NeoKey BFF Header Pins

Cut two 7-pin sections of short male header pins.

Solder them with the legs facing the underside of the NeoKey BFF as shown here.

Lipoly BFF Headers

First cut two 7-pin sections of short female headers.

Solder them to the LiPoly BFF as shown.

QT Py Connection

Here's a trick for making the shortest stack possible with our boards. The QT Py and BFF form factor includes castellated pads. We can tin those and solder short male header pins to join the QT Py and the LiPoly BFF!

First, cut two 7-pin sections of short male header pins.

Then, tin the outer pads of the LiPoly BFF.

Hold the pins with pliers or tweezers to prevent cursing, then heat the pins to join them to the solder pads.

Push the plastic spacer up as far as it'll go.

Repeat for the other side of the board.

Repeat the tinning on the QT Py, then arrange the boards as shown, belly-to-belly with the LiPoly BFF battery JST connector on the same end as the QT Py's USB C connector.

Heat the pins to solder join the two boards as shown.

Stack 'em Up

Now you can connect the NeoKey BFF to the LiPoly BFF. Heed the ^USB This side to QT Py back silkscreen and press the header pins into the sockets as shown. (The NeoPixel is on the left side of the stack as shown in the photo above, with the LiPo power switch at the bottom.)