kmk_firmware/docs/pimoroni_trackball.md

Pimoroni Trackball

Module handles usage of Trackball Breakout by Pimoroni.

Product page: https://shop.pimoroni.com/products/trackball-breakout

Usage

Declare I2C bus and add this module in your main class.

from kmk.modules.pimoroni_trackball import Trackball, TrackballMode
import busio as io

i2c = io.I2C(scl=board.D3, sda=board.D2)
trackball = Trackball(i2c, mode=TrackballMode.MOUSE_MODE)
keyboard.modules.append(trackball)

Module will also work when you cannot use busio and do import bitbangio as io instead.

Key inputs

If you have used this thing on a mobile device, you will know it excels at cursor movement. You can get the same for any of your Layer:

trackball = Trackball(i2c, mode=TrackballMode.MOUSE_MODE, layers=[
    # act like an encoder, input arrow keys
    KeyLayer(KC.UP, KC.RIGHT, KC.DOWN, KC.LEFT, KC.ENTER), 
    # on layer 1 and above use the default pointing behavior
    PointingLayer()
])

Backlight

Setup backlight color using below commands:

trackball.set_rgbw(r, g, b, w)
trackball.set_red(brightness)
trackball.set_green(brightness)
trackball.set_blue(brightness)
trackball.set_white(brightness)

This module exposes one keycode TB_MODE, which on hold switches between MOUSE_MODE and SCROLL_MODE. To choose the default mode, pass it in Trackball constructor.