speed control of dc motor using pulse width modulation raspberry pi
You may want to configure your motors to run at different speeds. This can be done by using Pulse Width Modulation (PWM) to adjust the speed. PWM simply defines a way of changing the voltage value of the signal by sending a series of pulses of equal value, and changing the width of each pulse. The wider the pulse, the higher the average voltage delivered to the receiver. The DC motors that you are using will respond to this higher average voltage by spinning faster.