This version of the LED backpack is designed for these bright and colorful bi-color bargraph modules. Each module has 12 red and 12 green LEDs inside, for a total of 24 LEDs controlled as a 1×12 matrix. We put two modules on each backpack for a 24-bar long bargraph (48 total LEDs).
This backpack solves the annoyance of using lots of pins or a bunch of chips by having an I2C constant-current matrix controller sit neatly on the back of the PCB. The controller chip takes care of everything, drawing all 48 LEDs in the background. All you have to do is write data to it using the 2-pin I2C interface. There are three address select pins so you can select one of 8 addresses to control up to 8 of these on a single 2-pin I2C bus (as well as whatever other I2C chips or sensors you like). The driver chip can ‘dim’ the entire display from 1/16 brightness up to full brightness in 1/16th steps. It cannot dim individual LEDs, only the entire display at once.
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — Lessons Learned Scaling Airbnb 100X
Wearables — Start with a sketch
Electronics — When do I use X10?
Biohacking — What I Learned from Weighing Myself 15 Times in a Day
No comments yet.
Sorry, the comment form is closed at this time.