sns: Add BME680 (#2295)

Add support for BME680 using libalgobsec proprietary algorithms for precise Indoor Air Quality (IAQ) measurement. Unlike traditional CO2 sensors - and good ones are expensive - it measures nearly all VOCs compounds in the air (plus other gases) and compensates those measurements with its built-in temperature and humidity sensors to determine indoor air quality.

Co-authored-by: Max Prokhorov <prokhorov.max@outlook.com>

README.md

@@ -93,6 +93,7 @@ Since November 2018, Max Prokhorov (**@mcspr**) is also actively working as a co
     * Environment
         * **DHT11 / DHT12 / DHT22 / DHT21 / AM2301 / Itead's SI7021**
         * **BMP180**, **BMP280** and **BME280** pressure, humidity (BME280) and temperature (BMP280 & BME280) sensor by Bosch
+        * **BME680** pressure, humidity, temperature and gas sensor by Bosch with support for Bosch's proprietary library BSEC for accurate Indoor Air Quality (IAQ) monitoring (⚠️ [learn more](https://github.com/xoseperez/espurna/wiki/Sensors#bme680-environmental-sensor))
         * **TMP35** and **TMP36** analog temperature sensors
         * **MAX6675** temperature sensor
         * **NTC** temperature sensors

code/espurna/board.cpp

@@ -203,6 +203,9 @@ PROGMEM const char espurna_sensors[] =
     #if BMX280_SUPPORT
         "BMX280 "
     #endif
+    #if BME680_SUPPORT
+        "BME680 "
+    #endif
     #if CSE7766_SUPPORT
         "CSE7766 "
     #endif

code/espurna/config/arduino.h

@@ -229,6 +229,7 @@
 //#define BH1750_SUPPORT         1
 //#define BMP180_SUPPORT         1
 //#define BMX280_SUPPORT         1
+//#define BME680_SUPPORT         1
 //#define CSE7766_SUPPORT        1
 //#define DALLAS_SUPPORT         1
 //#define DHT_SUPPORT            1

code/espurna/config/dependencies.h

@@ -221,3 +221,12 @@
 #warning "MQTT_MAX_PACKET_SIZE should be set in `build_flags = ...` of the environment! Default value is used instead."
 #endif
 #endif
+
+//------------------------------------------------------------------------------
+// Disable BME680 support if using Core version 2.3.0 due to memory constraints.
+
+#if BME680_SUPPORT && defined(ARDUINO_ESP8266_RELEASE_2_3_0)
+#warning "BME680_SUPPORT is not available when using Arduino Core 2.3.0 due to memory constraints. Please use Arduino Core 2.6.3+ instead (or set `platform = ${common.platform_latest}` for the latest version)."
+#undef BME680_SUPPORT
+#define BME680_SUPPORT 0
+#endif

code/espurna/config/general.h

@@ -667,7 +667,7 @@
 #endif
 
 // ref: https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/kconfig.html#config-lwip-esp-gratuitous-arp
-// ref: https://github.com/xoseperez/espurna/pull/1877#issuecomment-525612546 
+// ref: https://github.com/xoseperez/espurna/pull/1877#issuecomment-525612546
 //
 // Broadcast gratuitous ARP periodically to update ARP tables on the AP and all devices on the same network.
 // Helps to solve compatibility issues when ESP fails to timely reply to ARP requests, causing the device's ARP table entry to expire.
@@ -1028,7 +1028,7 @@
 #endif
 
 #ifndef MQTT_SECURE_CLIENT_MFLN
-#define MQTT_SECURE_CLIENT_MFLN     SECURE_CLIENT_MFLN  // Use global MFLN setting by default 
+#define MQTT_SECURE_CLIENT_MFLN     SECURE_CLIENT_MFLN  // Use global MFLN setting by default
 #endif
 
