[sanddrag]

I think a full or zero PWM signal is still a signal, not a constant voltage, nor would you ever average it out to a volatage. Pulses to the speed control need to be kept just that, pulses, in order for it to be a readable signal. But pulses to the motor can be equivalated (new word ) to a constant (average) voltage because that motor is going to turn no matter if it is getting a lot of higher voltage little bits every now and then or a lower voltatge constant flow. As long as the juice is being applied, the motor will turn. But the same cannot be said for the control module. It reads pulses, not constants, because it is digital, not mechanical.

If it really is just to flip out a car stereo screen or something, you may want to just use a little microcontroller like a Basic Stamp and a servo. If a servo gets the range of motion you need, I'd go for that. Nice and easy. You can have a switch directly input to the BS and then the BS directly gives a pulsing output to the servo. Easy and pretty cheap. But I do get the feeling that a servo is not quite what you are looking for. You want it to have a nice slow smooth action with quite a bit of degrees of rotation right? Is this going to be like the stereos with pop out screens that they put in all the Pimp My Ride cars?