Hexagon LED coffee table

Introduction

I saw a short tiktok with a led table that lights up when touched and immediately felt like building it myself. 

For the hexagons I have also designed suitable circuit boards, so that these are also nicely illuminated. In total I have made 61 individual fields, each with 6 LEDs and a touch sensor. As touch sensors i used ttp223, i scraped some varnish off the board and soldered on a wire.
To test whether this works at all with the printed parts and the shine through, I have cast me a small plate with 7 fields. 

The whole thing has a very high power consumption, if all fields are on and white at the same time.

PCBs

Since the pcb files unfortunately can't be uploaded here, I'll upload the whole thing to Github and then link it. With the files i ordered everything from jlcpcb. Actually the main-pcb should be as smd, but the parts were not in stock, so now it became a normal one. 

The main-pcb has 4x MCP23017, 1x 1500uF Capacitor, 1x Fuse holder, 1x SN74HC125N and 1x ESP32 Dev Kit C

mazls/hexagon-desk: Epoxy coffe table with 3d printed hexagon inserts and led pcbs with touch sensor (github.com)

Build

So that the hexagon parts always have the same distance to each other, I have made small spacers to insert.

The hexagons are printed in two colors. The top in Prusament Galaxy Black and the rest in Prusament Clear. The parts can be printed either in mmu or with a manual color change. The inner ring is only to shield the red led from the touch sensors so that it does not shine through. The outer walls are just 0.8mm thick so the normal LEDs of the hexagons are still visible throug the epoxy.

I first poured a layer of clear epoxy resin into the cut-out wooden plate and let it harden. Then clear epoxy resin again and the hexagons brushed with epoxy and inserted. I aligned the hexagons with the spacers and let the whole thing cure. Then I removed the spacers and poured in the resin mixed with powder. I used about 4 kg of epoxy resin for the table.

I used release tape to get the epoxy off the base. You have to work precisely here, otherwise you will have a lot of sanding work later. Therefore, the first layer of clear epoxy resin. This gives you some leeway and allows you to sand again.

With the wooden plates I had some problems with the procurement, therefore it became 3 plates. The first with 27mm, in it are the hexagons with the resin, then one with 18mm and then another with 18mm. The first two plates (27mm and 18mm) have the same inner cutout for the wiring. The last 18mm plate is for covering and fixing the table legs. I made the whole thing with metric wood inserts so I can disassemble the tabletop again if there is a problem with the leds or the sensors.

For the sake of completeness i have attached the plan of my table legs. I got them cut in the local hardware store and glued it together.

For the final finish i applied some hard oil to the wood.

BOM

• 1x 120x60x2.6cm beech glue laminated panel
• 2x 120x60x1.8cm beech glue laminated panel
• 4kg epoxy resin (i ordered 4.5kg)
• metallic pulver for epoxy
• 61x hexagon pcbs
• 61x printed hexagons
• 61x TTP223 touch sensor
• lot of wire, i used 0.5mm² for all hexagons
• 1x main pcb
  • 4x MCP23017
  • 1x 1500uF Capacitor
  • 1x Fuse holder
  • 1x SN74HC125N
  • 1x ESP32 Dev Kit C
• 1x DC Hollow Plug 5.5 x 2.1MM
• screws to connect the plates
• wood glue
• 26x 400x90x18mm beech glue laminated panels for the legs
• 5v power supply (i choose 8A, that was the max i can get)
• Fuse for the main pcb
• inserts for wood, just when you want the plate to be detachable for fixing the touch sensors or replacing a pcb etc.