Completed this project a few years ago, it was one of the first major builds I did with my 32x32. I had done several smaller projects before, but saw a similar coffee table on youtube and thought, I could figure that out. It’s a custom computer desk with a Wacom drawing tablet in the center, with an entire computer built into the interior, which is why its thicker at the back. I included cutouts for cables, power, USB ports, and the monitor. Unfortunately, I didn’t get any photos with the computer installed. It is sapele with black walnut trim around the outside and around the tablet. I finished it with Rubio Monocoat. I think I cover the basics, but am happy to answer any questions anyone might have.
For the CNC process, it was fairly straightforward:
- Cut the pattern: I created a repeating pentagon pattern that radiates from a center point where the display sits. I cut one half, rotated it 180°, and cut the other half. I put ALIGN in big letters in the center, where the display cut out was going to be, and had it cut that first so I could make sure everything was lined up. Also I screwed the desk down to a sheet of melamine to keep it supported off the edge of the table. This really helped keep everything secure as I moved it in and out of the garage. Most of thee assembly was done on the kitchen table. LOL
- Fill with epoxy: After the cuts, I filled the pattern with colored epoxy.
- Flatten: Once the epoxy dried, I used a surfacing bit to flatten the surface, completing the top surface.
- Recess for touch sensors: I flipped the desk over and cut out recesses in the center of each pentagon for the PCBs. It was a trick to get everything lined up. Ended up overcutting the recess just to make sure all the wood was removed from the epoxy, so the light would shine through. I also carved out a path for the sensor wire, leaving about 0.125-.25" of wood in the recess(I forget exactly what it ended up being)
- Circuit board design: Each PCB included LEDs and a capacitive touch sensor along with circuitry for a fade-out effect and some safety features. I used side-emitting LEDs, which shine light sideways in relation to how they are mounted to the board. Shining the light sideways into the epoxy creates a diffused effect when viewed from above, avoiding visible individual LEDs. The touch sensor functions similarly to a touchscreen, registering changes in the electrical field when a conductive object (like your hand) comes near. Through testing, I found that an additional conductor with a larger surface area was needed (the red wire in the pictures) to ensure the touch sensor would work through the wood, about 1/8" thick. Now, it registers my hand from about 1/4 to 1/2 inch above the desk. Although I tinkered with a basic prototype, I ultimately had someone else design the circuitry and Gerber files for the PCB. I found him on Fiver, he was amazing.
- Assembly: I fit the touchpad wires snugly into the recesses and used hot glue on the backs of the board for extra security. Custom wires were made to connect the boards, grouped into sets of six. Each group was wired together and connected to a switch at the back of the desk, allowing me to turn the lighting system on or off as needed. This way, the desk doesn’t light up unless I want it to.
- PC installation: After that, I installed all the PC components. The desk has a bottom panel with ventilation for the computer and is mounted on adjustable sit/stand legs.
- Power: I forgot power. Since I was installing a PC into the desk, I ended up siphoning 12V from the PC’s power supply accessory outputs to run the lights. Originally, I planned to use a separate 12V power supply but couldn’t find one that worked well enough(without spending $$$). The LEDs ended up being finicky and needed a relatively clean power source, and the cheaper supplies from Amazon I tried didn’t convert AC to DC reliably, causing flickering and inconsistent behavior. Sometimes the lights wouldn’t come on, sometimes they would, or they would stay on unexpectedly. I thought the project might be a loss until I realized it was just a crappy power brick. Then I used the PC power supply, which because it was designed for a computer was a lot higher quality. I created a custom wire harness to plug into it, connected everything, and it worked perfectly.
Cutting out the Pattern for the epoxy. Left room around the edge so I could screw it down. Also so the epoxy wouldn’t run out, then trimmed it later with a track saw.
After the epoxy was pored.
After it was surfaced.
Spritzed with water to see what it would look like.
Cutting out the recess for the PCBs and wire.
Close up of the cut out
Very basic proof of concept test board
Finished board. My circuit designer, really outdid himself.
Back of the board. They had built in touch pads but they were not effective enough so i added a big ole hunk a wire to make them more sensitive.
I used EasyEDA to manufacture my boards. From China to east coast US, I order 5 test boards that came in 4 days! I was completely blown away. Ultimately had them ship me 81 boards, 9 sets of 9, and that took a couple of weeks. This was the first time I did anything like this, and I still can’t
believe how fast it was.
This is what the final underside looked like. I put a sheet of 1/8th mdf over this and that is what I mounted my PC components to
