In a continuing effort to bring my interests in light and sound together, here's the Ray Gun. Inspired by a physics demonstration my dad gives, a laser is fired at a photo cell (from a $1.99 calculator). The pulse it gives off is modulated by interrupting the laser with a spinning screen. The pitch is changed by speed, controlled in this case with a model train controller. Endless hours of fun are to be had by routing the output into a multi-fx pedal.