Matrices like these are 'multiplexed' - so to control all the 128 LEDs you need 24 pins. That's a lot of pins, and there are driver chips like the MAX7219 that can help control a matrix for you but there's a lot of wiring to set up and they take up a ton of space. Control a matrix without tons of wiring with these adorable LED matrix backpacks. It's called a Bicolor LED, but you can have 3 colors total by turning on the red and green LEDs, which creates yellow. That's 3 colors for the price of 2!
The matrices use a driver chip that does all the heavy lifting for you: They have a built in clock so they multiplex the display. They use constant-current drivers for ultra-bright, consistent color, 1/16 step display dimming, all via a simple I2C interface. The backpacks come with address-selection jumpers so you can connect up to four mini 8x8's or eight 7-segments/bicolor (or a combination, such as four mini 8x8's and two 7-segments and two bicolor, etc) on a single I2C bus.
- Fully tested and assembled LED backpack
- 1.2"" Bi-color 8x8 LED Matrix
- 4-pin header
A bit of soldering is required to attach the matrix onto the backpack but its very easy to do and only takes about 5 minutes.