first post here. I am a mechanical engineering student, but know little about electrical engineering or electronics. I am doing a project that requires me to (affordably) control the speed of a 12V DC motor. Here is the motor.

My issue is that I am unsure of what components I need to provide power to the motor and control its speed. I would like to use a wall outlet as the power supply and an Arduino to control the speed. I'd like to figure some of this out on my own, but I just need a little guidance as I walk through this project so I don't purchase the wrong components.

  1. Can someone first give me an overview of the components required (especially for power supply)? I believe I will get an Arduino Uno. I also think that I need an Adafruit Motor Shield. Then I'll need something to supply power to the motor from the wall. And something to supply power to the Arduino from the wall (or should I use a battery?). I'm pretty lost as far as the power supply. Transformers, transistors.. all of this is currently over my head.

I'm going to post updates to my progress and ask more questions as things are answered and I figure stuff out. If there are any guides that people can point to, that would be awesome as well.

  • \$\begingroup\$ Do you have the motor yet? If so, it would be helpful to measure its DC resistance (rotate the spindle a few times and pick the lowest value). Add that info to the question. If not, I'd recommend finding another motor with proper specifications... \$\endgroup\$
    – user16324
    Commented Nov 2, 2015 at 13:07

1 Answer 1


So I'll throw a some quick info at you,

  1. That motor looks to be quite big, it does not give a current spec but I would expect it to draw upwards to 10A when under load. That means any motor control shield or board you buy needs to be able to handle at least the maximum current (Which i am guessing is around 10 Amps).

  2. For a motor that large, it may be difficult to find a cheep power supply for it. If money is not a problem then I'm sure you can find a 12V supply on eBay that will work.

  3. To control the speed of a motor, you need what is called an H bridge or half an H bridge if you only want to go one direction. Ebay again will have a ton of H bridge circuits that you should be able to attach to a PWM (analog out) port on the Arduino.

I would recommend you get some current measurements on the motor you want to use before trying to build a driver system for it...

  • \$\begingroup\$ Back in undergrad I ran a pair of relatively beefy 12V motors (200 mA no-load, 5A stall) off an ATX power supply ripped out of an old PC. Worked fine, and they're easy to salvage. \$\endgroup\$ Commented Nov 2, 2015 at 4:43
  • \$\begingroup\$ The motor specs I saw (scroll way down the page) give a no-load current of 0.41 Amp, and the motor is only 31 mm diameter, and 54mm long, so I suspect it wouldn't draw near 10 Amps - but best to get one and measure the current under the expected load. \$\endgroup\$ Commented Nov 2, 2015 at 5:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.