Mark’s Space has a great tutorial on how to scroll text across a matrix with a Raspberry Pi.
A friend requested if it was possible to scroll text across three 8×8 LED matrices, specifically this type from Adafruit, which are very bright.
So, I got to work.
These matrices uses a HT16K33 controller chip and communicate with the Pi via the i2c bus.
Adafruit have very good and detailed tutorials on how to solder it up and get i2c working between your Pi and your matrices.
Since we are having multiple matrices using the same i2c bus, we need to make sure that each uses a unique address. By default they will have 0×70 (hexadecimal notation). This value can be changed by brindgin the gap on some copper pads on the back of the matrix.
Adafruit Mini 8×8 LED Matrix w/I2C Backpack – Blue – 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. We have them in two flavors – a mini 8×8 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. Read more.
Each Friday is PiDay here at Adafruit! Be sure to check out our posts, tutorials and new Raspberry Pi related products. Adafruit has the largest and best selection of Raspberry Pi accessories and all the code & tutorials to get you up and running in no time!
We’ve just thrown the switch on a new Arduino library for creating LED matrix displays using NeoPixel LED strips, pixels or shields. All the functions in Adafruit_GFX are then available: lines, filled shapes, text, etc. The photo above shows three separate 10×8 matrices made from NeoPixel strip (240 pixels total — 4 meters of strip), tiled together into a single display…the library takes care of all the permutations! It’s also a great companion for our NeoPixel Shield.
Have you ever done something silly on a lark and then found it was a big hit? So it went with a “beta test” Halloween idea on the Adafruit Show & Tell last week of my electronic demon costume. This video is a summary of what was done there… and what I’m now scrambling to finish properly before the big day! Video on YouTube (please subscribe!) and Vimeo.
Some updates since this was shot: a Ustream chat participant during Show & Tell suggested using a paintball mask as a base. I’m currently working on the faux ribcage idea… there may be enough space to move most of the electronics there and have just batteries in the pack. We shall see!
HAPPY HALLOWEEN! Each day this month (Monday-Friday) we’re going to have a special “Electronic Halloween” post here on Adafruit. It will be a hack, mod, project or something we’ve found that combines all the best things about electronics and Halloween.
I spent Tuesday afternoon strolling the expo floor at the Embedded Systems Conference (now one of several concurrent events under the “DESIGN West” banner). It’s a big industry show for component electronics and test equipment…mostly out of my league, to be honest…but nonetheless interesting to drop in and see what’s new and where things may be headed.