 #ifndef MQTT_SECURE_CLIENT_INCLUDE_CA

code/espurna/config/sensors.h

@@ -782,39 +782,39 @@
 // LDR sensor
 // Enable support by passing LDR_SUPPORT=1 build flag
 //------------------------------------------------------------------------------
- 
+
 #ifndef LDR_SUPPORT
 #define LDR_SUPPORT                     0
 #endif
- 
+
 #ifndef LDR_SAMPLES
 #define LDR_SAMPLES                     10      // Number of samples
 #endif
- 
+
 #ifndef LDR_DELAY
 #define LDR_DELAY                       0       // Delay between samples in micros
 #endif
- 
+
 #ifndef LDR_TYPE
 #define LDR_TYPE                        LDR_GL5528
 #endif
- 
+
 #ifndef LDR_ON_GROUND
 #define LDR_ON_GROUND                   true
 #endif
- 
+
 #ifndef LDR_RESISTOR
 #define LDR_RESISTOR                    10000   // Resistance
 #endif
- 
+
 #ifndef LDR_MULTIPLICATION
 #define LDR_MULTIPLICATION              32017200
 #endif
- 
+
 #ifndef LDR_POWER
 #define LDR_POWER                       1.5832
 #endif
- 
+
 //------------------------------------------------------------------------------
 // MHZ19 CO2 sensor
 // Enable support by passing MHZ19_SUPPORT=1 build flag
@@ -1303,6 +1303,29 @@
 #define SI1145_ADDRESS                   0x60
 #endif
 
+//------------------------------------------------------------------------------
+// BME680
+// Enable support by passing BME680_SUPPORT=1 build flag
+//------------------------------------------------------------------------------
+
+#ifndef BME680_SUPPORT
+#define BME680_SUPPORT                              0
+#endif
+
+#ifndef BME680_I2C_ADDRESS
+#define BME680_I2C_ADDRESS                          0x00                                   // 0x00 means auto
+#endif
+
+#ifndef BME680_BSEC_CONFIG
+#define BME680_BSEC_CONFIG                          BME680_BSEC_CONFIG_GENERIC_33V_3S_4D   // BSEC config config value. By default, 3.3V as supply voltage,
+#endif                                                                                     // 3 seconds as maximum time between bsec_sensor_control` calls
+                                                                                           // and 4 days as the time considered for background calibration.
+
+#ifndef BME680_STATE_SAVE_INTERVAL
+#define BME680_STATE_SAVE_INTERVAL                  0                                      // How frequently (in milliseconds) should state be stored in
+#endif                                                                                     // non-volatile memory. A common value would be every 6h or
+                                                                                           // 360 * 60 * 1000 milliseconds. By default, this is disabled.
+
 // -----------------------------------------------------------------------------
 // ADC
 // -----------------------------------------------------------------------------
@@ -1356,6 +1379,7 @@
     BH1750_SUPPORT || \
     BMP180_SUPPORT || \
     BMX280_SUPPORT || \
+    BME680_SUPPORT || \
     EMON_ADC121_SUPPORT || \
     EMON_ADS1X15_SUPPORT || \
     SHT3X_I2C_SUPPORT || \
@@ -1391,6 +1415,7 @@
     ANALOG_SUPPORT || \
     BH1750_SUPPORT || \
     BMP180_SUPPORT || \
+    BME680_SUPPORT || \
     BMX280_SUPPORT || \
     CSE7766_SUPPORT || \
     DALLAS_SUPPORT || \

code/espurna/config/types.h

@@ -333,6 +333,7 @@
 #define SENSOR_SI1145_ID            39
 #define SENSOR_HDC1080_ID           40
 #define SENSOR_PZEM004TV30_ID       41
+#define SENSOR_BME680_ID            42
 
 //--------------------------------------------------------------------------------
 // Magnitudes
@@ -372,8 +373,12 @@
 #define MAGNITUDE_RESISTANCE        30
 #define MAGNITUDE_PH                31
 #define MAGNITUDE_FREQUENCY         32
+#define MAGNITUDE_IAQ               33
+#define MAGNITUDE_IAQ_ACCURACY      34
+#define MAGNITUDE_IAQ_STATIC        35
+#define MAGNITUDE_VOC               36
 
