LED backpack displays are a great way to add a simple, bright LED display to your project. These displays get their name because of the controller chip attached to the back of them like a ‘backpack’. This HT16K33 controller can drive up to 128 multiplexed LEDs in matrix, bar graph, 7-segment numeric, and even 14-segment alpha-numeric configurations. It handles the LEDs with a constant-current driver so the light is bright and consistent even if the power supply varies.
Best of all, the controller exposes a very simple I2C-based interface which is easy for a small-board computer like the Raspberry Pi or BeagleBone Black to access. This guide will show you how to install and use the Adafruit Python LED backpack library for driving LED backpack displays from a Raspberry Pi or BeagleBone Black!