I’ve been researching dc motor control for a sound-sculpture project which will involve a central motor activating various sound devices via switches, contact mics, etc.
I have settled on windshield wiper motors as they are powerful, versatile and readily available.
I already have a small collection of these motors, now I am trying to figure out the best way to control them.
I would like to run the motor on a variety of speed, from very slow (under 1 RPM) to faster (lets say 20 or 30 RPM), though the slower speed will be more important.
I have been looking at PWM controllers, but I am concerned about the amount of noise these seem to generate in the motor (I want this to run as quietly as possible).
I have come across high frequency PWM controller (ie: criticalvelocity.com/item.php?itemid=spdc11) which may do the trick, though I don’t have the proof yet.
The other option I am considering is using an H-bridge controller (ie: robotshop.com/world/parallax-hb-25-dc-motor-controller-2.html) though for this I think I would need a micro-controller, correct? (Potentiometer won’t cut it?) To be honest I’m not even sure what a micro-controller is!
For me the simpler the solution, the better.
I would appreciate any advice or product suggestions to enable this project to happen soon!
Thank you.
I decided to go with the Sabertooth Dual 12A 6V-24V Regenerative Motor Driver Sounds powerful enough, versatile, and quiet. Also Sabertooth’s approach seems very user friendly, particularly in their additional documentation (how to hook it up with a computer power supply, explaining the regenerating process, etc)…I look forward to receiving it.
Thanks.
It is an older motor, so perhaps there was some internal friction that built up while sitting unused.
I guess I didn’t catch the trouble quickly enough before frying the control unit…I will be exchanging the 12A dual for the 25A single. Hopefully it will give me more leeway for situations like this.
Hi again,
Since ordering the Sabertooth Dual 12a I have had some problems…After using it lightly, using an ATX power supply with battery as suggested in the users guide, I started getting Error warnings from the red LED on the board. I contacted Robotshop, who then graciously replaced my faulty board. For a while I had no problems with this one, using it to control a wiper type motor, totally silent, no problems. Just last night I tried hooking up a different motor to the main M1 terminals, a slightly larger wiper motor, connected to a simple gear system. Trying a larger motor shouldn’t be a problem according to the Sabertooth promo page:
“Overcurrent and thermal protection means you’ll never have to worry about killing the driver with accidental stalls or by hooking up too big a motor.”
After about 30 seconds the motor started smelling a bit, so I turned off the controller. Tried it again a little while later and got the same effect, then noticed the Sabertooth had gone silent, no LEDs, no power. I unplugged the motor, connected the smaller wiper motor I had been using and again, nothing, tried disconnecting and reconnecting my ATX and battery several times, nothing.
Overall I am dissapointed with this product, as my project requires reliability, and it seems this controller cannot deliver.
I can’t find an amperage rating for the motor, though I do know that wiper motors generally run at under 10 amps.
I had used the same motor with the Sabertooth before without a problem.
The motor was struggling before I turned off the power, though I’m not sure why as there wasn’t alot of load on it.
The promotional material for the controller had me convinced that I could try heavier motors without worry of frying the board.
First, take a look at this article: How to Make a Robot – Lesson 5: Choosing a Motor Controller
You need to know the motor’s nominal voltage and also the maximum continuous current. Once you have these, we suggest an analog DC motor controller (assuming of course the motors are DC, which they likely are). You need a good quality controller and a good quality potentiometer, and you’ll be fine.
The Sabertooth controllers are usually very reliable. They do have protection but it is possible to fry them with enough load. How many amps is the big motor rated at? Does it exceed 12A? Also, was there any stalling (i.e. locked shaft) of the motor due to high torque applied to it?
Would it be possible that the motor was old, blocked or not functioning properly. If the motor was blocked for extended periods of time or was fighting a lot of internal friction, it is possible that it consumed more current than usual.
The controller would forgive you if you accidentally connected a heavier motor during a short period of time. However, it cannot do anything against long periods of stress that go above its rating.