-#define MAGNITUDE_MAX               33
+#define MAGNITUDE_MAX               38
 
 #define SENSOR_ERROR_OK             0       // No error
 #define SENSOR_ERROR_OUT_OF_RANGE   1       // Result out of sensor range

code/espurna/debug.cpp

@@ -328,7 +328,7 @@ DebugLogMode convert(const String& value) {
 
 void debugConfigureBoot() {
     static_assert(
-        std::is_same<int, std::underlying_type<DebugLogMode>::type>::value, 
+        std::is_same<int, std::underlying_type<DebugLogMode>::type>::value,
         "should be able to match DebugLogMode with int"
     );
 

code/espurna/sensor.cpp

@@ -59,6 +59,10 @@ Copyright (C) 2016-2019 by Xose Pérez <xose dot perez at gmail dot com>
     #include "sensors/BMX280Sensor.h"
 #endif
 
+#if BME680_SUPPORT
+    #include "sensors/BME680Sensor.h"
+#endif
+
 #if CSE7766_SUPPORT
     #include "sensors/CSE7766Sensor.h"
 #endif
@@ -515,6 +519,8 @@ sensor_magnitude_t::sensor_magnitude_t(unsigned char slot, unsigned char index_l
     ++_counts[type];
 
     switch (type) {
+        case MAGNITUDE_IAQ:
+        case MAGNITUDE_IAQ_STATIC:
         case MAGNITUDE_ENERGY:
             filter = new LastFilter();
             break;
@@ -641,6 +647,18 @@ String magnitudeTopic(unsigned char type) {
         case MAGNITUDE_CO2:
             result = F("co2");
             break;
+        case MAGNITUDE_VOC:
+            result = F("voc");
+            break;
+        case MAGNITUDE_IAQ:
+            result = F("iaq");
+            break;
+        case MAGNITUDE_IAQ_ACCURACY:
+            result = F("iaq_accuracy");
+            break;
+        case MAGNITUDE_IAQ_STATIC:
+            result = F("iaq_static");
+            break;
         case MAGNITUDE_LUX:
             result = F("lux");
             break;
@@ -927,6 +945,10 @@ const char * const _magnitudeSettingsPrefix(unsigned char type) {
     case MAGNITUDE_PM2dot5: return "pm1dot5";
     case MAGNITUDE_PM10: return "pm10";
     case MAGNITUDE_CO2: return "co2";
+    case MAGNITUDE_VOC: return "voc";
+    case MAGNITUDE_IAQ: return "iaq";
+    case MAGNITUDE_IAQ_ACCURACY: return "iaqAccuracy";
+    case MAGNITUDE_IAQ_STATIC: return "iaqStatic";
     case MAGNITUDE_LUX: return "lux";
     case MAGNITUDE_UVA: return "uva";
     case MAGNITUDE_UVB: return "uvb";
@@ -1155,6 +1177,18 @@ String magnitudeName(unsigned char type) {
         case MAGNITUDE_CO2:
             result = F("CO2");
             break;
+        case MAGNITUDE_VOC:
+            result = F("VOC");
+            break;
+        case MAGNITUDE_IAQ_STATIC:
+            result = F("IAQ (Static)");
+            break;
+        case MAGNITUDE_IAQ:
+            result = F("IAQ");
+            break;
+        case MAGNITUDE_IAQ_ACCURACY:
+            result = F("IAQ Accuracy");
+            break;
         case MAGNITUDE_LUX:
             result = F("Lux");
             break;
@@ -1570,6 +1604,14 @@ void _sensorLoad() {
     }
     #endif
 
