Fake IAQ values on Non-BSEC2 platforms like Platformio and the original ESP32 (#9663)

* BSEC2 Replacement
- add approximation for IAQ to non-BSEC2 platforms.
- Re-add this sensor to ESP32 targets, and refactor env_extra includes.
- Fix C++ 11 compatibility
* Check for gas resistance 0

platformio.ini

@@ -184,8 +184,8 @@ lib_deps =
 	# renovate: datasource=custom.pio depName=BH1750_WE packageName=wollewald/library/BH1750_WE
 	wollewald/BH1750_WE@1.1.10
 
-; (not included in native / portduino)
+; Common environmental sensor libraries (not included in native / portduino)
-[environmental_extra]
+[environmental_extra_common]
 lib_deps =
 	# renovate: datasource=custom.pio depName=Adafruit BMP3XX packageName=adafruit/library/Adafruit BMP3XX Library
 	adafruit/Adafruit BMP3XX Library@2.1.6
@@ -205,10 +205,6 @@ lib_deps =
 	sparkfun/SparkFun Qwiic Scale NAU7802 Arduino Library@1.0.6
 	# renovate: datasource=custom.pio depName=ClosedCube OPT3001 packageName=closedcube/library/ClosedCube OPT3001
 	closedcube/ClosedCube OPT3001@1.1.2
-	# renovate: datasource=custom.pio depName=Bosch BSEC2 packageName=boschsensortec/library/bsec2
-	boschsensortec/bsec2@1.10.2610
-	# renovate: datasource=custom.pio depName=Bosch BME68x packageName=boschsensortec/library/BME68x Sensor Library
-	boschsensortec/BME68x Sensor Library@1.3.40408
 	# renovate: datasource=git-refs depName=meshtastic-DFRobot_LarkWeatherStation packageName=https://github.com/meshtastic/DFRobot_LarkWeatherStation gitBranch=master
 	https://github.com/meshtastic/DFRobot_LarkWeatherStation/archive/4de3a9cadef0f6a5220a8a906cf9775b02b0040d.zip
 	# renovate: datasource=custom.pio depName=Sensirion Core packageName=sensirion/library/Sensirion Core
@@ -220,34 +216,18 @@ lib_deps =
 	# renovate: datasource=custom.pio depName=Sensirion I2C SCD30 packageName=sensirion/library/Sensirion I2C SCD30
 	sensirion/Sensirion I2C SCD30@1.0.0
 
-; Same as environmental_extra but without BSEC (saves ~3.5KB DRAM for original ESP32 targets)
+; Environmental sensors with BSEC2 (Bosch proprietary IAQ)
+[environmental_extra]
+lib_deps =
+	${environmental_extra_common.lib_deps}
+	# renovate: datasource=custom.pio depName=Bosch BSEC2 packageName=boschsensortec/library/bsec2
+	boschsensortec/bsec2@1.10.2610
+	# renovate: datasource=custom.pio depName=Bosch BME68x packageName=boschsensortec/library/BME68x Sensor Library
+	boschsensortec/BME68x Sensor Library@1.3.40408
+
+; Environmental sensors without BSEC (saves ~3.5KB DRAM for original ESP32 targets)
 [environmental_extra_no_bsec]
 lib_deps =
-	# renovate: datasource=custom.pio depName=Adafruit BMP3XX packageName=adafruit/library/Adafruit BMP3XX Library
+	${environmental_extra_common.lib_deps}
-	adafruit/Adafruit BMP3XX Library@2.1.6
+	# renovate: datasource=custom.pio depName=adafruit/Adafruit BME680 Library packageName=adafruit/library/Adafruit BME680
-	# renovate: datasource=custom.pio depName=Adafruit MAX1704X packageName=adafruit/library/Adafruit MAX1704X
+	adafruit/Adafruit BME680 Library@^2.0.5
-	adafruit/Adafruit MAX1704X@1.0.3
-	# renovate: datasource=custom.pio depName=Adafruit SHTC3 packageName=adafruit/library/Adafruit SHTC3 Library
-	adafruit/Adafruit SHTC3 Library@1.0.2
-	# renovate: datasource=custom.pio depName=Adafruit LPS2X packageName=adafruit/library/Adafruit LPS2X
-	adafruit/Adafruit LPS2X@2.0.6
-	# renovate: datasource=custom.pio depName=Adafruit SHT31 packageName=adafruit/library/Adafruit SHT31 Library
-	adafruit/Adafruit SHT31 Library@2.2.2
-	# renovate: datasource=custom.pio depName=Adafruit VEML7700 packageName=adafruit/library/Adafruit VEML7700 Library
-	adafruit/Adafruit VEML7700 Library@2.1.6
-	# renovate: datasource=custom.pio depName=Adafruit SHT4x packageName=adafruit/library/Adafruit SHT4x Library
-	adafruit/Adafruit SHT4x Library@1.0.5
-	# renovate: datasource=custom.pio depName=SparkFun Qwiic Scale NAU7802 packageName=sparkfun/library/SparkFun Qwiic Scale NAU7802 Arduino Library
-	sparkfun/SparkFun Qwiic Scale NAU7802 Arduino Library@1.0.6
-	# renovate: datasource=custom.pio depName=ClosedCube OPT3001 packageName=closedcube/library/ClosedCube OPT3001
-	closedcube/ClosedCube OPT3001@1.1.2
-	# renovate: datasource=git-refs depName=meshtastic-DFRobot_LarkWeatherStation packageName=https://github.com/meshtastic/DFRobot_LarkWeatherStation gitBranch=master
-	https://github.com/meshtastic/DFRobot_LarkWeatherStation/archive/4de3a9cadef0f6a5220a8a906cf9775b02b0040d.zip
-	# renovate: datasource=custom.pio depName=Sensirion Core packageName=sensirion/library/Sensirion Core
-	sensirion/Sensirion Core@0.7.3
-	# renovate: datasource=custom.pio depName=Sensirion I2C SCD4x packageName=sensirion/library/Sensirion I2C SCD4x
-	sensirion/Sensirion I2C SCD4x@1.1.0
-  # renovate: datasource=custom.pio depName=Sensirion I2C SFA3x packageName=sensirion/library/Sensirion I2C SFA3x
-	sensirion/Sensirion I2C SFA3x@1.0.0
-	# renovate: datasource=custom.pio depName=Sensirion I2C SCD30 packageName=sensirion/library/Sensirion I2C SCD30
-	sensirion/Sensirion I2C SCD30@1.0.0

