Here is a full video guide to modifying a Turnigy TG9e Analogue Micro Servo for continuous rotation. Modifying a servo for continuous rotation opens up a number of possibilities for new Arduino projects, the modified servos essentially function as a PWM variable speed and direction motor which can easily be controlled by an Arduino or similar micro controller. The process is very similar for other servo models and different sized servos. Visit this link for the full guide along with purchase links for the tools and materials - http://www.the-diy-life.com/how-to-modify-a-servo-for-continuous-rotation/