A fun way to make a small display is to use an 8×8 matrix or a 4-digit 7-segment display. Matrices like these are ‘multiplexed’ – to control 64 LEDs you need 16 pins. That’s a lot of pins, and there are driver chips like the MAX7219 that can control a matrix for you, but there’s a lot of wiring to set up and they take up a ton of space. After all, wouldn’t it be awesome if you could control a matrix without tons of wiring? That’s where these lovely LED matrix backpacks come in.

The matrices use the constant-current drivers for ultra-bright, consistent color, 1/16 step display dimming, all via a simple I2C interface. These 1.2″ matrix backpacks come with three address-selection jumpers so you can connect up to eight 1.2″ 8×8’s together (or a combination, such as four 1.2″ 8×8’s and four 7-segments, etc) on a single I2C bus.