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Miniature DC Motor Control

Posted by dahrich (My Page) on
Sun, Aug 14, 11 at 14:59

Hello:
I want a simple control for a small DC motor.
What I want to do is start the motor, have it run for about 2 seconds then stop. The thing is I want to stop it as acturately as possibly using a switch to cut off the voltage to the motor. But then I want to be able to start the motor, have it run in the same direction as before and then stop at the same switch.

I could use a timer and run the motor for 2 seconds and then stop when the timer "times out" but I'm afraid the motor will not stop at the same place each time and thus "drift" as it is started and stopped repeatedly.

Any thoughts are much appreciated.

Thanks in advance,
Richard


Follow-Up Postings:

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RE: Miniature DC Motor Control

What you are describing, is what's known as a servo-motor. A servo-motor uses feedback, usually from a pulse generator, to let the control circuitry "know" the exact position and speed of the motor. Of course this usually requires an IC based designed circuit to perform this.

Depending on what you are driving with the motor, you may be able to create a micro-switch based logic circuit to stop at the same point each time, similar to something like old-style ignition points. Something like a notch that the micro-switch could drop into and stop the motor. The next "on" signal would then restart the process.


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RE: Miniature DC Motor Control

yosemitebill:
thank you for your reply:
I have come across another site where I have gotten an answer.
I know about servos etc but didn't want anything that sophicated mainly becasue of the controler requirements and the cost. The solution I now have uses a flipflop and other electronic components which will be easy for me to build. Thanks again for your input.

Regards,
Richard


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