+    #if BME680_SUPPORT
+    {
+        BME680Sensor * sensor = new BME680Sensor();
+        sensor->setAddress(BME680_I2C_ADDRESS);
+        _sensors.push_back(sensor);
+    }
+    #endif
+
     #if CSE7766_SUPPORT
     {
         CSE7766Sensor * sensor = new CSE7766Sensor();
@@ -1986,7 +2028,7 @@ void _sensorLoad() {
         _sensors.push_back(sensor);
     }
     #endif
-	
+
     #if T6613_SUPPORT
     {
         T6613Sensor * sensor = new T6613Sensor();

code/espurna/sensors/BME680Sensor.h

@@ -0,0 +1,344 @@
+// -----------------------------------------------------------------------------
+// BME680 Sensor over I2C
+// Copyright (C) 2020 by Rui Marinho <ruipmarinho at gmail dot com>
+//
+// The BSEC software binaries and includes are only available for use after accepting its software
+// license agreement. By enabling this sensor integration, you are agreeing to the terms of the license
+// agreement available at the following URL:
+//
+// https://ae-bst.resource.bosch.com/media/_tech/media/bsec/2017-07-17_ClickThrough_License_Terms_Environmentalib_SW_CLEAN.pdf
+//
+// The Arduino wrapper and BME680 Sensor API used for this integration are licensed under the following terms:
+//
+//   Copyright (c) 2020 Bosch Sensortec GmbH. All rights reserved.
+//
+//   BSD-3-Clause
+//
+//   Redistribution and use in source and binary forms, with or without
+//   modification, are permitted provided that the following conditions are met:
+//
+//   1. Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//
+//   2. Redistributions in binary form must reproduce the above copyright
+//      notice, this list of conditions and the following disclaimer in the
+//      documentation and/or other materials provided with the distribution.
+//
+//   3. Neither the name of the copyright holder nor the names of its
+//      contributors may be used to endorse or promote products derived from
+//      this software without specific prior written permission.
+//
+//   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+//   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+//   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+//   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+//   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+//   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+//   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+//   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+//   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+//   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+//   IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+//   POSSIBILITY OF SUCH DAMAGE.
+//
+// For more details, please refer to https://github.com/BoschSensortec/BSEC-Arduino-library.
+// -----------------------------------------------------------------------------
+
+#if SENSOR_SUPPORT && BME680_SUPPORT
+
+#pragma once
+
+#include <Arduino.h>
+#include <bsec.h>
+
+#include "I2CSensor.h"
+
+// Available configuration modes based on parameters:
+// voltage / maximum time between sensor calls / time considered
+// for background calibration.
+#define BME680_BSEC_CONFIG_GENERIC_18V_3S_4D        0
+#define BME680_BSEC_CONFIG_GENERIC_18V_3S_28D       1
+#define BME680_BSEC_CONFIG_GENERIC_18V_300S_4D      2
+#define BME680_BSEC_CONFIG_GENERIC_18V_300S_28D     3
+#define BME680_BSEC_CONFIG_GENERIC_33V_3S_4D        4
+#define BME680_BSEC_CONFIG_GENERIC_33V_3S_28D       5
+#define BME680_BSEC_CONFIG_GENERIC_33V_300S_4D      6
+#define BME680_BSEC_CONFIG_GENERIC_33V_300S_28D     7
+
+const uint8_t bsec_config_iaq[] = {
+  #if BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_18V_3S_4D
+    #include <config/generic_18v_3s_28d/bsec_iaq.txt>
+  #elif BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_18V_3S_28D
+    #include <config/generic_18v_300s_4d/bsec_iaq.txt>
+  #elif BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_18V_300S_4D
+    #include <config/generic_18v_300s_28d/bsec_iaq.txt>
+  #elif BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_18V_300S_28D
+    #include <config/generic_33v_3s_4d/bsec_iaq.txt>
+  #elif BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_33V_3S_4D
+    #include <config/generic_33v_3s_28d/bsec_iaq.txt>
+  #elif BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_33V_3S_28D
+    #include <config/generic_33v_300s_4d/bsec_iaq.txt>
+  #elif BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_33V_300S_4D
+    #include <config/generic_33v_300s_28d/bsec_iaq.txt>
+  #elif BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_33V_300S_28D
+    #include <config/generic_33v_3s_4d/bsec_iaq.txt>
+  #endif
+};
+
+class BME680Sensor : public I2CSensor<> {
+
+    public:
+
+        // ---------------------------------------------------------------------
+        // Public
+        // ---------------------------------------------------------------------
+
+        BME680Sensor() {
+            _sensor_id = SENSOR_BME680_ID;
