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.
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
