QMK Firmware

How you upload the firmware to your Arduino, depends on your computer’s operating system. As I prefer to work with macOS, this guide uses tools and commands that work fine on a current High Sierra v10.13 machine.

USB Cable

You need a Micro-USB cable to connect the Arduino Pro Micro. The cable is required for uploading a new firmware and using the keyboard afterward. You can just order any ordinary cable from the Shopping List, or look for a vendor that makes awesome-looking custom cables.

Do you work for a company that offers custom USB cables and you can provide a discount code? I would love to feature your business and services here! Please let me know.

If you use the Shrink Kit, you can use already use the Mini-USB cable to flash the Arduino. The connection works for using the keyboard, as well as uploading a new firmware to it.

Dependencies

To flash your Arduino with software, and for compiling the firmware, you must install a few tools like avr-gcc and avrdude. Both are available on Homebrew, but I recommend the CrossPack by ObDev.

CrossPack for AVR

DMG, 42 MB

CrossPack for AVR Development is distributed under the terms of the GNU General Public License version 2, except AVR Libc which is distributed under a more liberal license. See the manual for the full text of these licenses.

Firmware

The firmware is based on QMK and customized to work with the Arduino Pro Micro on the board. All sources for the keyboard are available on GitHub using the GPL v2 license.

$ > git clone https://github.com/sbstjn/qmk_firmware.git
$ > cd qmk_firmware

The repository already includes a default keyboard configuration that you can use right away available in the keymap.c file. The file is located in the keyboards/68keys folder.

#include QMK_KEYBOARD_H
#include "68keys.h"

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
    [0] = LAYOUT_68_ansi(
        KC_GRV, KC_1, KC_2, KC_3, KC_4, KC_5, KC_6, KC_7, KC_8, KC_9, KC_0, KC_MINS, KC_EQL, KC_BSPC, KC_ESC, KC_PGUP,
        KC_TAB, KC_Q, KC_W, KC_E, KC_R, KC_T, KC_Y, KC_U, KC_I, KC_O, KC_P, KC_LBRC, KC_RBRC, KC_BSLS, KC_DEL, KC_PGDN,
        MO(1), KC_A, KC_S, KC_D, KC_F, KC_G, KC_H, KC_J, KC_K, KC_L, KC_SCLN, KC_QUOT, KC_ENT,
        KC_LSFT, KC_Z, KC_X, KC_C, KC_V, KC_B, KC_N, KC_M, KC_COMM, KC_DOT, KC_SLSH, KC_RSFT, KC_UP,
        KC_LCTL, KC_LALT, KC_LGUI, KC_SPC, KC_RGUI, KC_RALT, KC_RCTL, KC_LEFT, KC_DOWN, KC_RGHT),
    [1] = LAYOUT_68_ansi(
        KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
        KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
        MO(1), KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
        KC_TRNS, KC_TRNS, KC_MPLY, KC_MSTP, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_VOLU,
        KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_MPRV, KC_VOLD, KC_MNXT)
};

Basically, I only moved ESC to the right side. Thanks to QMK, you can easily add additional layers and replace Caps Lock for example with FN. Holding FN could enable a second keyboard layer, which includes media controls.

Compile your Firmware

After you have installed all needed dependencies, compile the firmware with your custom keyboard layout:

$ > make 68keys:default

[...]

Checking file size of 68keys_default.hex [OK]
 * The firmware size is fine - 14096/28672 (14576 bytes free)

When the command finishes without errors, you end up with a few 68Keys.* files in the .build folder. In the next step you will upload the firmware to your Arduino board.

Upload Firmware

Connect the Micro-USB cable to your Arduino Pro Micro and your computer. The board should be listed using ls /dev/tty.* . If you cannot find your board, first check if the green light on the Arduino is on.

$ > ls /dev/tty.*

crw-rw-rw-  1 root  wheel   21,   4 Jan 24 12:06 /dev/tty.Bluetooth-Incoming-Port
crw-rw-rw-  1 root  wheel   21,   2 Jan 24 12:06 /dev/tty.MALS
crw-rw-rw-  1 root  wheel   21,   0 Jan 24 12:06 /dev/tty.SOC
crw-rw-rw-  1 root  wheel   21,   0 Jan 24 12:06 /dev/tty.usbmodem1441

If your computer detected the Arduino board correctly, it’s time to upload your custom firmware to it.

$ > make 68keys:default:avrdude

On some systems, the number following usbmodem increases every time you re-connect the board. On others, it stays the same or just switches to a different number when the Bootloader is enabled. Just run ls /dev/tty.* after you connected the board or enabled the Bootloader to figure this out.

After you hit enter you will see a prompt to reset your controller. You can use the Push Button to enter the Bootload on your Arduino. Press it twice directly after re-connecting the board to your computer and the process to flash the firmware to the board will start automatically.

Checking file size of 68keys_default.hex                        [OK]
 * The firmware size is fine - 14096/28672 (14576 bytes free)
Copying 68keys_default.hex to qmk_firmware folder               [OK]
Detecting USB port, reset your controller now..............

Detected controller on USB port at /dev/tty.usbmodem146101

Reading | ################################################## | 100% 0.00s

avrdude: Device signature = 0x1e9587
avrdude: erasing chip
avrdude: reading input file ".build/68keys_default.hex"
avrdude: input file .build/68keys_default.hex auto detected as Intel Hex
avrdude: writing flash (14096 bytes):

Writing | ################################################## | 100% 1.06s

avrdude: 14096 bytes of flash written
avrdude: verifying flash memory against .build/68keys_default.hex:
avrdude: load data flash data from input file .build/68keys_default.hex:
avrdude: input file .build/68keys_default.hex auto detected as Intel Hex
avrdude: input file .build/68keys_default.hex contains 14096 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 0.12s

avrdude: verifying ...
avrdude: 14096 bytes of flash verified

avrdude: safemode: Fuses OK (H:CB, E:D8, L:FF)

avrdude done.  Thank you.

Make sure everything works

You can install lsusb using Homebrew to list all connected USB devices. If you uploaded the firmware to the Arduino, you computer should list the keyboard with its name.

$ > lsusb

Bus 020 Device 004: ID feed:0a0c feed  The 68Keys.io Keyboard
Bus 000 Device 001: ID 1d6b:ISPT Linux Foundation USB 3.0 Bus
Bus 001 Device 001: ID 1d6b:CIAR Linux Foundation USB 3.1 Bus
Bus 000 Device 001: ID 1d6b:CIAR Linux Foundation USB 3.1 Bus

Finish the Sandwich Case

After the successful upload of your firmware, you should finally be able to use the keyboard after re-connecting it to your computer. If everything works as expected, it’s time to close the Sandwich Case and you’re done!

Make sure the Micro-USB cable is connected to the Arduino board and use the M3 Screws and Standoffs to close the Sandwich Case.

Custom 68% Mechanical Keyboard from 68Keys.io

Thanks!

Woow, that was a ride! Thanks for reading this guide, I hope you enjoyed building your new mechanical keyboard. I would love to hear your feedback and see the results of your work, please share them on twitter. What key caps did you use for your keyboard? The SA Grade set is a perfect match! 😍

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