Installation guide

Our home wall runs 5 V WS2812B LEDs, with a Raspberry Pi server and an ESP32 for Bluetooth. The first gym wall, at Bro Boulder, goes up in late 2026 with 12 V WS2811 pixel strings and an ESP32-S3. This guide follows the Bro Boulder design: 12 V pixel strings in 12 mm holes, a fused 12 V supply, and a controller that phones talk to over Bluetooth. Start with the Wall Planner for your layout and a parts list.

Intermediate
Our LED hardware is still in testing, so details here may change. If you plan to build a wall now, get in touch first.
Mains: wiring to mains (230 V/120 V) should be done by a qualified person. Everything after the supply runs on 12 V, but a 12 V supply can still deliver tens of amps. A short circuit can melt cables and start a fire, so every output needs a fuse and the right cable.

1. Drilling the panels

The LEDs are 12 mm bullet nodes in 12 mm holes through the plywood. Each node is pushed into its hole from behind and shines out through the front of the wall.

The grid

The holes go on a grid, 10, 15 or 20 cm apart. Bro Boulder uses 15 cm. Where the LED sits relative to the hold (under, above or in it) decides where you drill; see section 2. The planner lines the grid up so the joists and blocking fall between two rows of holes.

String spacing

Strings come with different spacing between nodes; 10, 15 and 20 cm are common, and any spacing works. Where the next hole is further away than the wire reaches, skip a pixel and leave it unused behind the wall.

2. Where the LED sits

An LED can sit under the hold, above it, or in the middle of it. Under and above are quick. Centred looks best but takes the most work.

A. Under or above the hold

The LED gets its own hole in the panel, below or above the hold. All the drilling is in wood. The hold must not cover the LED, so this needs some space beside every hold.

Quickest to build

B. Centred in the hold

A fibre rod is fitted in a hole drilled through the hold, and the light comes out on the hold itself. We use 12 mm rod for most holds and 6 mm for small holds and footholds; any size works. This looks best and allows the densest hold layout, since no LED needs room beside the hold. It takes time: every hold has to be drilled, and drilling through the plastic of a hold is harder than drilling through wood.

3. Routing the strings

The strings run up and down behind the panels, one node per hole. Each string has 50 nodes and plugs into the next one. A wall can use several parallel data lines: Bro Boulder is planned with three, driven by one 74AHCT125. The planner's plan uses one. The Wall Planner shows the route for your wall.

The route

  • - Between two joists: up one column of holes, down the next
  • - Then over the joist to the next space, and on across the wall
  • - Where the string goes over a joist or blocking, skip pixels. They stay unused behind the wall, and the app never lights them for a problem
  • - Nodes are numbered along the chain, from the controller end

Before you close the wall

Clip the wire to the back of the panel. Take photos of the wiring before you close the wall.

4. Power and wiring

The Wall Planner works out the supply size, the number of power taps, fuses and cable sizes for your wall. This section covers the physical work.

Power taps

A long chain dims towards the end, so 12 V and GND are fed in at several points. The planner puts a tap at the joint between every second string, so each tap feeds one string in each direction. Bro Boulder is planned with 8 taps for about 1 470 nodes. Lever connectors (Wago 221 or similar) at the joint are enough; no soldering.

Supply and fuse block

A 12 V supply feeds a blade fuse block with a GND bus. Every tap gets its own fuse and its own cable from the block, and the supply output gets a fuse too. Mount the supply and the fuse block together in a ventilated enclosure, out of reach of children.

Fuses and cable

The planner sizes each cable for the fuse in front of it and for a small voltage drop. Its sizes are for copper; CCA (copper-clad aluminium) cable needs a larger size. The planner assumes 0.6 W per node at full white (strings are sold as 0.3 or 0.6 W).

Safety

  • ! Mains (230 V/120 V) wiring should be done by a qualified person
  • ! Every tap gets its own fuse, never a cable straight from the supply
  • ! Never feed 12 V into the controller board
  • ! Supply, controller and LEDs share one GND

5. The controller

An ESP32 board drives the LEDs. Phones connect to it directly over Bluetooth, so the lights need no server, no internet and no gym WiFi. The firmware drives up to 2,000 nodes, and up to four phones can be connected at once.

Wiring

  • D GPIO 18 → 74AHCT125 level shifter → 22–47 Ω resistor → data input of the first node. The level shifter is optional, and recommended for long data lines; our home wall runs without one. If you use it, power it from the 5 V regulator.
  • G GND → the GND bus on the fuse block
  • P 12 V through a 12 V → 5 V regulator to the board's 5 V pin
  • C A 1000 µF capacitor, 16 V or more, across + and GND at the start of each data line

Keep the data wire from the controller to the first node short, under 5 m.

Firmware

The controller firmware is not published. If you want to build a wall now, get in touch.

6. Testing and mapping

Connect the app and tell it which node sits at which hold.

Connect and test

  1. 1. Power on the supply. The first LEDs flash green, then a blue light chases along the chain.
  2. 2. In the app, open the wall's settings, choose Bluetooth and pick your controller (see the app guide)
  3. 3. Light a few problems and check that every node works
  4. 4. Wrong colours point to the controller's colour-order setting (RGB or GRB)

Hold mapping

  1. 1. Upload a photo of your wall in the app
  2. 2. Mark each hold on the photo
  3. 3. Give each hold the number of the node behind it

Plan your wall

The Wall Planner works out the node count, power taps, cable sizes and a parts list.

Open the Wall Planner