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Electronics => Electronics => Topic started by: zs on July 13, 2007, 04:34:46 AM

Title: stepper motor
Post by: zs on July 13, 2007, 04:34:46 AM

Hi guys,

I'm using a phototransistor IR sensor on a stepper motor to locate IR beacon. I modified the stepper motor to rotate 360 degree in clock wise direction. But I want the stepper motor to return to it's starting point in  counter clockwise. How can I do that? plz, help. Thanks.

ZS

Title: Re: stepper motor
Post by: Steve Joblin on July 13, 2007, 12:35:50 PM

Do you mean "servo" motor or "stepper" motor?  They are two very different things.  I'm not quite sure what kind of stepper motor you have and what kind of modifications you made to it (as most stepper motors are designed to spin 360 degrees.

If it is a "servo" motor you are talking about, sending a 1.5 ms pulse every 20 ms should center the servo causing it to stop.  sending a shorter pulse (like 1 ms every 20 ms) will make it rotate in one direction, while sending longer pulses (like 2 ms every 20 ms) will make it rotate the other direction.  the closer you get to 1.5 ms pulses should cause the rotation speed to decrease (so sending a 1.4 ms pulse every 20 ms should cause it to rotate slower than sending a 1.2 ms pulse every 20 ms).