface to get the servo pulses from a cheap 2.4 rx and combine into a pulsetrain to upgrade some AM cars.
__________________
I-Lap Timing Systems
Precision Timing for Small Scale Motorsports
www.rclapcounter.com
I-Lap is offline   Reply With Quote