Hi Robert, I think I worded this confusingly. When I said "drives the motor directly", I meant "provide the actual motor ON time". Of course, a motor whose PWM "on" time only varied between 5 and 10% wouldn't have much torque. The prosthetic limb project sounds really interesting! Sean On 5/6/07, Robert Rolf wrote: > > The signal received by the receiver is PPM encoded, but the receiver > > converts this into PWM for each servo. Note that unlike regular PWM, > > this is not used to directly drive a motor but rather to send a > > command. > > Actually, in most early (non digital) R/C setups the pulse DOES drive > the motors directly. The leading edge triggers a monostable whose period > is set by the current servo position. An exclusive-or of the incoming and position > pulses go to an H bridge, whose direction is set by which edge fell first. > The result is pulses to the motor (at the frame rate) that are portional > to the position error. > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist