After observing my son’s interest in the glowy buttons on my Rigol DS1102E, I decided to design an interactive toy for him utilizing that type of button.
SparkFun sells 2 x 2 and 4 x 4 translucent silicone button pads that accommodate a standard 5 mm through-hole LED. Adafruit now sells a smaller dimension 4 x 4 button pad, but it can only accommodate 3 mm LEDs. I’m not aware of any RGB LEDs that come in that package size, but I may see how well it works with surface-mount RGB LEDs in a future project.
My requirements are:
- 4 x 4 translucent button pad
- 5 mm through-hole diffused lens RGB LEDs
- N-key rollover to prevent jamming and ghosting
- Arduino compatible micro-controller for easy programming
- AA battery powered
- DC boost circuit to extend useful battery life, inspired by projects like Ray’s AA Saver
- Individual on/off control of LEDs through shift registers or LED drivers
- Single 2-layer PCB
- Buzzer capable of playing musical notes spanning a few octaves