555 PWM motor speed controller
Here is a project I did after the arduino PWM motor controller.
A 555 timer doesn't have enough power output to drive a motor alone, so a TIP120 transistor is used as a gate for the power source (a 9V battery).
I wanted to adjust the motor speed live, so I used a potentiometer to vary the duty cycle.
Here is the schematic:
This is my working breaker board:
Here are the oscillograms, with blue across the motor leads and the red across the 555 time output.
For the calculations, I used the calculator found here:
http://www.ohmslawcalculator.com/555_astable.php