+            _count = 9;
+        }
+
+        // ---------------------------------------------------------------------
+        // Sensor API
+        // ---------------------------------------------------------------------
+
+        void begin() {
+            if (!_dirty) {
+              return;
+            }
+
+            // I2C auto-discover
+            unsigned char addresses[] = {BME680_I2C_ADDR_PRIMARY, BME680_I2C_ADDR_SECONDARY};
+            _address = _begin_i2c(_address, sizeof(addresses), addresses);
+            if (_address == 0) return;
+
+            iaqSensor.begin(_address, Wire);
+
+            #if SENSOR_DEBUG
+                DEBUG_MSG("[BME680] BSEC library version v%u.%u.%u.%u\n",
+                  iaqSensor.version.major,
+                  iaqSensor.version.minor,
+                  iaqSensor.version.major_bugfix,
+                  iaqSensor.version.minor_bugfix
+                );
+            #endif
+
+            if (!_isSensorOk()) {
+              _error = SENSOR_ERROR_OTHER;
+              return;
+            }
+
+            iaqSensor.setConfig(bsec_config_iaq);
+
+            _loadState();
+
+            float sampleRate;
+
+            // BSEC configuration with 300s allows for the sensor to sleep for 300s
+            // on the ULP mode in order to minimize power consumption.
+            if (BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_18V_300S_4D ||
+              BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_18V_300S_4D ||
+              BME680_BSEC_CONFIG == BME680_BSEC_CONFIG_GENERIC_18V_300S_4D) {
+              sampleRate = BSEC_SAMPLE_RATE_ULP;
+            } else {
+              sampleRate = BSEC_SAMPLE_RATE_LP;
+            }
+
+            iaqSensor.updateSubscription(sensorList, 12, sampleRate);
+
+            if (!_isSensorOk()) {
+              _error = SENSOR_ERROR_OTHER;
+              return;
+            }
+
+            _ready = true;
+            _dirty = false;
+        }
+
+        // Descriptive name of the sensor
+        String description() {
+            char buffer[21];
+            snprintf(buffer, sizeof(buffer), "BME680 @ I2C (0x%02X)", _address);
+            return String(buffer);
+        }
+
+        // Type for slot # index
+        unsigned char type(unsigned char index) {
+            if (index == 0) return MAGNITUDE_TEMPERATURE;
+            if (index == 1) return MAGNITUDE_HUMIDITY;
+            if (index == 2) return MAGNITUDE_PRESSURE;
+            if (index == 3) return MAGNITUDE_RESISTANCE;
+            if (index == 4) return MAGNITUDE_IAQ_ACCURACY;
+            if (index == 5) return MAGNITUDE_IAQ;
+            if (index == 6) return MAGNITUDE_IAQ_STATIC;
+            if (index == 7) return MAGNITUDE_CO2;
+            if (index == 8) return MAGNITUDE_VOC;
+
+            return MAGNITUDE_NONE;
+        }
+
+        void _loadState() {
+            String storedState = getSetting("bsecState");
+
+            if (storedState.length() == 0) {
+              #if SENSOR_DEBUG
+                  DEBUG_MSG("[BME680] Previous state not found\n");
+              #endif
+
+              return;
+            }
+
+            hexDecode(storedState.c_str(), storedState.length(), _bsecState, sizeof(_bsecState));
+
+            iaqSensor.setState(_bsecState);
+
+            #if SENSOR_DEBUG
+                DEBUG_MSG("[BME680] Loaded previous state %s\n", storedState.c_str());
+            #endif
+        }
+
+        void _saveState() {
+            if (BME680_STATE_SAVE_INTERVAL == 0) {
+                return;
+            }
+
+            static unsigned long last_millis = 0;
+
+            if (_iaqAccuracy < 3 || (millis() - last_millis < BME680_STATE_SAVE_INTERVAL)) {
+                return;
+            }
+
+            iaqSensor.getState(_bsecState);
+
+            char storedState[BSEC_MAX_STATE_BLOB_SIZE * 2 + 1] = {0};
+            hexEncode(_bsecState, BSEC_MAX_STATE_BLOB_SIZE, storedState, sizeof(storedState));
+
+            setSetting("bsecState", storedState);
+
+            last_millis = millis();
+        }
+
+        // The maximum allowed time between two `bsec_sensor_control` calls depends on
+        // configuration profile `bsec_config_iaq` below.
+        void tick() {
+            _error = SENSOR_ERROR_OK;
+
+            if (!_isSensorOk()) {
+              _error = SENSOR_ERROR_OTHER;
+              return;
+            }
+
+            if (iaqSensor.run()) {
+              _rawTemperature = iaqSensor.rawTemperature;
+              _rawHumidity = iaqSensor.rawHumidity;
+              _temperature = iaqSensor.temperature;
+              _humidity = iaqSensor.humidity;
+              _pressure = iaqSensor.pressure / 100;
+              _gasResistance = iaqSensor.gasResistance;
+              _iaqAccuracy = iaqSensor.iaqAccuracy;
+              _iaq = iaqSensor.iaq;
+              _iaqStatic = iaqSensor.staticIaq;
+              _co2Equivalent = iaqSensor.co2Equivalent;
