Thread: Servo question
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Unread 22-01-2013, 21:23
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Re: Servo question

Quote:
Originally Posted by Sparks333 View Post
I think I see the confusion. I'm afraid servos are a bit more complex than that - they depend on seeing a pulse-width modulated (PWM) input as sort of a heartbeat, so they can tell the difference between being given a signal and being unplugged (it's a safety thing, and it's good, trust me). A typical hobby servo PWM signal pulses at 50 Hz and has a pulse width of between 1 mS and 2 mS - the wider the pulse width, the greater the angle (with 1.5 mS being neutral). Unfortunately, no servo I know of will respond in any way to a constantly-high or constantly-low signal - they specifically require that they be pulsed at 50 Hz (though that spec can be a little loose) with a duty cycle between 1 mS and 2 mS. If you want dead-simple low-power full-CW or full-CCW and don't have the patience to do hobby servos, you might try wiring to a motor directly to a double-pole double-throw switch that either makes the motor rotate CW or CCW, and use limit switches to break connection when you get to your desired angle.

Luck,

Sparks
Thanks for that explanation, I didn't realize the safety feature. I think I may try the limit switch idea, thanks for all the help!