Ben Meadors b565a07a83 Remove proprietary Bosch BSEC blob; open in-tree IAQ estimator for BME680 (#11381) ...

* Remove proprietary Bosch BSEC blob; open in-tree IAQ estimator for BME680

BSEC2 cost ~37-39 KB flash and ~4-5 KB static RAM on ~190 of ~240 build
targets, linked whether or not a BME680 was attached, and was a no-source
proprietary archive inside GPLv3 release binaries. The firmware consumed
exactly one BSEC-exclusive output: the IAQ value.

- New BME680IaqEstimator: clean-room log-domain baseline tracker
  (humidity-compensated gas resistance vs a rise-fast/decay-slow ceiling,
  0-500 scale matching the existing UI bands), pure math, unit-tested on
  native (test_bme680_iaq, 15 tests incl. a deep-sleep reboot simulation).
  Warm-up/burn-in progress persists to /prefs/bme680.dat via SafeFile so
  one-sample-per-wake SENSOR nodes converge across reboots; stale
  /prefs/bsec.dat is removed once.
- BME680Sensor: single-path rewrite on Adafruit_BME680 with async
  once-per-minute sampling (~20x lower heater duty than BSEC LP mode),
  a hard 2-minute publish-freshness bound (a dead sensor stops reporting
  instead of freezing its last reading on the wire), and suppression of
  bogus gas_resistance=0 points from heater-unstable cycles.
- platformio.ini: environmental_extra_common/_extra/_no_bsec collapsed
  into one section; Bosch BSEC2 + BME68x deps deleted; per-variant BSEC
  link-path hacks and the TEMPORARY promicro lib_ignore removed.
  nrf52_promicro_diy_tcxo regains BME680 support at 36 KB clear of the
  warm-store cap; rak4631 lands at 75 KB clear.
- EnvironmentTelemetry: iaq rendering gates on has_iaq (a genuine IAQ of
  0 now displays); stale BSEC comments rewritten.
- rak4631 size budgets tightened (113000->108000 RAM, 786000->746000
  flash) to lock in the reclaimed headroom.
- bin/bme680_iaq_replay.cpp: host-side replay harness for tuning the
  estimator against captured BSEC traces (mean abs error + band
  agreement), no reflashing needed.

Measured (develop -> this branch): rak4631 -38.8 KB flash / -4.9 KB RAM;
heltec-v3 -36.4 KB / -4.0 KB; tlora-v2-1-1_6 +1.3 KB (its IAQ
approximation had been dead code since #9663 due to an inverted isfinite
check and now actually runs).

Note: gas_resistance stays kOhm on the wire for fleet compatibility; the
proto comment claiming MOhm gets a separate meshtastic/protobufs docs PR.

* Address CodeRabbit review feedback

- Use Throttle::isWithinTimespanMs for all elapsed-time predicates in
  BME680Sensor per coding guidelines (deadline math for the async reading
  completion stays raw, as it targets an absolute timestamp)
- Make the state file name members static constexpr
- Replay tool: cast uint16_t before %u (default argument promotion), report
  malformed input lines instead of silently skipping, and fail non-zero on
  stream read errors

* Address CodeRabbit nitpicks

- Replace the local clampf helper with std::clamp (meshUtils.h's clamp drags
  in Arduino.h, which would break the estimator's standalone host build that
  the replay harness depends on)
- Trim the replay tool's file header to a two-line summary; the full build,
  capture, and tuning workflow moves to docs/bme680_iaq_replay.md

2026-08-13 13:21:16 -04:00

..

bme680_iaq_replay.md

Remove proprietary Bosch BSEC blob; open in-tree IAQ estimator for BME680 (#11381)

2026-08-13 13:21:16 -04:00