+              _breathVocEquivalent = iaqSensor.breathVocEquivalent;
+
+              _saveState();
+            }
+        }
+
+        // Current value for slot # index
+        double value(unsigned char index) {
+            if (index == 0) return _temperature;
+            if (index == 1) return _humidity;
+            if (index == 2) return _pressure;
+            if (index == 3) return _gasResistance;
+            if (index == 4) return _iaqAccuracy;
+            if (index == 5) return _iaq;
+            if (index == 6) return _iaqStatic;
+            if (index == 7) return _co2Equivalent;
+            if (index == 8) return _breathVocEquivalent;
+
+            return 0;
+        }
+
+    protected:
+
+        bool _isSensorOk() {
+            if (iaqSensor.status == BSEC_OK && iaqSensor.bme680Status == BME680_OK) {
+                return true;
+            }
+
+            #if SENSOR_DEBUG
+            if (iaqSensor.status != BSEC_OK) {
+              if (iaqSensor.status < BSEC_OK) {
+                DEBUG_MSG("[BME680] BSEC error code %d\n", iaqSensor.status);
+              } else {
+                DEBUG_MSG("[BME680] BSEC warning code %d\n", iaqSensor.status);
+              }
+            }
+            #endif
+
+            #if SENSOR_DEBUG
+            if (iaqSensor.bme680Status != BME680_OK) {
+              if (iaqSensor.bme680Status < BME680_OK) {
+                DEBUG_MSG("[BME680] Error code %d\n", iaqSensor.bme680Status);
+              } else {
+                DEBUG_MSG("[BME680] Warning code %d\n", iaqSensor.bme680Status);
+              }
+            }
+            #endif
+
+            return false;
+        }
+
+        bsec_virtual_sensor_t sensorList[12] = {
+            BSEC_OUTPUT_RAW_TEMPERATURE,                      // Unscaled (raw) temperature (ºC).
+
+            BSEC_OUTPUT_RAW_PRESSURE,                         // Unscaled (raw) pressure (Pa).
+
+            BSEC_OUTPUT_RAW_HUMIDITY,                         // Unscaled (raw) relative humidity (%).
+
+            BSEC_OUTPUT_RAW_GAS,                              // Gas resistance (Ohm). The resistance value changes according to the
+                                                              // VOC concentration (the higher the concentration of reducing VOCs,
+                                                              // the lower the resistance and vice versa).
+
+            BSEC_OUTPUT_IAQ,                                  // Scaled Indoor Air Quality based on the recent sensor history, ideal
+                                                              // for mobile applications (e.g. carry-on devices). The scale ranges from
+                                                              // 0 (clean air) to 500 (heavily polluted air). The automatic background
+                                                              // calibration process ensures that consistent IAQ performance is achieved
+                                                              // after certain of days (depending on BSEC configuration - 4d or 28d).
+
+            BSEC_OUTPUT_STATIC_IAQ,                           // Unscaled Indoor Air Quality, optimized for stationary applications
+                                                              // (e.g. fixed indoor devices).
+            BSEC_OUTPUT_CO2_EQUIVALENT,                       // Estimate of CO2 measured in the air.
+            BSEC_OUTPUT_BREATH_VOC_EQUIVALENT,                // Breath VOC represents the most important compounds in an exhaled
+                                                              // breath of healthy humans.
+
+            BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_TEMPERATURE,  // Temperature compensated for the influence of sensor heater (ºC).
+
+            BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_HUMIDITY,     // Relative humidity compensated for the influence of sensor heater (%).
+
+            BSEC_OUTPUT_STABILIZATION_STATUS,                 // Indicates initial stabilization status of the gas sensor element:
+                                                              // ongoing (0) or finished (1).
+
+            BSEC_OUTPUT_RUN_IN_STATUS,                        // Indicates power-on stabilization status of the gas sensor element:
+                                                              // ongoing (0) or finished (1).
+        };
+
+        float _breathVocEquivalent = 0.0f;
+        float _co2Equivalent = 0.0f;
+        float _gasResistance = 0.0f;
+        float _humidity = 0.0f;
+        float _iaq = 0.0f;
+        float _pressure = 0.0f;
+        float _rawHumidity = 0.0f;
+        float _rawTemperature = 0.0f;
+        float _temperature = 0.0f;
+        uint8_t _bsecState[BSEC_MAX_STATE_BLOB_SIZE] = {0};
+        uint8_t _iaqAccuracy = 0;
+        float _iaqStatic = 0;
+
+        Bsec iaqSensor;
+
+};
+
+#endif // SENSOR_SUPPORT && BME680_SUPPORT

