This is my first question / post here. I have just begun researching motors and how they work, as they are necessary for a personal project.
I want to know how to control a motor so that it only rotates 45 degrees forwards and backwards. I would be implementing this by rotating a pole bi-directionally, with a fixed starting position. Any help would be appreciated.
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- 2$\begingroup$ You might want to check out stepper motors. $\endgroup$Solar Mike– Solar Mike ♦2021-10-27 10:14:09 +00:00Commented Oct 27, 2021 at 10:14
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1 Answer
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2 (Remote Control) RC servos usually have that type of functionality and they --usually-- use a PWM pulse to control the position.
The standard idea is (used to be) that you provide a digital pulse (either Hi or Low) 50 times per second (so the duration of the pulse is 20[ms]). Modern RC servos can be more forgiving and can have different times.
The duration of the high pulse is essentially the signal that controls the position. Typically for a 20ms duration, the central position is at 1.5ms (or 7.5 duty cycle).
figure: wikipedia
- $\begingroup$ Thanks, this was very helpful. $\endgroup$JayJay– JayJay2021-10-27 12:25:08 +00:00Commented Oct 27, 2021 at 12:25
- $\begingroup$ @JJ. Note that the electrical signals used in this answer is pretty arbitrary, especially in newer RC servos with microcontrollers. It's not directly driving the motor so there's no real physical significance or limitation to the electrical signal. There are electronics that "interpret" that signal as the position and then drive the motor accordingly to that position. $\endgroup$DKNguyen– DKNguyen2021-10-28 00:54:35 +00:00Commented Oct 28, 2021 at 0:54