Merge pull request #375 from airgradienthq/feat/sps30-ooa

Add SPS30 PM sensor support for OPEN_AIR_OUTDOOR

docs/local-server.md

@@ -142,7 +142,7 @@ If the monitor is set up on the AirGradient dashboard, it will also receive the
 | `country`                         | Country where the device is.                                     | String  | Country code as [ALPHA-2 notation](https://www.iban.com/country-codes)                                                                  | `{"country": "TH"}`                             |
 | `model`                           | Hardware identifier (only GET).                                  | String  | I-9PSL-DE                                                                                                                               | `{"model": "I-9PSL-DE"}`                        |
 | `pmStandard`                      | Particle matter standard used on the display.                    | String  | `ugm3`: ug/m3 <br> `us-aqi`: USAQI                                                                                                      | `{"pmStandard": "ugm3"}`                        |
-| `ledBarMode`                      | Mode in which the led bar can be set.                            | String  | `co2`: LED bar displays CO2 <br>`pm`: LED bar displays PM <br>`off`: Turn off LED bar                                                   | `{"ledBarMode": "off"}`                         |
+| `ledBarMode`                      | Mode in which the led bar can be set.                            | String  | `co2`: LED bar displays CO2 <br>`pm`: LED bar displays PM <br>`iaqs`: LED bar displays GO IAQS Starter Score (PM2.5 + CO2) <br>`off`: Turn off LED bar | `{"ledBarMode": "off"}`                         |
 | `displayBrightness`               | Brightness of the Display.                                       | Number  | 0-100                                                                                                                                   | `{"displayBrightness": 50}`                     |
 | `ledBarBrightness`                | Brightness of the LEDBar.                                        | Number  | 0-100                                                                                                                                   | `{"ledBarBrightness": 40}`                      |
 | `abcDays`                         | Number of days for CO2 automatic baseline calibration.           | Number  | Maximum 200 days. Default 8 days.                                                                                                       | `{"abcDays": 8}`                                |

examples/OneOpenAir/OneOpenAir.ino

@@ -140,7 +140,7 @@ static void configUpdateHandle(void);
 static void updateDisplayAndLedBar(void);
 static void updateTvoc(void);
 static void updatePm(void);
-static void updateSPS30(void);
+static void updateSPS30(SPS30 &sensor, int channel);
 static void sendDataToServer(void);
 static void tempHumUpdate(void);
 static void co2Update(void);
@@ -336,7 +336,7 @@ void loop() {
     co2Schedule.run();
   }
   if (configuration.hasSensorPMS1 || configuration.hasSensorPMS2 ||
-      configuration.hasSensorSPS30) {
+      configuration.hasSensorSPS30_1 || configuration.hasSensorSPS30_2) {
     pmsSchedule.run();
   }
   if (ag->isOne()) {
@@ -829,9 +829,9 @@ static void oneIndoorInit(void) {
     Serial.println("PMS5003 not found, trying SPS30...");
     configuration.hasSensorPMS1 = false;
 
-    if (ag->sps30.begin(Serial0)) {
+    if (ag->sps30_1.begin(Serial0)) {
       Serial.println("SPS30 detected on Serial0");
-      configuration.hasSensorSPS30 = true;
+      configuration.hasSensorSPS30_1 = true;
     } else {
       Serial.println("SPS30 not found either");
       dispSensorNotFound("PM sensor");
@@ -888,56 +888,100 @@ static void openAirInit(void) {
     }
   }
 