code/espurna/sensors/BaseSensor.h

@@ -117,9 +117,10 @@ class BaseSensor {
                 case MAGNITUDE_PM1dot0:
                 case MAGNITUDE_PM2dot5:
                     return sensor::Unit::MicrogrammPerCubicMeter;
+                case MAGNITUDE_CO:
                 case MAGNITUDE_CO2:
                 case MAGNITUDE_NO2:
-                case MAGNITUDE_CO:
+                case MAGNITUDE_VOC:
                     return sensor::Unit::PartsPerMillion;
                 case MAGNITUDE_LUX:
                     return sensor::Unit::Lux;

code/platformio.ini

@@ -155,6 +155,7 @@ lib_deps =
     https://github.com/mcleng/MAX6675-Library#2.0.1
     https://github.com/ThingPulse/esp8266-oled-ssd1306#3398c97
     Adafruit SI1145 Library@~1.1.1
+    https://github.com/BoschSensortec/BSEC-Arduino-library.git#c5503e0
 
 # ------------------------------------------------------------------------------
 # COMMON ENVIRONMENT SETTINGS:
@@ -252,7 +253,7 @@ board_build.ldscript = ${common.ldscript_1m}
 platform = ${common.platform_latest}
 board = ${common.board_2m}
 platform_packages =
-    ${common.git_platform_packages} 
+    ${common.git_platform_packages}
 board_build.ldscript = ${common.ldscript_2m}
 
 [env:esp8266-4m-git-base]

code/scripts/espurna_utils/__init__.py

@@ -22,6 +22,7 @@
 from .checks import check_cppcheck, check_printsize
 from .float_support import remove_float_support
 from .ldscripts import ldscripts_inject_libpath
+from .libalgobsec import libalgobsec_inject_patcher
 from .lwip import lwip_inject_patcher
 from .postmortem import dummy_ets_printf
 from .git import app_inject_revision
@@ -33,6 +34,7 @@ __all__ = [
     "check_printsize",
     "remove_float_support",
     "ldscripts_inject_libpath",
+    "libalgobsec_inject_patcher",
     "lwip_inject_patcher",
     "dummy_ets_printf",
     "app_inject_revision",

