The QT Py stacks back-to-back with the power breakout BFF using headers. The NeoPixel stars plug into the Stemma port on the QT Py: Red to +5v, Black to G, and yellow to DI. 

The yellow stemma wire connects to pin 19 on the QT Py, so that's the number we'll enter under LED Settings in WLED.

This wiring method is fine for a small project like we've got, using only 17 pixels. If you have more than around 30 pixels in your project the Stemma's tiny wires won't carry enough current to get your pixels really bright. This is a simple and lovely wiring strategy for smaller projects. Check out this guide on powering pixels if you've got a bigger dream in mind.

NeoPixel strips have an IN and OUT end. Be sure you're connecting to the IN end or the pixels won't light up. This is sometimes inconsistent with different lots of pixels so it's a good idea to test before committing with a solder joint. On the build page I'll give some tips about how to figure out which end is which.

The USB port on the QT Py is now available to use as a charging port. This BFF breakout adds USB battery charging to your project. Neat!