Set Addresses

To use four NeoSliders on one I2C bus, each board needs a unique address. You will cut the traces on three of the boards to set them.

Set them to:

  • 0x30 (default, don't cut any traces)
  • 0x31 -- cut trace A0
  • 0x32 -- cut trace A1
  • 0x33 -- cut traces A0 and A1

More info is available here.

The NeoKey 1x4 has a default I2C address of 0x38 so you don't need to adjust that one.

NeoKey Prep

Insert the keyswitches through the keyplate (3D printing file linked above), minding the orientation so they'll fit into the hot swap sockets. Position them so the "window" in the switch is above the reverse-mount NeoPixels.

Then, carefully align the legs with the NeoKey board and insert them all at once, squeezing with even pressure.

Connect the Boards

Connect the Feather, NeoKey, and NeoSliders as shown using the STEMMA QT cables.

Cut the Enclosure

Use the linked .svg file to cut the case parts from acrylic. You can do this on a laser cutter or CNC machine, by hand with a saw and drill (print the .svg as a template), or send the .svg file to a service bureau for cutting.

Connect the Base

Use the M2.5 screws and nuts to secure the NeoSliders to the case bottom as shown.

NeoKey Mounting

Mount the NeoKey onto the screws as shown, by threading the nuts on first, and then sliding the board and keyplate holes over the screws. This places the board at a good height and it will stay put in use, no need for longer screws or top nuts.

Mount the Feather

Use short screws and nuts to mount the feather board as shown, with the USB port facing the back of the board, over the notched cutout.

Top Plate

Mount the M3 standoffs from the bottom with short M3 screws.

Place the top plate over the controls, then secure with four more screws.


Place the four fader caps and keycaps onto their respective controls.


Stick four adhesive bump-on feet under the enclosure to prevent sliding.

Plug in USB and you're ready to go!

Use the Neocontroller

Plug in the Neocontroller to your computer over USB-A to USB-C data/power cable. For typical MIDI use, simply select the Feather RP2040 MIDI device. To use with Lightroom Classic, first download and install the free MIDI2LR plug-in as shown here.

There are plenty of good setup and configuration videos out there, such as this.

Here it is in action:

This guide was first published on Dec 19, 2021. It was last updated on Dec 19, 2021.

This page (Build and Use the Neocontroller) was last updated on Jan 19, 2022.

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