Peel the backing paper off both sides of all the laser-cut parts (11 in the 4x4 kit, 15 in the 8x8 kit). It’s easiest to start at a corner, catching the edge of the paper with a fingernail.

The laser-cutting process can leave some paper soot at the edges. If you like, wash these parts off with soap and water, just be absolutely certain that all the parts are completely dry before assembling!

Use only soap and water when cleaning these parts. Some chemicals, including rubbing alcohol and alcohol wipes, will damage the plastic!

If using the STEMMA cable, cut it in half along its length, strip and tin the ends of the wires.

For a tethered device, you only need the half with the plug.

For a wireless device, save the other half. Clip off the header pins, strip and tin both ends of these wires.

You can still build the kit if you don’t have the STEMMA cable but have other wire around…you’ll be soldering directly to the pads on the edges of the Trellis board in that case, it’s not quite as plug-in simple.

Here’s how the wiring looks with a STEMMA cable on a Feather M4 board to be used in a “tethered” configuration.

Wires approach from the bottom and are soldered on top. This is important later.

Here’s a back-side view of the switch, showing where wires will connect.

Here’s how the wiring looks with a STEMMA cable on a board to be used in a wireless configuration.

Wires approach from the bottom and are soldered on top. This is important later.

Some Feather boards have a single GND pin, others have more than one.

A switched project requires two GND connections. If your Feather only has one GND pin, the STEMMA wires are thin enough that you can twist two together before tinning the ends, and still have it fit through the single GND connection.

An 8x8 setup is comprised of four 4x4 NeoTrellis…es? NeoTrelli?

Use blobs of solder across the A0–A4 pads to assign each 4x4 NeoTrellis a unique I2C address. Usually this involves leaving one untouched, bridging “A0” on the second, “A1” on the third, and both A0+A1 on the fourth (though you can use whatever combination you want, as long as each is unique…it’s configurable in software).

The four sub-Trelloids then need to be soldered together by joining the five pads along their common edges (SDA, SCL, etc.). Although it’s possible to do this with just solder alone, you’ll likely find it both easier and more durable to solder small pieces of bare wire across these pads.

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.

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.

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.)

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.

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!