code/scripts/espurna_utils/ldscripts.py

@@ -1,6 +1,5 @@
 import os
 
-
 def ldscripts_inject_libpath(env):
 
     platform = env.PioPlatform()

code/scripts/espurna_utils/libalgobsec.py

@@ -0,0 +1,69 @@
+import os
+import sys
+
+
+def libalgobsec_inject_patcher(env):
+    libalgobsec_builder = next(
+        (
+            builder
+            for builder in env.GetLibBuilders()
+            if builder.name == "BSEC Software Library"
+        ),
+        None,
+    )
+
+    if libalgobsec_builder is None:
+        return
+
+    def process_archive(target, source, env):
+        import subprocess
+
+        # Allows `import espurna_utils` for external scripts, where we might not be within scons runtime
+        from SCons.Script import Delete, Mkdir
+
+        tmpdir = env.get(
+            "ESPURNA_LIBALGOBSEC_PATCHER_TMPDIR",
+            os.path.join(str(target[0].get_dir()), "_tmpdir"),
+        )
+
+        env.Execute(Mkdir(tmpdir))
+
+        # XXX: $AR does not support output argument for the extraction
+        #      always switch into tmpdir when running commands
+        def run(cmd):
+            sys.stdout.write(" ".join(cmd))
+            sys.stdout.write("\n")
+            subprocess.check_call(cmd, cwd=tmpdir)
+
+        run([env.subst("$AR"), "x", source[0].abspath])
+
+        names = []
+        for infilename in os.listdir(tmpdir):
+            newname = infilename
+            if not infilename.endswith(".c.o"):
+                newname = infilename.replace(".o", ".c.o")
+            os.rename(os.path.join(tmpdir, infilename), os.path.join(tmpdir, newname))
+            names.append(newname)
+
+        pack_cmd = [env.subst("$AR"), "cr", target[0].abspath]
+        pack_cmd.extend(names)
+        run(pack_cmd)
+
+        env.Execute(Delete(tmpdir))
+
+    # Instead of replacing the file in-place, link with the patched version
+    libalgobsec_dir = os.path.join(libalgobsec_builder.src_dir, "esp8266")
+
+    target = env.File(
+        "libalgobsec.a", directory=env.subst("$BUILD_DIR/libalgobsec_patched")
+    )
+    source = env.File("libalgobsec.a", directory=libalgobsec_dir)
+
+    command = env.Command(target, source, process_archive)
+    patcher = env.Alias("patch-libalgobsec", command)
+
+    env.Append(LIBPATH=[target.get_dir()])
+    env.Append(LIBS=["algobsec"])
+
+    env.Depends("$BUILD_DIR/${PROGNAME}.elf", patcher)
+

code/scripts/pio_main.py

@@ -13,6 +13,7 @@ from espurna_utils import (
     check_printsize,
     remove_float_support,
     ldscripts_inject_libpath,
+    libalgobsec_inject_patcher,
     lwip_inject_patcher,
     app_inject_revision,
     dummy_ets_printf,
@@ -48,6 +49,9 @@ if "DISABLE_POSTMORTEM_STACKDUMP" in env["CPPFLAGS"]:
         "$BUILD_DIR/FrameworkArduino/core_esp8266_postmortem.cpp.o", dummy_ets_printf
     )
 
+# place bsec's libalgobsec.a sections in the flash to avoid "section ‘.text' will not fit in region 'iram1_0_seg'" error
+libalgobsec_inject_patcher(env)
+
 # patch lwip1 sources conditionally:
 # https://github.com/xoseperez/espurna/issues/1610
 lwip_inject_patcher(env)

code/test/build/sensor.h

@@ -3,6 +3,7 @@
 #define BH1750_SUPPORT 1
 #define BMP180_SUPPORT 1
 #define BMX280_SUPPORT 1
+#define BME680_SUPPORT 1
 #define DALLAS_SUPPORT 1
 #define DHT_SUPPORT 1
 #define DIGITAL_SUPPORT 1