1x4 Macropad With Encoder

This is a build of a 1x4 Macropad with an ecoder using a Arduino Pro Micro and QMK Firmware

Table of contents

• Wiring
• Build
• QMK Firmware
• Compile And Flash

Wiring

I wired this in the COL2ROW diode configuration. How this works is each column is connected to its own pin then the other side of the switch is connected to a diode with the line on the far side. The other side of the diode is connected to the ends of all the other diodes in the same row.

The rotary encoder has 5 pins. The two on one side are a switch that is activated by pressing in the dial like a R3 on a game controller. The other side with 3 pins are connected to pins on the arduino with the middle pin connected to ground.

Build

I didn't put much thought into the design or build. There are 4 parts. They are held together by 4 M3x20mm screws and 8 M3 nuts. Install everything on the top plate and wire. Match the face plate with the base and cut the wires to size. Solder up the pro-micro and test. To get the M3 nuts to sit apply a soldering tip to them and melt them into the hole.

QMK Firmware

In the config.h file we set the pins on the pro-micro. Note they are not the same pins printed on the board. You can find the pin lables here https://deskthority.net/wiki/Arduino_Pro_Micro. DIODE_DIRECTION is importand to note.

/* key matrix size */
#define MATRIX_ROWS 1
#define MATRIX_COLS 5

/* key matrix pins */
#define MATRIX_ROW_PINS { F7 }
#define MATRIX_COL_PINS { B3, B4, B1, B2, B5 }
#define UNUSED_PINS

#define ENCODERS_PAD_A { D1 }
#define ENCODERS_PAD_B { E6 }
#define ENCODER_DIRECTION_FLIP

/* COL2ROW or ROW2COL */
#define DIODE_DIRECTION COL2ROW

/* number of backlight levels */

In the kb/keymaps/default/keymap.c you can change the key bindings. Currently I have them set to

• LCTL(KC_Z) Undo
• LCTL(KC_C) Copy
• LCTL(KC_V) Paste
• LCTL(LSFT(KC_M)) Mute mic in MS Teams
• KC_MUTE Rotary encoder push button mutes speakers

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {

	KEYMAP(
		LCTL(KC_Z), LCTL(KC_C), LCTL(KC_V), LCTL(LSFT(KC_M)), KC_MUTE),
}

The rotary encoder is mapped in the keymap.c file with

• KC_AUDIO_VOL_UP and KC_AUDIO_VOL_DOWN Turns the volume up and down

void encoder_update_user(int8_t index, bool clockwise) {
    if (clockwise) {
      tap_code(KC_AUDIO_VOL_UP);
    } else {
      tap_code(KC_AUDIO_VOL_DOWN);
    }
}

Compile And Flash

• First install QMK and QMK Toolbox

To compile move the files into your qmk directory under keyboards like this.

load up your MSYS2 MinGW 64-bit where qmk is installed and run

$ qmk compile -kb kb -km default

It should look like this

One complete under the /qmk-firmware/ will be a kb_default.hex

Load up QMK Toolbox. Click open and choose the /qmk_firmware/kb_default.hex. Click autoflash. Connect your pro-micro via usb. To enter bootloader mode short the reset and ground pins. QMK Toolbox will auto detect it and flash it. It should look like this.