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Unread 20-04-2005, 08:18
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Re: Electronic Speed Controllers for DC Motor

Quote:
Originally Posted by Max Lobovsky
It's only 1 amp and its the approximately the correct voltage so I wonder if you could drive it directly from the pwm? I don't really know the properties of the pwm signal, but if it goes from a duty cycle of ~0% - ~100%, it might just cut it. If not, I am pretty sure that the RC world does use the same pwm signal. I wish I could say for sure, but if you could find some rc speed controller to test it on, I would.
No, this won't work. The PWM signal output from the RC is encoded with the direction and magnitude, which is decoded by the ESC to drive the motor. The frequency of the output to the motor is around 20kHz with variable duty cycle.

I think the mini-RC can output a 20kHz square wave, but you would need an external H-bridge to drive the motor. By controlling the duty cycle of the output you control the speed of the motor. A full bridge would have one input for the direction and another for the speed. For a small motor this would be an inexpensive option assuming you can figure out how to configure the PWM outputs on the RC.