What's better than a single LED? Lots of LEDs!

A fun way to make a small display is to use an 8x8 matrix or a 4-digit 7-segment display. 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.

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 two flavors - this mini 8x8 and a 4-digit 0.56" 7-segment. 

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 are photographed at the dimmest setting to avoid overloading the camera!), 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 (or a combination, such as four mini 8x8's and four 7-segments, etc) on a single I2C bus.

The product kit comes with:

• A fully tested and assembled LED backpack
• Ultra-bright 8x8 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.

Of course, in classic Adafruit fashion,they also have a detailed tutorial showing you how to solder, wire and control the display. They 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!

TECHNICAL DETAILS

• This board/chip uses I2C 7-bit address between 0x70-0x73, selectable with jumpers

Backpack Dimensions:

• 20mm x 28mm x 4mm / 0.8" x 1.1" x 0.2"
• Mounting Holes: 12mm x 22mm / 0.5" x 0.9"

Datasheets, schematic, EagleCAD PCB files, and Fritzing available in the product tutorial