I’m filming a video about my build an wanted to explain PWM motor drivers to my viewers. I understand the basics. Pulse Width Modulation means the width of a pulse is being modulated. Or in overly simple terms the motor is being told to turned on and off really quickly.
But where I’m confused is, with a microcontroller, the PWM signal is different than with an R/C receiver. And if you use am R/C receivers PWM signal with a board that is expecting a microcontrollers signal it won’t work right. What’s the difference?
Thanks for the help.
Hello @Everettdale,
Standard RC pulses are just a specialized form of PWM. A typical RC servo expects a signal every 20ms, however, this can vary from servo to servo. The pulse itself most often ranges from 1 ms to 2 ms, with 1.5 ms being the neutral position. Another difference could be the signal amplitude but thatcan also vary. You can find more information about this here.
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Thanks,
How is that different from say a motor speed controller that is expecting something other than a “servo signal”
When I bought the sabertooth 2X12 it came in 2 version, one specifically for R/C the other not. Should I assume that the expected pulse width would be longer? And the frequency different?
-dale
Sabertooths come in two different versions, one that is just for R/C and the other one that offers many options to control the servos: analog, serial and R/C inputs. All these control methods use different signals (you can check more info about this in the manual), but if you use the R/C control mode you’ll be using the same type of signal I mentioned in the previous post.
I suggest checking this video where he gives some details about the standard R/C servo control signal and shows the signal in an oscilloscope. If you’re planning on doing a video about PWM it would be really useful if you do something similar.
I also suggest checking this blog and although it’s not about servo control, it will help you understand PWM a little more
