Trackside
A desk mixer for per-app volume
Trackside is a USB desk mixer that gives Windows programs physical faders. Four 60 mm faders, three keys and a 2.79" bar display sit beside the keyboard. Each fader controls one program (Discord, Spotify, a game, the program in front) or the master volume. Banks switch the faders between sets of programs with one key.
The fader caps are dice, so the pips tell you which channel is which.
Hardware
- Custom PCB designed in KiCad, assembled by JLCPCB
- ESP32-S3
- 16-bit ADC for the faders
- Low-profile hot-swap keys
- Addressable RGB lighting
- Enclosure
- Modelled parametrically in Fusion 360 and 3D printed.
- Firmware
- Tile-based screen rendering with cross-fades and a startup animation, a custom LED driver, a fader calibration wizard, and an app icon and colour for each fader on the display. Everything talks to the PC over a line-based USB protocol.
- Desktop app
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- A pixel-exact mirror of the device's screen, checked against the firmware's own drawing code compiled for desktop.
- A large view one click away to pin programs, adjust brightness and look up what each key does.
- A settings window for banks, keys and the device.
- Changes edit the settings file in place and keep the user's comments.
- In progress
- A media mode that turns the screen into a now-playing display with album art, and colour themes for the device.
- Process
- Every screen was mocked up and approved before it was built. About 3,800 automated tests cover the app, protocol and rendering.
- Built with
- KiCad, Fusion 360, ESP32-S3 (PlatformIO), Python (Tk, Pillow, pycaw, pywinrt)