Solder pin headers to the Feather RP2040 and MIDI FeatherWing. Solder socket headers to the FeatherWing Doubler.

Solder rotary encoders to the four quad rotary encoder breakouts for a total of 16 rotary encoders. You can use the optional 3D printed NeoPixel riser described on the 3D Printing page to diffuse the NeoPixel underneath the rotary encoder.

The quad rotary encoder breakouts need to have their address jumpers cut to change the I2C address of each board:

• Breakout 0: default address 0x49 (no jumpers cut)
• Breakout 1: address 0x4A (jumper A0 cut)
• Breakout 2: address 0x4B (jumper A1 cut)
• Breakout 3: address 0x4C (jumpers A0 and A1 cut)

Cut, splice and tin four pieces of wire. These wires will be used to connect the interrupt pins on the quad rotary encoder breakouts to the Feather RP2040 on the FeatherWing Doubler. Solder the wires to the following pins:

• D5 (blue wire)
• D6 (green wire)
• D9 (white wire)
• D10 (yellow wire)

Solder the other ends of the wires to the INT pins on the quad rotary encoder breakouts.

• Pin D5 to breakout 0 (0x49) INT (blue wire)
• Pin D6 to breakout 1 (0x4A) INT (green wire)
• Pin D9 to breakout 2 (0x4B) INT (white wire)
• Pin D10 to breakout 3 (0x4C) INT (yellow wire)

The rest of the wiring is done using STEMMA QT cables. The quad rotary encoders and OLED display are daisy chained to the Feather RP2040.

• Feather STEMMA port to breakout 0 (0x49)
• Breakout 0 (0x49) to breakout 1 (0x4A)
• Breakout 1 (0x4A) to breakout 2 (0x4B)
• Breakout 2 (0x4B) to breakout 3 (0x4C)
• Breakout 3 (0x4C) to OLED display