Let's Make a Simple Servo Controller Using 555 Timer

This project will show how to make a simple driver for  servo motor using 555 Timer click here.We use 555 timer as PWM signal generator.


About Servo ?

Servos are extremely useful in robotics  and are extremely powerful for their size. Servo has a DC motor, a series of gears, potentiometer, and control circuit. It has three pins, like signal  pin for PWM, Vcc (+) pin for power supply, and Ground (-) pin. We need 5 Volt DC and PWM signal to be running the servo. The wires varies with different brands the pictures below show the socket configuration for Futaba (equal with GWS servo) and Hitec.

Reference : http://www.coastalplanes.com/articles/pinout.htm

Servo PWM Signal 


Servo motor rotation angle is set based on the pulse width that sent to it. The folowing picture show that if the servo gets 1.5 ms high pulse every 20 ms, wiill make the servo turn to 90 degrees. If the pulse shorter than 1.5 ms, then the motor will turn the shaft to closer to 0 degress. If the pulse is longer than 1.5ms, the shaft turns closer to 180 degress.

PWM Signal

555 Timer Circuit

555 Timer can generate the PWM signal to control the angle of servo rotation. The circuit below from http://sarconastic.tripod.com/servodriver.html  is a 555 Timer  PWM generator.

To learn more about the schematic : http://sarconastic.tripod.com/servodriver.html

Testing