That’s the question [Kathy] asked when she built this LED matrix light pen project. It looks simple enough – a 64-LED matrix illuminates as the pen draws shapes. But how does the circuit ...

Lumenoise is an audio synthesizer controlled by drawing with a light-sensitive pen on a CRT television. The pen is a self-contained module which connects to the TV via audio and composite video ...

A light-sensitive stylus wired to a video terminal used to draw pictures or select menu options. The user brings the pen to the desired point on screen and presses the pen button to make contact.