First we'll need to measure wires for each component so its long enough to reach each mount inside the enclosure.
The Slide Switch will connect to the Feather board and will need to be 70mm for the GND and 50mm for the EN pin.
CharliePlex Featherwing connects the Feather. Connections for SDA and SCL wires will need to be 70mm long. Measure the 3v and GND connections to both be 80mm long.
LIS3DH connects to the Feather and will need all four connections to be 40mm long.
Assemble Slide Switch
A slide switch is used to tie the enable and ground pins so we can turn off the 3 volt regulator, while still enabling you to charge the lipo battery through a USB cable.
Use heat shrink to prevent the pins from touching other components when inserted into the enclosure.
We used 1x45mm sized heat shrink tubes. You can use the side of the soldering iron to heat up and shrink the tubes around the solder connections.
Use a flush diagonal cutter to remove the unused third pin.
The LED matrix is free-wired to the Adafruit Feather to make the assembly as slim as possible.
We can solder the wires from the bottom side of the boards to make them easy to attach to each other. This also gives room for the battery to fit between the two boards.
We used 30AWG silicone coated wires to provide flexibility and durable handling.
Solder Slide Switch
Next, we'll solder the slide switch to the EN and GND pin on the top of the Feather board.
The LIS3DH is soldered in the same way, with the wires underneath the board.
We can then solder connections for SDA, SCL, GND and 3V to the top side of the Feather board.
Later, will mount it to the top of the Feather board with the help of a 3d printed mount.
This 3d printed mount will secure the LIS3DH to the top of the Feather board.
We'll use M2x4mm screws to connect the LIS3DH to the 3d printed mount.
Next we'll fasten the the 3d printed mount on top of the feather board. We'll use the two mounts close to the prototyping area.
Use two M2x8mm screws so they can reach through the Feather and in the 3d printed spacer.
This 3d printed spacer will join the Feather and CharliePlex board together.
This will allow a 350mAh lipo battery to safely sit between the two boards, with just enough space to fit the wires from both boards.
First fasten the two screws on the accelerometer mount. Leave the other two screws unfastened until we fit the battery cable through the opening on the spacer.
Next, we'll want to tidy up the wires by bundling them up with a small pieces of kapton tape. This will make it easier to arrange the wires allowing the battery to fit between the boards.
Now we can pass the battery wire through the opening on the side of the 3d printed spacer.
Reference the picture so the wires wraps around the board with enough space to plug into the Feather board.
Now we can fasten the other two M2x8mm screws through the Feather board. Tighten them in from the top of the Feather, into the spacer.
The Feather board should now be firmly attached to the 3d printed spacer. The CharliePlex board will attach after we mount it into the enclosure.
Plug in battery
First we'll need to plug in the battery before we insert it into the enclosure.
Reference the picture to route the wire along the side of the spacer, to the JST PH-2 connector on the Feather board.
If the LEDs light up, use the slide switch to turn the circuit off.
Mount inside enclosure
Align the CharliePlex to the enclosure, making sure the display cutout matches the LED matrix. (We're showing the box enclosure, but all of the design variants mount the same).
One side of the enclosure is wider to accommodate the JST connection on the side of the Feather board. Carefully fit the wires inside the enclosure. You can use tweezers to arrange them next to the spacer.
Align mounting holes
Flip the enclosure to the display cutout. Move the CharliePlex board so it aligns with the mounting holes on the front face of the enclosure.
Use four M2x8mm screws on the front face of the enclosure to attach the CharliePlex to the spacer.
To hide the screws on the front of the enclosure, we used a small amount of tac to adhere one of the printed face cover.
Slide Switch Tolerances
To adjust for different printer tolerances and to ensure the slide switch tightly press fits into the enclosure, we might need to gently spread the two metal sides. This will help the slide switch snap fit into place on the printed part.
Slide Switch Mount
First, carefully flip the slide the switch into the middle position. This will make it easier to pass through the opening in the enclosure.
Now we can insert the slide switch into the mount. Tilt the slide switch at an angle and then press fit into place.
The lid press fits onto the enclosure by aligning the nubs on both parts. Insert the protruding nubs on the lid into its matching cavity on the enclosure.
To assemble the gimbal version of the enclosure, simply insert the points on the sides, one by one, at an angle.
Use by holding the outer ring close, but not over the points that attach them to each other ring. Gently move in an up and down motion to spin the center of the gimbal!
The boards are offset so the display can mount to the center of the enclosure. This make it unstable on a dome, making the "grains of sand" bounce in unexpected fun ways.
Simply push on the side close to the USB port to randomly spin the enclosure on a flat table.
This guide was first published on Jan 10, 2018. It was last updated on Jan 10, 2018.
This page (Assembly) was last updated on Oct 12, 2020.