-  /** Attempt to detect PM sensors */
-  if (fwMode == FW_MODE_O_1PST) {
-    bool pmInitSuccess = false;
+  /**
+   * Attempt to detect PM sensors on available serial ports.
+   * Per-port order: PMS5003T first (@9600), fallback to SPS30 (@115200).
+   * For single-PM modes the detected sensor is always assigned to channel 1.
+   * For dual-PM modes Serial0 → channel 1, Serial1 → channel 2.
+   */
+  auto detectPmOnSerial = [](HardwareSerial &serial, PMS5003T &pms, SPS30 &sps,
+                             const char *portName) -> int {
+    // Returns: 0 = none, 1 = PMS5003T, 2 = SPS30
+    if (pms.begin(serial)) {
+      Serial.printf("Detected PMS5003T on %s\n", portName);
+      return 1;
+    }
+    Serial.printf("PMS5003T not found on %s, trying SPS30...\n", portName);
+    if (sps.begin(serial)) {
+      Serial.printf("Detected SPS30 on %s\n", portName);
+      return 2;
+    }
+    Serial.printf("No PM sensor detected on %s\n", portName);
+    return 0;
+  };
+
+  if (fwMode == FW_MODE_O_1PST || fwMode == FW_MODE_O_1PS) {
+    // Single PM channel expected — try Serial0 first, fallback Serial1
+    configuration.hasSensorPMS1 = false;
+    configuration.hasSensorPMS2 = false;
+    bool pmFound = false;
+
     if (serial0Available) {
-      if (ag->pms5003t_1.begin(Serial0) == false) {
-        configuration.hasSensorPMS1 = false;
-        Serial.println("No PM sensor detected on Serial0");
-      } else {
+      int result =
+          detectPmOnSerial(Serial0, ag->pms5003t_1, ag->sps30_1, "Serial0");
+      if (result == 1) {
+        configuration.hasSensorPMS1 = true;
         serial0Available = false;
-        pmInitSuccess = true;
-        Serial.println("Detected PM 1 on Serial0");
+        pmFound = true;
+      } else if (result == 2) {
+        configuration.hasSensorSPS30_1 = true;
+        serial0Available = false;
+        pmFound = true;
       }
     }
-    if (pmInitSuccess == false) {
-      if (serial1Available) {
-        if (ag->pms5003t_1.begin(Serial1) == false) {
-          configuration.hasSensorPMS1 = false;
-          Serial.println("No PM sensor detected on Serial1");
-        } else {
-          serial1Available = false;
-          Serial.println("Detected PM 1 on Serial1");
-        }
+    if (!pmFound && serial1Available) {
+      int result =
+          detectPmOnSerial(Serial1, ag->pms5003t_1, ag->sps30_1, "Serial1");
+      if (result == 1) {
+        configuration.hasSensorPMS1 = true;
+        serial1Available = false;
+      } else if (result == 2) {
+        configuration.hasSensorSPS30_1 = true;
+        serial1Available = false;
       }
     }
-    configuration.hasSensorPMS2 = false; // Disable PM2
   } else {
-    if (ag->pms5003t_1.begin(Serial0) == false) {
-      configuration.hasSensorPMS1 = false;
-      Serial.println("No PM sensor detected on Serial0");
-    } else {
-      Serial.println("Detected PM 1 on Serial0");
-    }
-    if (ag->pms5003t_2.begin(Serial1) == false) {
-      configuration.hasSensorPMS2 = false;
-      Serial.println("No PM sensor detected on Serial1");
-    } else {
-      Serial.println("Detected PM 2 on Serial1");
+    // Dual PM channel modes (O_1PPT / O_1PP) — Serial0 → ch1, Serial1 → ch2
+    configuration.hasSensorPMS1 = false;
+    configuration.hasSensorPMS2 = false;
+
+    // Channel 1 on Serial0
+    int result1 =
+        detectPmOnSerial(Serial0, ag->pms5003t_1, ag->sps30_1, "Serial0");
+    if (result1 == 1) {
+      configuration.hasSensorPMS1 = true;
+    } else if (result1 == 2) {
+      configuration.hasSensorSPS30_1 = true;
     }
 
+    // Channel 2 on Serial1
+    int result2 =
+        detectPmOnSerial(Serial1, ag->pms5003t_2, ag->sps30_2, "Serial1");
+    if (result2 == 1) {
+      configuration.hasSensorPMS2 = true;
+    } else if (result2 == 2) {
+      configuration.hasSensorSPS30_2 = true;
+    }
+
+    // Check if we should downgrade from two-PM to single-PM mode
     if (fwMode == FW_MODE_O_1PP) {
-      int count = (configuration.hasSensorPMS1 ? 1 : 0) + (configuration.hasSensorPMS2 ? 1 : 0);
-      if (count == 1) {
+      bool ch1HasPm =
+          configuration.hasSensorPMS1 || configuration.hasSensorSPS30_1;
+      bool ch2HasPm =
+          configuration.hasSensorPMS2 || configuration.hasSensorSPS30_2;
+      if (ch1HasPm != ch2HasPm) {
         fwMode = FW_MODE_O_1P;
       }
     }
   }
 
-  /** update the PMS poll period base on fw mode and sensor available */
-  if (fwMode != FW_MODE_O_1PST) {
-    if (configuration.hasSensorPMS1 && configuration.hasSensorPMS2) {
+  /** Update the PMS poll period based on fw mode and sensor availability */
+  if (fwMode != FW_MODE_O_1PST && fwMode != FW_MODE_O_1PS) {
+    bool ch1HasPm =
+        configuration.hasSensorPMS1 || configuration.hasSensorSPS30_1;
+    bool ch2HasPm =
+        configuration.hasSensorPMS2 || configuration.hasSensorSPS30_2;
+    if (ch1HasPm && ch2HasPm) {
       pmsSchedule.setPeriod(2000);
     }
   }
@@ -1316,52 +1360,53 @@ static void updatePMS5003() {
   }
 }
 
