This guide assumes you have some keyboard soldering experience. There are multiple ways to build the Sofle RGB Keyboard v2.1. Here is a build with 72 RGB LEDs, two rotary encoders, and two OLED display modules.
Flash the Firmware
Flash the two Pro Micro Controllers or USB Type-C Controllers with QMK ToolBox.
The Front side is for the pro micro controller boards, OLED display modules, TRRS jacks, reset buttons, rotary encoders.
The Back side is for the diodes and Kailh MX switch hotswap sockets.
There are RGB LEDs on both sides.
Bridge the Solder Pads for OLED Display Modules
On the Front Side, bridge the 4 solder pads on left hand PCB and right hand PCB.
Solder the Diodes
Flip to the Back side, solder all the diodes on both sides. Diodes are directional.
A common mistake is, we miss the diode near the rotary encoder.
do not bridge the solder pads on the back
The OLED solder pads should NOT be bridged on the Back side.
All the diodes are soldered.
Microcontroller Breakout Board
USB Type-C (ShiroC)
Align the two controllers according to the silkscreen outline. The boards should be mounted with the components facing down.
The same applies to a generic pro micro controller board.
For Either Controller Boards
The back side should look like this.
Testing the Keyboard
You now have a minimally working, single-sided keyboard.
If you connect the left side, or the right side to the computer, and short the hotswap solder pads (front or back), you should be able to enter some keys.
Kailh Hotswap Sockets
Solder the hotswap socket according to the silkscreen. A common mistake is to mount it 180 degree rotated.
Make sure the sockets stay flat.
Solder the rest of the sockets.
TRRS Jack and Reset Button
If you plan to add the RGB LEDs, you should skip this step and move this to the last.
RGB LEDs for the Right Hand
Bridge "IND", "UND&BL", and "ENA" on the back side.