Soldering the rotary encoder to the breakout PCB. Then, solder nine pin headers to the breakout PCB's pins.

Trim a row of socket headers to nine sockets. These will be used to plug the rotary encoder into the Feather nRF52840.

Solder the trimmed socket header to the Feather nRF52840, beginning with pin 13. Pins Bat, EN and USB should remain unsoldered. After soldering, the rotary encoder's breakout can plug directly into the Feather.

Cut and strip four pieces of wire. Use three different colors to differentiate the connections.

• Two pieces in color 1 (black): GND connections
• One in piece in color 2 (blue): pin A1
• One piece in color 3 (yellow): pin EN

Twist two pieces of wire together for the GND connection. Solder the wires into the GND pin on the Feather nRF52840.

Solder the blue wire to pin A1. This will be the input for the mode switch.

Solder the yellow wire to pin EN. This will be the on/off switch connection.

Tin the ends of each piece of wire with solder.

Cut four pieces of heat shrink. Place one piece onto each wire.

Solder a GND wire to pin 1 on the on/off switch. Solder the yellow wire to the center pin on the on/off switch. The on/off switch should be connected to pin EN.

Solder a GND wire to pin 1 on the mode switch. Solder the blue wire to the center pin on the mode switch. The mode switch should be connected to pin A1.

Apply the heat shrink to the switches' pins to prevent any shorts.