Trim the sensor legs about halfway down. 

With the sensor bump facing you and the legs pointing down, slip a red wire onto the leg on the right, a black wire to the middle leg, and a yellow wire to the leg on the left.

Cover the connections with heat shrink so they don't short out.

Solder to the Feather as follows:

• IR sensor red --> USB (if powering via USB) or BAT (if powering via the JST connector)
• IR sensor yellow --> Feather pin 13

Leave the black (G) wire unconnected for now.

To give a little more flexibility for placement, I soldered around 8" of wire onto the NeoPixel strip. This will give me some options about where to place the Feather board and IR sensor inside the sign. 

Strip the 4th wire from the ribbon cable. Find the "in" end of the strip (labeled DI usually) and solder the striped wire to red (or the +5v pad), the middle wire to white (or the DI pad), and the remaining wire to black (or the G pad).

Connect the other end of the ribbon cable to the Feather as follows:

• Red (striped) wire to USB (if powering via USB) or BAT (if powering from the JST connector)
• White (middle) wire to 13

You're left with two black wires - one from the IR sensor and one from the NeoPixel strip, which both need to connect to the G pin on the Feather. The easiest way to do this is to splice the two wires together with a third wire, then connect this wire to the G pin on the Feather.

Plug your Feather in to power. If all goes well, your lights will come on in a solid yellow. 

Grab your 44-key remote and press some buttons to see if it responds.