Continues Servo motor controller HELP

Thread Starter


Joined May 12, 2014
How to make a controller for my converted servo motor to continues rotation

so that i can control the speed and forward/reverse of the motor,(no programming)

i researched online and i found out about the lm555 timer IC but the two functions i want is made with two different circuit. i want to be able to use it in one circuit..

looking forward for your help


Joined Apr 11, 2010
Continuous rotation servos (hobby RC servos) are controlled in the same manner as a standard servo. Pulses of varying widths are applied every 20ms. These pulses vary from ~1300μs to ~1700μs.
* 1300μs rotates clockwise
* 1500μs stopped
* 1700μs rotates counterclockwise

To modify the servo speed, intermediate values of the pulse widths are used. For example, a width of 1475μs rotates the motor clockwise slowly.

The following link describes this with a picture as well:

This can be done with two 555s. The first 555 is wired as an astable oscillator running at 50Hz. It triggers a second 555 wired in monostable mode. A pot is used with this portion of the circuit to vary the pulse width. One such circuit can be found on the Seattle Robotics Society site.

Hope this helps.
Last edited: