The Adafruit LED Backpacks guide has been updated to include setup instructions for use with Python and CircuitPython.
What’s better than a single LED? Lots of LEDs! 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’ – 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 adorable LED matrix backpacks come in.
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, consistant 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. The backpacks come with address-selection jumpers so you can connect up to four mini 8×8’s or eight 7-segments (or a combination, such as four mini 8×8’s and four 7-segments, etc) on a single I2C bus.
The product kit comes with a fully tested and assembled LED backpack, a 4-pin header and the matrix of your choice. 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.