The photographs here mostly depict the 4x4 case being assembled. 8x8 is similar enough (just a few extra pieces) that we’ll just highlight the differences where necessary.

For a wireless project, the switch must be installed though this piece in a particular back-to-front direction. It’s a bit too much to describe in words, so have a look at the photographs, making sure your parts are oriented the same way.

The locking washer and nut go “on top.” Also, the switch has a small protrusion which fits through a corresponding hole on this piece. This keeps the switch from spinning around when you tighten the nut.

Tethered projects do not require the switch, you may ignore this step.

All Your Base

We’ll start from the bottom and work up…

Note: some versions of this kit don’t accommodate the Feather nRF52840 board (which came later) — a cutout was added to later kits. If you have an incompatible combo, you can try desoldering the debug header from the Feather board…or, if you have access to a laser cutter or 3D printer, you can make a replacement bottom piece from files on the “Downloads” page. DO NOT drill acrylic, it requires a special kind of drill bit!

Collect all the M2.5 hardware…this includes the four smaller screws and nuts, plus four standoffs.

What’s peculiar about this case is that the Feather board sits face down…it’s behind the acrylic here. Turn this bottom piece over and around until you find the orientation that fits the battery socket, reset button and all four mounting holes, like in the picture.

The board installs upside-down like this so the reset button is still accessible with a pen or screwdriver!

Insert four M2.5 screws, turn the base piece over and lay it on your work surface (temporarily tape over the screw heads if you have difficulty with this step).

Add four spacers, lay the Feather board face-down over the screws, then add four nuts.

On some Feather boards, two mounting holes are partially obscured by the wireless module.

In this situation, it’s okay to use only the two mounting holes near the USB port.

Next you’ll need these four threaded standoffs, and four of the eight M3 screws.

The screws come up from below the case, with the standoffs on top. It’s the same for a tethered or a wireless project.


These case pieces don’t have labels or specific names…but they do have distinct shapes that fit a certain way.

Pay attention to the slots and tabs on each piece, and refer to the photos to get each item in its correct position.

The case is double-walled in order to hold the Trellis board in place. We’ll do the “inner” walls first…

Look for these two side pieces and slot them into the base. Then the front and back inner walls will slot into these. If it’s a wireless project, one of these inner walls will have the switch attached. It fits into a cutout in the base.

The 8x8 case is similar, but has four extra pieces providing some support down the middle.

These smaller horizontal and vertical supports are keyed in such a way to only fit in their corresponding holes. You’ll want to do the vertical supports and sides first, then add the horizontal supports. Then continue just like a 4x4 case.

It will all seem a little wobbly at this stage. That’s normal. Once the NeoTrellis and top case are installed, everything becomes much more solid.

For a wireless project, there’s just enough space for a 500 mAh LiPoly battery in the corner away from the Feather and switch. (Up to 2500 mAh on the 8x8 NeoTrellis, positioned at center.)

Double-stick tape — either the foam or cellophane type — can help keep this in place during assembly. Not absolutely vital, just handy if it’s something you have.

The outer walls install in a similar order. But, with the inner walls in place, these outer pieces won’t just drop into place…you’ll need to tilt them up into place, or lift the inner pieces slightly to get all the tabs and slots to lock.

Plug the STEMMA connector into the NeoTrellis socket.

(If you built without the STEMMA cable, the NeoTrellis board will already be attached to the Feather and/or switch directly, using the edge solder pads.)

Before closing it up, this is a good opportunity to connect a USB cable and confirm once more (now with the Trellis connected) that the Feather board powers on and (if building a wireless project) that the switch works and the battery charge LED comes on.

Top Layers

Orient the enclosure so the USB port is at the top, then carefully work the Trellis PCB into position, minding any pinched wires as you go.

The numbers on the Trellis PCB should appear upside-down with respect to the case, i.e. “16” will be at the top-left. You may need to adjust for this in software. This provides clearances for the parts inside with the slimmest possible case.

Compensating for NeoTrellis Orientation

The orientation of the NeoTrellis PCB inside the case requires adopting one of two strategies…EITHER:

  • Operate the NeoTrellis case with the USB port at the bottom/front (no big deal for wireless, but might be strange for a USB-tethered project). OR…
  • Keep the USB port at the top/back and compensate for the rotation in software. Pixel/button 0 is at the bottom-right now. To remap button #n from old to new orientation, use 15-n instead.

Carefully now…lower the Trellis PCB until it sits flush against the inner walls. You’ll probably need to stuff some wires back in using the tip of a screwdriver. If anything is pinching or binding…stop, lift up the Trellis board, find what’s tangled and give it another go. Don’t force anything.

Install the elastomer button pad over the Trellis PCB. This pad has little “nurnies” that lock into corresponding holes on the PCB, so it has to be turned a certain way before it will sit flush.

Then add the top clear piece. This will probably require a little wiggling to get all the tabs and slots to lock together.

Finally, add the topmost black layer.

The top is held in place with the remaining four M3 screws. It’s easier once the first screw is in place…you won’t need to keep holding it together like a sandwich.

Add four self-stick rubber “toe beans” to the bottom so it stays in place on your desk.

You’re done!

This guide was first published on Aug 28, 2019. It was last updated on Aug 28, 2019.

This page (Case Build) was last updated on Aug 28, 2019.

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