[Harry] wrote in with his hack of the Crayola Light Designer. The Light Designer is a pretty unique toy that lets kids write on a cone-shaped POV display with an infrared light pen. [Harry] cracked one open and discovered it has a spinning assembly with a strip of 32 RGB LEDs for the display and a strip of photodiodes to detect pen position. These were ripe for the hacking.
The spinning assembly uses several slip ring connections to send power and data to the spinning assembly. [Harry] connected a logic analyzer to several of the connections to determine which lines were clock, data, and frame select (the strip is split into 2 16-led “frames”). He went on to reverse-engineer the serial protocol so he could drive the strips himself.
Instead of reverse-engineering the microcontroller on the product’s PCB, [Harry] decided to use a Leostick (Arduino Leonardo clone) to control the LEDs and spinner. He mounted the Leostick on the shaft of the spinning assembly, and powered it over the slip ring connections. After adding some capacitance to make up for noisy power from the slip rings, [Harry] had the POV display up and running with his own controller. Check out the video after the break to see the hacked POV display in action.