Actions
Forum Thread Details
  • Replies 13 replies
  • Subscribers 402 subscribers
  • Views 1114 views
  • Users 0 members are here
Related

Arduino and Electric Motor

iseeall

I am new to the site. I have been having a blast with some projects with my arduino.  I do have a question that I am uncertain about.  I would like to control an external electric motor that already has its own power supply, such as a box fan.  I am not an electrical engineer by any means, just a tinkerer.   I would like to control the speed of the fan programatically.  But not sure if I can just interrupt the power flow to it and use something similar to like a dimmer.  Or if I need to use some sort of power regulating relay sheild. 

 

Any suggestions and help are appreciated!  Again, thanks for the great tutorials and I hope to be on the site more!

Parents

  • If it's a DC fan, this tutorial from Oomlout might help:

    http://www.oomlout.com/oom.php/products/ardx/circ-03

     

    See the "Making it Better" section at the bottom on how to control speed.

     

    Depending on your motor, you might need a more powerful transistor to match. It might be a good idea to start with something small like a power-toothbrush motor just to help figure things out.

     

    Hope that helps!

     

    Cheers,

    -Nico

  • in reply to ntewinkel

    That looks like what I was hoping was going to be the case. 

     

    I am going to attempt to do this with some smaller motors (toothbrush, rc car, ect) and then I would like to step up.  Obviously something like a box fan or even a small desk fan will require something larger to handle the power.  Any suggestions on the circuit layout for that?  You mentioned larger transistors.  Sounds like maybe this is something you might have done? image

     

    Thanks again!

  • in reply to iseeall

    Hi Jason,

     

    I haven't tried anything much bigger yet, but have run into trouble with slightly bigger motors just not working with that oomlout circuit with the recommended transistor, even when using a second power supply to run just the motor. On that note, if your motor doesn't run, you can test the circuit with an LED in place of the motor.

     

    To run with a separate power supply, you can use the same circuit - just connect the breadboard +/- rails to the new power supply, and connect the Arduino ground to the ground rail. Don't connect the Arduino 5v to anything (ie, remove that connection from the original circuit), and pin9 stays on the transistor where it was.

     

    Cheers,

    -Nico

  • in reply to iseeall

    I just thought I'd try that circuit again, but I get the same results as before: Only one of the little motors actually works with that Oomlout circuit (even when using an external supply to run just the motor circuit).

     

    The other motor works fine when connected directly to 5v and gnd, but not when through the pn2222 transistor. A while back I checked, and the motor didn't seem to draw more amps than the transistor was rated for (I think that's 600mA, and the motor was like 400mA), so I don't know what's up with that!

     

    So I'm hoping someone else will have some brilliant advice as to what kind of transistor can be used, if it is indeed possible to use a transistor, and/or how to properly run a bigger motor image

     

    Cheers,

    -Nico

  • in reply to ntewinkel

    is there a way to have something regulating the power of the other power supply, and that regulator controlled by the arduino?

     

    external power ->  arduino controlled regulator ->  electric motor

  • in reply to iseeall

    This tutorial says a TIP120 can be used:

    http://playground.arduino.cc/Main/DCMotorControl

     

    It looks like the relay is to control forward/backward, and the TIP120 controls speed...

Reply Children