This project is adapted from USB LED fader from Objective Development. As servo motor uses PWM which is used to control LED light intensity. It only requires minimal firmware changes.

USB is firmware only which fits inside Atmega8 microcontroller. Because of this circuit becomes very simple – just few elements. Device is powered from USB so be careful as there is potential threat to damage USB port. I would suggest to attach an external power supply. The demo application is real fun. Once servo is attached on top of monitor, pointer attached to motor shaft points to mouse pointer location on screen.