absonus — Ribbon Synthesizer

A touch-controlled FM ribbon synthesizer built on the Electrosmith Daisy Seed platform. Pitch is controlled by a 150mm soft-pot ribbon sensor; expression by a force-sensitive resistor. A panel of knobs and switches shapes the FM synthesis, distortion, filter, tremolo, and reverb.

Repository Structure

absonus/
├── firmware/
│   ├── absonus/          Main firmware (DaisyDuino sketch)
│   └── sensor-test/      Utility sketch — reads all panel inputs over serial
│
├── hardware/
│   ├── enclosure/        FreeCAD / DXF / STL files for the enclosure and drill templates
│   ├── pcb/
│   │   ├── absonus-v0.2/ KiCad schematic and PCB layout (current)
│   │   ├── battery-clamp/ 3D-printable clamp for the 18650 battery holder
│   │   └── library/      KiCad component libraries (symbols + footprints)
│   └── testing-panel/    Laser-cut test panel drawings
│
├── bom/
│   ├── pcb-assembly-bom.csv    JLCPCB assembly BOM for the main PCB
│   └── sourced-components.md   Hand-sourced components (pots, sensors, enclosure, etc.)
│
├── docs/
│   ├── design-notes.md         Hardware layout and component design notes
│   ├── firmware-architecture.md Signal chain, module reference, pin mapping
│   └── datasheets/             Component datasheets (FSR, SoftPot, LS18-P, etc.)
│
├── assets/               Photos, renders (to be added)
│
└── archive/
    ├── firmware/         Earlier prototype sketches (fm, fm-chorus, tremor, sensor-test)
    └── hardware/         Earlier PCB revisions (pcb-v0.1, lipo-charger-booster, power-supply)

Documentation

• Firmware Architecture — signal chain, DSP modules, pin mapping, portamento times
• Design Notes — panel layout, Daisy Seed pin assignments, component selection notes
• Sourced Components BOM — hand-sourced parts with supplier links
• PCB Assembly BOM — JLCPCB SMT assembly BOM for the main board

Build

Open firmware/absonus/absonus.ino in Arduino IDE with the DaisyDuino board package installed. Select Daisy Seed as the target board.

Hardware Verification

Before troubleshooting from audio output, flash firmware/sensor-test/sensor-test.ino to the Daisy Seed immediately after assembly. It reads every pot, switch, force sensor, and soft-pot and streams their normalized values over serial (9600 baud, 100 ms interval). Use the Arduino Serial Plotter or any serial monitor to confirm each input responds correctly and is wired to the right pin before loading the main firmware.