LapCounter CURRENT build 0.2 / optical gate / October 17, 2026

Open index.html or firmware/build-guide.html.
Downloadable source and flash files: LapCounter-firmware-0.2.zip.

Current design: one modulated IR emitter, one receiver gate that stores laps,
and one wearable display/haptic receiver. One runner on a controlled lane.
The optical gate decides crossings. Bluetooth repeats the absolute stored count.
It cannot identify people, determine direction or verify a full circuit.

CURRENT COST, USD
Parts, generic cases and mounts: $142.05
Shipping allowance: $20.00
Estimated 9% sales tax: $14.58
Subtotal: $176.63
20% contingency: $35.33
Total planning budget: $211.96
No contractor firmware labor budget. You still assemble and physically test it.
Existing tools/computer are assumed; hired assembly would be extra.

STATUS
Three real board-target firmware builds and UF2 flash files are supplied.
22 native cases pass, plus 5 export integrity cases. Software stress includes
100 synthetic 8-lap runs with dropped packets and 100,000 malformed payloads.
These tests do not establish optical performance or real-world lap reliability.
No target hardware is connected. Nothing has been flashed, assembled or field-tested.

Read firmware/BUILD-GUIDE.md before buying. Start with $37.60 of boards/optics
and reused USB supplies/cables to prove the optical link before the full kit.
The full guide has exact pin wiring, flashing, operation, logs and physical tests.

The 0.1 concept files and contractor-led report are retained as history, not the
current recommendation. Open concept-0.1.html to see the earlier interaction demo.
The old PDF and old parts spreadsheet do not describe this optical build.