src/modules/Telemetry/Sensor/BME680Sensor.cpp

@@ -8,6 +8,10 @@
 #include "SPILock.h"
 #include "TelemetrySensor.h"
 
+#if __has_include(<Adafruit_BME680.h>)
+#include <cmath>
+#endif
+
 BME680Sensor::BME680Sensor() : TelemetrySensor(meshtastic_TelemetrySensorType_BME680, "BME680") {}
 
 #if __has_include(<bsec2.h>)
@@ -96,8 +100,28 @@ bool BME680Sensor::getMetrics(meshtastic_Telemetry *measurement)
     measurement->variant.environment_metrics.temperature = bme680->readTemperature();
     measurement->variant.environment_metrics.relative_humidity = bme680->readHumidity();
     measurement->variant.environment_metrics.barometric_pressure = bme680->readPressure() / 100.0F;
-    measurement->variant.environment_metrics.gas_resistance = bme680->readGas() / 1000.0;
 
+    float gasRaw = bme680->readGas();
+    measurement->variant.environment_metrics.gas_resistance = gasRaw / 1000.0;
+
+    // IAQ approximation: humidity-compensated logarithmic mapping of gas resistance
+    // Gas sensor resistance drops with humidity; compensate to a 40% RH reference baseline
+    // Map compensated gas resistance (Ohms) to IAQ 0-500 using log-linear interpolation
+    // Clean air reference ~400 kOhm, polluted reference ~5 kOhm
+    if (gasRaw > 0.0f && !isfinite(gasRaw)) {
+
+        static constexpr float LOG_UPPER = 12.899219f;                          // log(400k)
+        static constexpr float LOG_RANGE_INV = 1.0f / (12.899219f - 8.517193f); // 1 / (log(400k) - log(5k))
+        measurement->variant.environment_metrics.has_iaq = true;
+        measurement->variant.environment_metrics.iaq = (uint16_t)(fminf(
+            fmaxf(((LOG_UPPER -
+                    logf(fmaxf(gasRaw * expf(0.035f * (measurement->variant.environment_metrics.relative_humidity - 40.0f)),
+                               1.0f))) *
+                   LOG_RANGE_INV) *
+                      500.0f,
+                  0.0f),
+            500.0f));
+    }
 #endif
     return true;
 }

src/modules/Telemetry/Sensor/BME680Sensor.h

@@ -28,7 +28,7 @@ class BME680Sensor : public TelemetrySensor
 #else
     using BME680Ptr = std::unique_ptr<Adafruit_BME680>;
 
-    static BME680Ptr makeBME680(TwoWire *bus) { return std::make_unique<Adafruit_BME680>(bus); }
+    static BME680Ptr makeBME680(TwoWire *bus) { return BME680Ptr(new Adafruit_BME680(bus)); }
 
     BME680Ptr bme680;
 #endif