I have a 2 channel remote control system (Futaba brand) typically used for remote control cars with 2 servos. I want to connect it to a 3V dc motor so that I can make it go slow or fast for a rising card effect. My assistant will control the speed backstage. What do I need to accomplish this. Thanks in advance!

I would think you could use the rheostat (speed controller) in an inexpensive R/C car to control the car motor with a pulley or rubber tire (depending on what you want to accomplish) mounted on the motor shaft.

An electronic speed control (ESC) would do the job for you. An ESC gives you proportional control of your motor and also supplies regulated 5V to your RC system so you don't need two battery packs. (In the old days we used one battery pack powering the motor, and a separate battery pack powering the RC system.) ESCs are available at hobby shops and also stores catering to the robotics hobbyist. Make sure to get one that works with brushed motors, not a brushless motor.

Do you need proportional control in both directions? Many ESCs are single direction only, like for airplanes. Some come with a reverse function but might not offer the same degree of proportional control as the forward direction (e.g. single speed reverse). Finally, some ESCs offer full proportional control in both directions. Some of these are popular with the robotics crowd. Here's one that's small in size and would probably work well for you:

http://banebots.com/pc/ELECTRONICS/BB-0309

I haven't tried this particular ESC but I've ordered from this vendor before with good results. I've only heard good things about them.

This ESC would also work:

http://www.robotpower.com/products/scorpion_mini_info.html

It's currently discontinued but evidently you can still find these. Here's one vendor:

http://www.trossenrobotics.com/store/p/3......ini.aspx


In either case the ESC would need to run at a voltage higher than the voltage your particular motor is rated for, so I'd consider replacing your 3V motor with, say, a 6V one. If you're set on using that 3V motor, there are things you could do to prevent putting too much current through it and burning it out prematurely when running with 6V.

If you're handy with a soldering iron and a bit adventurous, you could also hack an inexpensive RC servo. But the ESC approach would likely be the easier path.

Good luck!

Ross Hironaka

Rhiro, is right that is what I used, mine is from a backyard flier airplane, all micro componets. Owln_1