Bypass clean before shorter-22

AirNote

A touchless musical instrument built around a fully integrated RP2040, VL53L1X distance sensor and MAX98357A speaker amplifier. One hand selects eleven pentatonic notes over two octaves. The design uses a four-layer PCB and factory assembly, with an external 8 ohm speaker.

Engineering prototype, rev 0.2. The first-article order package has passed static review and is ready to order; nothing is ordered or physically validated yet. Use the independent review status for current failures, passes and pending evidence. A schematic check or firmware build does not establish that the assembled instrument works.

Open the design

Open hardware/airnote.kicad_pro in KiCad 9.0.9 or newer. The project contains three schematic sheets and the PCB. Project libraries accompany the files. The generated schematic can also be read in hardware/outputs/airnote-schematic.pdf.

View the PCB render. Some parts, including the volume pot, mute switch and amplifier, have no installed 3D body model; the render shows their footprints. Use the BOM and assembly drawing for the fitted-part list, and verify mechanical dimensions from their drawings.

The BOM identifies exact components with their LCSC part numbers for JLCPCB assembly. The fabricator, stackup and USB geometry are recorded in the fabrication plan; stock and prices are a snapshot and must be re-checked on the day of ordering. Manufacturing outputs remain engineering review artifacts until the independent review of the current revision passes.

Try the sound

Listen to the synthesized scale. This WAV is rendered by the same software oscillator used in firmware; it is not a recording of the PCB, amplifier or speaker.

Build and verify

Run from this directory. Native behavioral tests need CMake and a C++17 compiler; the device build additionally needs arm-none-eabi-gcc, Python 3 and Git. KiCad's Python module is used by the hardware tools.

cmake -S . -B build/host
cmake --build build/host -j 4
ctest --test-dir build/host --output-on-failure

python3 tools/fetch_dependencies.py
cmake -S firmware -B build/firmware
cmake --build build/firmware -j 8

The firmware build produces build/firmware/airnote.uf2 and airnote.elf. The captured build is also available as artifacts/airnote.uf2, with source and binary checksums in artifacts/firmware-evidence.json. The SDK may fetch/build its own picotool utility on the first build. Runtime dependencies are pinned in tools/fetch_dependencies.py; the vendored sensor and audio transport adaptations retain their licenses and provenance.

To regenerate the software sound preview:

build/host/render_demo artifacts/synth-preview.wav

Independent reviewer tests and artifact checks live in reviews/. The reviewer owns those checks separately from the implementation. Their result reports distinguish logic/net-mapping evidence from routing and physical tests.

Documents

• Requirements, targets and three-agent workflow
• Bring-up, programming, equipment and calibration procedure
• Power and thermal allocations
• Fabrication and sourcing plan (JLCPCB)
• Draft factory assembly brief
• Independent review checklist
• Current review status
• Exact part list
• Firmware pin assignment

Normal PLAY operation uses a specified 5 V adapter; programming/USB diagnostics use the hardware MUTE position. Firmware also latches a USB host mute, starts peripherals only after configuration or a deliberate adapter PLAY sequence, and parks audio after USB suspend/deconfiguration until power-cycle. These policies do not replace current/inrush/suspend measurements. The initial distance correction is zero and has not been calibrated to a physical board.

The overseer coordinates the specification and integration, the implementer creates the hardware, and the reviewer independently checks the artifacts and tests. Neither factory assembly nor clean ERC/DRC counts as physical validation.