For the STEMMA QT version, you can solder the headers on, or you can simply use a STEMMA QT cable!

  • Backpack + (VCC) to microcontroller 5V (if using a board with 5V logic, otherwise use 3V for boards with 3V logic) (red wire)
  • Backpack - (GND) to microcontroller GND (black wire)
  • Backpack D (SDA) to microcontroller SDA (blue wire)
  • Backpack C (SCL) to microcontroller SCL (yellow wire)

To assemble the LED backpack, follow along below.

Soldering the 7-segment display is the same for the STEMMA QT version and the original version.
When you buy a pack from Adafruit, it comes with the fully tested and assembled backpack as well as a 7-segment display in one of the colors we provide (say, red, yellow, blue or green). You'll need to solder the matrix onto the backpack but it's an easy task.
Remove the parts from packaging and place the LED matrix OVER the silkscreen side. DO NOT PUT THE DISPLAY ON UPSIDE DOWN OR IT WONT WORK!! Check the image below to make sure the 'decimal point' dots are on the bottom, matching the silkscreen.
Turn the backpack over so it is sitting flat on the matrix.
Solder all 14 pins.
Clip the long pins.
Now you're ready to wire it up to a microcontroller. We'll assume you want to use a 4pin header. You can also of course solder wires directly. Place a 4-pin piece of header with the LONG pins down into the breadboard.
Place the soldered backpack on top of the header and Solder 'em!
That's it! now you're ready to run the firmware!

This guide was first published on Jul 29, 2012. It was last updated on Sep 28, 2022.

This page (Assembly and Arduino Wiring) was last updated on Jan 21, 2020.

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