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Topic: Controlling Brushed DC motor (Read 5442 times) previous topic - next topic

Bowez

Hello everyone,

I have a brushed DC motor that I want to power with a 3 cell 11.1volt 1320mah battery.
I would like to control the speed of the motor using a potentiometer, but I want to do it through the Arduino Board.

From what I understand, its possible to get a speed controller of some type between the motor and the battery, and have the Arduino PWN pin tell the controller how much juice to feed to the motor, hences controlling the speed, is that correct?  If so, what is the best way to do this? I don't know much about speed controllers.


My background is in Animation, I've only had one electronics class in my life, so my knowledge is extremely limited.

I appreciate any and all help and insight.
thank you
-joe

trialex

The arduino playground http://www.arduino.cc/playground/Main/InterfacingWithHardware#Output has a link to a diagram that shows you all you need to know about controlling a DC motor using a L293 IC. You sound like you know a bit about PWM - shouldn't be hard to get it working using the example (OK it's in German - but you'll get it)

http://gestaltung.fh-wuerzburg.de/blogs/exint_ws06/?p=505

The datasheet  for the L293 is useful too

MikMo

You can connect the motor through a TIP120 transistor and a diode.

Check here: http://itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads

Bowez

Thanks for the help!  I looked into both methods, and ordered the parts needed.  So far I've tried the method that uses the TIP120 transistor and it works!!  I'm going to try the L293 IC next!

thanks again

-joe

MikMo

The advantage of the L293 over the transistor solution is that with the L293 you also have control over direction of the motor, which might or might not be important depending on the application. The advantage of the transistor solution is the super low parts count and of course it's cheaper.

Bowez

Good to know, I don't need to reverse the motor, so the Transistor sounds like the best choice.

I hooked my multimeter the connection point for the motor, I noticed that when my potentiometer is turned down, the voltage is at 6V, as I turn the pot it immediately jumps from 6v to 9v, then it slowly climbs up to 12v.

Any idea why it skips from 6v to 9v?  If I remove the power to the arduino board it still sits at 6v, so I assume thats how much it lets through be default.

-joe

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