Ever since I first saw the microwriter, I have been fascinated by chorded keyboards: single handed keyboards with a handful (literally) of keys where instead of pressing one key at a time, you press a "chord" (several keys) to select each letter.
Now that low cost Bluetooth LE devices like the Adafruit NRF52 are cheap and easy to program, there really was no excuse not to build one.
The keymap is based on the "modified NASA" keymap as described in the following tables.
| Keys | Thumb | |
|---|---|---|
| -RMI | -C- | a |
| P--I | --- | b |
| --M- | -C- | c |
| --MI | --- | d |
| -RMI | --- | e |
| P--- | -C- | f |
| -R-- | -C- | g |
| -RM- | --- | h |
| ---I | --- | i |
| -R-I | -C- | j |
| -R-I | --- | k |
| ---I | -C- | l |
| --MI | -C- | m |
| PRM- | -C- | n |
| PRMI | -C- | o |
| -RM- | -C- | p |
| PR-I | -C- | q |
| --M- | --- | r |
| PRM- | --- | s |
| PRMI | --- | t |
| PR-- | --- | u |
| PR-- | -C- | v |
| P--- | --- | w |
| P--I | -C- | x |
| -R-- | --- | y |
| PR-I | --- | z |
| ---- | -C- | spc |
| Keys | Thumb | ||
|---|---|---|---|
| PR-- | N-- | ; | : |
| --M- | N-- | , | < |
| -RM- | N-- | . | > |
| -RMI | N-- | ' | " |
| -R-- | N-- | esc | |
| PRM- | N-- | alt | |
| PR-I | N-- | ctrl | |
| P--- | N-- | fnc | |
| PRMI | N-- | numl | |
| P--I | N-- | ins | |
| ---- | NCF | qwerty | |
| ---- | N-F | dvorak |
| Keys | Thumb | F | hint | |
|---|---|---|---|---|
| ---- | -C- | 1 | ! | |
| ---I | --- | 2 | @ | |
| --M- | --- | 3 | # | |
| -R-- | --- | 4 | $ | |
| P--- | --- | 5 | % | |
| ---I | -C- | 6 | ^ | |
| --M- | -C- | 7 | * | |
| -R-- | -C- | 8 | * | |
| P--- | -C- | 9 | ( | |
| PRMI | -C- | 0 | ) | |
| -RMI | -C- | + | a | |
| P--I | --- | \ | | | b |
| --MI | --- | / | ? | d |
| -RMI | --- | = | + | e |
| -R-I | --- | $ | k | |
| --MI | -C- | * | m | |
| PRM- | -C- | [ | { | n |
| PR-- | -C- | ] | } | v |
| -RM- | -C- | % | p | |
| PR-I | -C- | ? | q | |
| PRM- | --- | - | _ | s |
| P--I | -C- | & | x | |
| PR-I | --- | ` | ~ | z |
| Keys | Thumb | F>CF | |
|---|---|---|---|
| PRMI | NC- | kpl | |
| P--- | --F | ret | kp ret |
| ---- | --F | lshf | kp + |
| PRMI | --F | caps | kp ins |
| -R-I | --F | tab | kp - |
| --M- | --F | bksp | kp beg |
| -RM- | --F | del | kp del |
| P-MI | --F | sclk | kp / |
| P-M- | --F | ptsc | kp * |
| -R-- | --F | rght | kp rght |
| PR-- | --F | down | kp down |
| PRM- | --F | pgdn | kp pgdn |
| ---I | --F | left | kp left |
| --MI | --F | up | kp up |
| -RMI | --F | pgup | kp pgup |
| PR-I | --F | home | kp home |
| P--I | --F | end | kp end |
| ---- | N-F | brk | |
| ---- | NCF | rst |
Install the tool and Adafruit library as follows
wget https://developer.arm.com/-/media/Files/downloads/gnu-rm/7-2017q4/gcc-arm-none-eabi-7-2017-q4-major-mac.tar.bz2
tar jxf gcc-arm-none-eabi-7-2017-q4-major-mac.tar.bz2
git submodule init
git submodule update
pushd Adafruit_nRF52_Arduino/tools/nrfutil-0.5.2
# to install the packages, you might need to disable virtualenv
# (or you might want to select an appropriate virtualenv)
export PIP_REQUIRE_VIRTUALENV=false
pip install --user -r requirements.txt
python setup.py install
popd
# download and install driver for CP2104 USB-to-Serial (the chip on the NRF52 board)
wget https://www.silabs.com/documents/public/software/Mac_OSX_VCP_Driver.zip
unzip Mac_OSX_VCP_Driver.zip
open SiLabsUSBDriverDisk.dmg
# install the driver
# confirm install (if NRF board is connected over USB at the moment)
ls /dev/*USB*
# Should show: /dev/cu.SLAB_USBtoUART /dev/tty.SLAB_USBtoUART
Build the Adafruit library as follows. This will generate a lot of warning messages --- hold your nose and ignore them.
make nrf52_cores.a
Build as follows
make main.elf
Upload as follows
make upload
You should be able to pair your phone or laptop with the keyer. Open up an editor and try typing some sentences.
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