shortcuts underfoot

Pedalboard turns three momentary foot switches into a wireless keyboard. It is built around a Seeed Studio XIAO nRF52840 and runs RMK, a keyboard firmware written in Rust.

Use it over Bluetooth or USB for push-to-talk, muting, automation, or any action that is useful while both hands are busy.

Controls

The default layout emits uncommon macOS shortcuts for automation tools to pick up. “Meh” means Control + Option + Shift.

Pedal	Tap	Hold for one second
Left	Meh + F16	—
Middle	Meh + F17	Mute audio output
Right	Meh + M	Meh + Backspace

Hold the left pedal while resetting or powering on the controller to enter the UF2 bootloader. While the firmware is running, press the left and right pedals together and hold both for 2 seconds to reboot the controller.

Hardware

Each normally-open switch connects one GPIO directly to ground; RMK supplies the pull-up resistor.

Pedal	XIAO nRF52840 GPIO
Left	P0.02
Middle	P0.03
Right	P0.28

There are no diodes or key matrix: three switches, three signal wires, and ground are enough.

Build and flash

Install Rust and cargo-make, then build the UF2 image:

cargo install --force cargo-make
just build

Hold the left pedal while resetting the XIAO. When the XIAO-SENSE drive appears, flash the firmware with:

just flash

The key bindings, pins, Bluetooth settings, and hold timing live in keyboard.toml.