What's better than a single LED? Lots of LEDs! A fun way to make a
small display is to use a 4-digit 7-segment display. Matrices like
these are 'multiplexed' - so to control all the seven-segment LEDs you
need 14 pins. That's a lot of pins. 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, 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. The backpacks come with address-selection jumpers so
you can connect up to eight 7-segments on a single I2C bus (2 IO-Pins
The product kit comes with:
* A fully tested and assembled LED backpack
* Ultra-bright 4-digit 0.56" tall red seven-segment display, blue
* 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 eyeing matrix displays
but hesitated because of the complexity, this is the solution you've
been looking for!