Awesome

PouetPouet

The firmware is Keyberon, a pure rust firmware.

The goal was:

• build a custom keyboard from scratch
• continue to learn embedded rust
• have fun

Features

• ortholinear
• 60 keys, using Cherry MX switches, only 1U keycaps;
• 4 RGB LEDs for status;
• 6 RGB LEDs for backlight;
• USB-C connector;
• 1 STM32F072 MCU, with hardware USB DFU bootloader;
• Only onboard SMD component (except for the switches).
• ESD protection

Inspiration

• Keyseebee for being the «I will change it quickly and have something ready in an hour» base project (even if I ended up redoing most of the hardware design). It was really nice to have a solid base to learn and bootstrap the project.
• Typematrix 2030: I own 2 of them and really love them. But both are getting old and some keys are not working correctly (this motivated the keyboard change).
• Steamvan for some KiCad design ideas;
• Preonic as a model: ortholinear, good balance between size/usability, simple.

Usefull resources

• Mechanical Keyboard is a list of DIY keyboards
• Awesome Mechanical Keyboard is another «awesome» list
• Masterzen and many others for writing online tutorials for newbies like me.

Build log

Disclaimer: I'm a software developper, this is my first real PCB design and my first try at SMD soldering: do not take anything here for granted :)

The project started as a quick-hack of Keyseebee to make it simpler but ended up as a near full redesign. As every DIY project, the goal was to be quick and simple (spoiler: it was neither).

Half of the parts have been soldered with a soldering iron (TS80P), the other half with hot air station. Clearly, with my [un]existing soldering skills, the hot air is a huge win. But I think I would have simply spent more time by only using the iron. Even the small sod-323 diodes without the _handsoldering pads (mistake) were not a real problem (tricky, but even I could do it). For reference, I have soldered all SMD components for the second board under 2 hours with hot air.

The trickiest part is the USB connector if you don't have a hot air station: the plastic casing melts with the solder.

• The LEDs are mostly optional, and the 6 used for the backlight are nearly useless. I did not really study how to insert LEDs for a nice backlight and the result is not really satisfactory.
• I'll hopefully find time to use plexiglass plate to put below the PCB and above the visible part. I've added holes for this but never really planed anything really. If you really want something nice here, you may check this before.

Layout

As a typematrix user, I really like the middle column with backspace/enter/del so naturaly I've tried to do something similar. The initial layout has only the % and w key at different locations:

You can also see how the LEDs are currently used. It's mostly useless/for fun. They may be used someday to measure typing speed or do something else, but in the meantime, they blink like this: <img src="images/useless-leds.gif"/>

Bill Of Materials

The total for 3 keyboard is 71.25€. Beware that some parts can't be ordered for the exact amount and you need to buy more (in particular, aisler won't do anything under 3 units, so you need to spend at least ~90€ for 3 PCBs).

*: Bought using magic match from Aisler. Some components are then «free» (resistor, capacitor) and some are not.

Compiling and flashing

Install the complete toolchain and utils:

curl https://sh.rustup.rs -sSf | sh
rustup target add thumbv6m-none-eabi
rustup component add llvm-tools-preview
cargo install cargo-binutils
sudo apt-get install dfu-util

Compile:

Do not omit the --release as the debug code will not fit in the memory (the linker will raise an error).

cd firmware
cargo objcopy --bin pouetpouet --release -- -O binary pouetpouet.bin

To flash using dfu-util, first put the board in dfu mode by pressing BOOT, pressing and releasing RESET and releasing BOOT. Then:

dfu-util -d 0483:df11 -a 0 -s 0x08000000:leave -D pouetpouet.bin

The fist time, if the write fail, your flash might be protected. To unprotect:

dfu-util -d 0483:df11 -a 0 -s 0x08000000:force:unprotect -D pouetpouet.bin