Candidate srj

flexisette

A flex-PCB cassette-tape multimedia object — a parametric, cassette-shaped board that plays its own music with a tiny animated display where the tape window would be. Designed as reproducible "drops": the whole thing regenerates from source (CAD, PCB, renders, firmware).

Status: work in progress. The mechanical CAD and the PCB design are functional and fabbable; the on-device firmware is early.

The idea

It's the size and shape of a compact cassette. A 0.96″ OLED sits behind the cassette's central tape window and plays a looping tape-winding animation — the one spot on a cassette where you expect to see motion. An ESP32-S3 plays the baked-in audio out a small speaker; it charges over USB-C and runs off a LiPo.

All parts are JLCPCB/LCSC-stocked for turnkey assembly.

Repository layout

cad/        parametric CAD (build123d) of the physical parts — frame, panel, insert, spacer —
            extracted from real vendor cassette STLs; mate-based assembly + MuJoCo sim
pcb/        the electronics PCB, code-driven with tscircuit (modules/ -> index.circuit.tsx),
            finished in KiCad. Includes the encoded place->route->measure tooling (scripts/)
            and per-fab DRC rule files (rules/)
display/    the 128x64 tape-winding animation for the OLED (display/tape_anim.py)
render/     Blender product renders / .blend files
assets/     vendor cassette shell STLs the CAD is derived from (see assets/DOWNLOADS.md for sources)
specs/      design specs
PARTS.md    component sourcing / BOM notes

Building

• CAD: make (or run the cad/*.py build123d scripts) → STL/STEP/FCStd in cad/build/.
• PCB: in pcb/, npm install then make build (tscircuit) → index.circuit.kicad_pcb; place with make outline / make routecheck, route with Freerouting (make freeroute) or in KiCad, and apply a fab rule set from pcb/rules/. The board outline is the real cassette face (derived from the same profile as the CAD).
• Animation: python3 display/tape_anim.py → a 128×64 GIF preview.

The PCB workflow follows the code-driven, placement-first approach (modular subcircuits, deterministic placement, ground pours, then route) — see docs/pcb-toolchain.md and docs/workflows.md.

Documentation

Full documentation lives in docs/ — start with docs/architecture.md for the big picture, then:

• PCB toolchain · Placement (the fast loop) · CAD enclosure
• 3D fit-check + renders · Fabrication (JLCPCB)
• Workflows — task recipes · Reference — every target/script/artifact
• Roadmap & known issues · Planned placement constraints

Project started June 25, 2026.

License

TBD. Vendor cassette assets under assets/ retain their original licenses — see assets/DOWNLOADS.md for attribution.