What’s better than a single LED? Lots of LEDs! Matrices like these are ‘multiplexed’ — so 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. 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 lovely LED matrix backpacks come in. We have them in three flavors — a mini 0.7″ 8×8, a small 1.2″ 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.
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 (the images above are photographed at the dimmest setting to avoid overloading our camera!), 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.
The product kit comes with:
- A fully tested and assembled 1.2″ LED backpack
- 1.2″ 8×8 Matrix Square Pixel in Amber
- 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.
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 eying matrix displays but hesitated because of the complexity, this is the solution you’ve been looking for!
The Arduino playground has a nice set of tutorials introducing the MAX7219 and 8×8 LED matrices
Using a high power shift register to drive 8×8 matrices with a NETduino
- 31mm x 312mm x 7mm / 1.2″ x 1.2″ x 0.3″
- Height without Pins: 7mm / 0.3″
- Weight: 7.65g
- 41mm x 33mm x 2mm / 1.6″ x 1.3″ x 0.08″
- Weight: 5.2g