In this video, [Jack] talks about various types of pulse width modulation (PWM). You can use PWM to control the speed of a motor, the brightness of a LED, or to generate analog waveforms.

His setup uses an Atmega8 micro-controller which controls a small 12V 50N coil using pulse-width-modulation (PWM). A hall effect sensor (Allegro A1302) mounted inside the coil detects the ...