What's better than a single LED? Lots of LEDs! A fun way to make a small colorful display is to use a 1.2" Bi-color 8x8 LED Matrix. 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. Here at Adafruit we feel your pain! After all, wouldn't it be awesome if you could control a matrix without tons of wiring? That's where these adorable LED matrix backpacks come in. We have them in three flavors - a mini 8x8, 1.2" Bi-color 8x8 and a 4-digit 0.56" 7-segment. They work perfectly with the matrices we stock in the Adafruit shop and make adding a bright little display trivial. 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.
The product kit comes with:
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.
Of course, in classic Adafruit fashion, we also have a detailed tutorial showing you how to solder, wire and control the display. We even wrote a very nice library for the backpacks so you can get running in under half an hour, displaying images on the matrix or numbers on the 7-segment. If you've been eyeing matrix displays but hesitated because of the complexity, his is the solution you've been looking for!
See our Distributors page for a complete list of distributors.