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Keyboard Keyboard Side View

The Sofle Choc is a variation of the Sofle with:

This version supports Kailh Choc v1 switches. Kailh hotswap sockets are required. Per-key RGB is optional and uses the relativey easy to solder SK6812 MINI-E LEDs.

The top plates are not compatible with Sofle v1, v2 or RGB versions. There is no bottom plate to minimize thickness.

The Sofle Choc was designed by Brian Low and based on the excellent Sofle RGB by Dane Evans which was based on the original Sofle v2 by Josef Adamčík.

Updated Build Guide and Kits

I am maintaining a newer version of the build guide and usually have kits available at:

http://choc.brianlow.com

Bill of materials

The following is needed to build the keyboard:

Optional components:

Components that are common on other Sofle variants but are not used on this Softle Choc: bottom plate, M2 spacers and screws.

Tools and materials

Steps

Prepare

Make sure you know which side you are working on, and don’t make two left hand sides by mistake. Stick a piece of tape on the front side of both PCBs to help remember.

This guide is written in the order I like to install components.

We will start with the components on the back, shortest to tallest:

Then install the components on the front:

The order of assemby does not matter except for these 3 components because they stack on top of one another:

  1. the four OLED jumpers
  2. the Pro Micro
  3. the OLED screen

The build guides for the Sofle and Sofle RGB have some good tips and photos. However there are differences so use this page as your primary reference. In particular, use the ProMicro orientation described on this page.

Switch Sockets and Diodes

Switch sockets and diodes

These components are placed on the back of the PCB.

Diodes must be oriented with the white band in the direction of the “arrow” symbol on the PCB. I typically tin one pad, place the diode on, apply the soldering iron to the diode leg until it melts the solder underneath and sinks flush with the PCB. Then come back and solder the other leg.

The sockets are the largest and easiest to solder. They are installed on the back of the PCB facing up towards the front of the PCB. Make sure they are flush with the PCB. Heat the metal connector, apply solder and look for the solder to wick down to the PCB. You want a solid joint since this may take some mechanical strain from switch installation and removal.

The LEDs

LED

LEDs are placed on the back of the PCB. The lens should point up through the PCB so they shine into the bottom of the switch. One leg will have a diagonal cut. This cut leg should be aligned with the triangular marking on the PCB.

To solder: tin one pad, place the LED and hold using tweezers, apply heat to the leg until the solder melts and the LED is flush with the board. Now the remaining legs can be soldered without the component moving. The LEDs are sensitive to heat. Let the LED cool between soldering each leg. Use the lowest heat needed for your solder.

The LEDs are wired in one long chain. If a LED is not working, replace the LED and the LED preceeding it. Sometimes just the output of a LED is damaged. The full chain does not need to be installed if you want to test a partially built board.

LED

OLED Jumpers

OLED Jumpers

Now we move to the front of the PCB.

The jumpers in the photo should be bridged if using an OLED dispay. The jumpers may not be accessible later in the build depending on how the Pro Micro is attached. Bridge the jumpers on the top side of the board, the same side the ProMicro will be mounted on.

Pro Micro

Pro Micro

The Pro Micro is installed on the top of the board, upside down and in the marked holes.

Double-check your work here. This step is hard to reverse if a mistake is made.

To install a socketed Pro Micro using the diode leg approach from splitkb.com:

  1. Install the 12-pin female headers on the top of the board in the outlined through holes. Use some tape to temporarily tack them in place. Flip the board over onto a flat, hard surface. While soldering the first pins, push down on the PCB to ensure the headers are perpendicular and fully seated.

  2. Flip the board upright again. Optionally place some tape over the sockets to protect again fusing parts together. Place the Pro Micro upside down on top. Push diodes though the Pro Micro holes, through the tape and seated into the socket below.

  3. Solder the legs to the Pro Micro. Snip off the legs above the Pro Micro.

If you ever need to remove the Pro Micro: do it by gently prying the board up in small increments, working your way around the board. Avoid pressure on the USB connector. The diode leags are quite weak and will usually bend if you pull the Pro Micro off in one action.

OLED

Install the OLED so it overhangs the Pro Micro. I added electrican’s tape to the bottom of the OLED module where it might contact the Pro Micro.

If you are socketing the OLED, install the 4 pin, half height female header on the top of the PCB. Then push the OLED pins into the socket. You may need to trim the OLED pins so the insulation on the female and male headers mate and the OLED sits just above the Pro Micro. The downside to socketing is the OLED isn’t as secure in the half height socket. When turning the keyboard upside down I find the OLED will lever away from the Pro Micro somewhat.

Solder misc components

Use tape to tack each component in place while flipping the board over to solder.

Solder the reset switch.

Solder the TRRS connector. You may need to bend the TRRS connector pins 90 degrees so they point down into the PCB. The R1 and R2 locations should remain empty.

Solder the encoder.

Assemble

Warnings and disclaimers

Firmware and programming

The Sofle Choc uses QMK Firmware. Support is not in the main QMK repository yet. Instead use the brianlow/qmk_firmware fork.

Suggested approach is to build the firmware yourself. You should be familiar with QMK and be able to make it work on your local environment. If not, please follow the instructions in the documentation. Note QMK setup is fairly invasive (upgrade every homebrew package on your system) so you might want to consider the QMK Docker image for compiling.

To flash:

There is also a firmware version that uses VIA. VIA allows you to quickly change your keymap without flashing or a QMK build environment. I highly recommend it for experimenting. There are few downsides:

To use the VIA firmware

Troubleshooting

See the Sofle build guide.

Default layout

The default layout for the Sofle is in the qmk repo, and demonstrates some LED functions.

Default layout for SofleRGB Keyboard

Images of keyboard

Keyboard Photo 1

Keyboard Photo 2

Version History

Footnotes