[mowbot] Proportional Radio Control

Michael Davenport (michael.davenport nospam at wheatstoneenergy.com)
Wed, 16 Jun 1999 13:22:07 -0400

I have found an interesting little circuit for proportional radio control.
I am not very well equipped to test this circuit, so I was hoping that one
of you might have had some experience with it. It is found at

I have purchased most of the parts and I am building it on a proto board to
test it. Anyone have a circuit simulation software package that could test
the concept?

I am still needing the 0-100K potentiometers and the salesman at my local
electronics retailer said "yeah, you're gonna want to get pots with real
high resolution, that's gonna be expensive." Where can I get pots like
that? I'm still waiting on DigiKey to mail me a catalog since I have had
trouble searching their catalog on-line. I would like to use a joystick
type pot (or trigger preferably) for speed and direction control, and a
rotary (knob type) for steering - just like the setup on the pistol grip
transmitters used for R/C cars. Where could I buy parts for a pistol grip
transmitter? (The trigger and the knob potentiometers specifically) Anyone
know what the resolution is on those R/C transmitters pots?

The website in the link above, Harry's Homebrew Homepage, has some neat
circuits and ideas. If any of you try out any of his circuits (or have
already tried some) please let me know of your experience, good or bad.
He's got some neat projects there such as a bench power supply and a
wireless FM microphone.

I want to use an el-cheap-o transmitter / receiver from Radio Shack (AM 27
MHz), Harry's encoder / decoder circuits, and a PWM speed controller for the
drive motors (either a stock part for R/C cars from Tower Hobbies or a
custom built PWM higher voltage unit) The steering motors I haven't figured
out yet. I doubt a standard servo will have enough torque to steer a 100
lb. + machine on 10 or 12 inch knobby tires.

Could one use LED's in place of the diodes in the encoder / decoder
circuits? (I have a bunch of LED's on hand, but no diodes).

Thanks All!
Michael Davenport