-static void updateSPS30(void) {
-  if (ag->sps30.readValues()) {
+static void updateSPS30(SPS30 &sensor, int channel) {
+  if (sensor.readValues()) {
     // Mass concentrations — mapped to both Ae and SP (SPS30 has no distinction)
-    measurements.update(Measurements::PM01, ag->sps30.getPm01Ae());
-    measurements.update(Measurements::PM25, ag->sps30.getPm25Ae());
-    measurements.update(Measurements::PM10, ag->sps30.getPm10Ae());
-    measurements.update(Measurements::PM01_SP, ag->sps30.getPm01Sp());
-    measurements.update(Measurements::PM25_SP, ag->sps30.getPm25Sp());
-    measurements.update(Measurements::PM10_SP, ag->sps30.getPm10Sp());
+    measurements.update(Measurements::PM01, sensor.getPm01Ae(), channel);
+    measurements.update(Measurements::PM25, sensor.getPm25Ae(), channel);
+    measurements.update(Measurements::PM10, sensor.getPm10Ae(), channel);
+    measurements.update(Measurements::PM01_SP, sensor.getPm01Sp(), channel);
+    measurements.update(Measurements::PM25_SP, sensor.getPm25Sp(), channel);
+    measurements.update(Measurements::PM10_SP, sensor.getPm10Sp(), channel);
 
     // Number concentrations (already converted to #/0.1L by wrapper)
-    measurements.update(Measurements::PM05_PC, ag->sps30.getPm05ParticleCount());
-    measurements.update(Measurements::PM01_PC, ag->sps30.getPm01ParticleCount());
-    measurements.update(Measurements::PM25_PC, ag->sps30.getPm25ParticleCount());
-    measurements.update(Measurements::PM10_PC, ag->sps30.getPm10ParticleCount());
+    measurements.update(Measurements::PM05_PC, sensor.getPm05ParticleCount(), channel);
+    measurements.update(Measurements::PM01_PC, sensor.getPm01ParticleCount(), channel);
+    measurements.update(Measurements::PM25_PC, sensor.getPm25ParticleCount(), channel);
+    measurements.update(Measurements::PM10_PC, sensor.getPm10ParticleCount(), channel);
   } else {
-    measurements.update(Measurements::PM01, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM25, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM10, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM01_SP, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM25_SP, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM10_SP, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM01_PC, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM25_PC, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM5_PC, utils::getInvalidPmValue());
-    measurements.update(Measurements::PM10_PC, utils::getInvalidPmValue());
+    measurements.update(Measurements::PM01, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM25, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM10, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM01_SP, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM25_SP, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM10_SP, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM01_PC, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM25_PC, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM5_PC, utils::getInvalidPmValue(), channel);
+    measurements.update(Measurements::PM10_PC, utils::getInvalidPmValue(), channel);
   }
 }
 
 static void updatePm(void) {
   if (ag->isOne()) {
-    if (configuration.hasSensorSPS30) {
-      updateSPS30();
+    if (configuration.hasSensorSPS30_1) {
+      updateSPS30(ag->sps30_1, 1);
     } else {
       updatePMS5003();
     }
     return;
   }
 
-  // Open Air Monitor series, can have two PMS5003T sensor
-  bool newPMS1Value = false;
-  bool newPMS2Value = false;
+  // Open Air Monitor series — each channel can be PMS5003T or SPS30.
+  // Track which channels produced valid PMS5003T T/RH for SGP41 compensation.
+  bool newPmsTempHumCh1 = false;
+  bool newPmsTempHumCh2 = false;
 
-  // Read PMS channel 1 if available
-  int channel = 1;
+  // ---- Channel 1 ----
   if (configuration.hasSensorPMS1) {
+    int channel = 1;
     if (ag->pms5003t_1.connected()) {
       measurements.update(Measurements::PM01, ag->pms5003t_1.getPm01Ae(), channel);
       measurements.update(Measurements::PM25, ag->pms5003t_1.getPm25Ae(), channel);
@@ -1375,11 +1420,8 @@ static void updatePm(void) {
       measurements.update(Measurements::PM25_PC, ag->pms5003t_1.getPm25ParticleCount(), channel);
       measurements.update(Measurements::Temperature, ag->pms5003t_1.getTemperature(), channel);
       measurements.update(Measurements::Humidity, ag->pms5003t_1.getRelativeHumidity(), channel);
-
-      // flag that new valid PMS value exists
-      newPMS1Value = true;
+      newPmsTempHumCh1 = true;
     } else {
-      // PMS channel 1 now is not connected, update using invalid value
       measurements.update(Measurements::PM01, utils::getInvalidPmValue(), channel);
       measurements.update(Measurements::PM25, utils::getInvalidPmValue(), channel);
       measurements.update(Measurements::PM10, utils::getInvalidPmValue(), channel);
@@ -1393,11 +1435,13 @@ static void updatePm(void) {
       measurements.update(Measurements::Temperature, utils::getInvalidTemperature(), channel);
       measurements.update(Measurements::Humidity, utils::getInvalidHumidity(), channel);
     }
+  } else if (configuration.hasSensorSPS30_1) {
+    updateSPS30(ag->sps30_1, 1);
   }
 
-  // Read PMS channel 2 if available
-  channel = 2;
+  // ---- Channel 2 ----
   if (configuration.hasSensorPMS2) {
+    int channel = 2;
     if (ag->pms5003t_2.connected()) {
       measurements.update(Measurements::PM01, ag->pms5003t_2.getPm01Ae(), channel);
       measurements.update(Measurements::PM25, ag->pms5003t_2.getPm25Ae(), channel);
@@ -1411,11 +1455,8 @@ static void updatePm(void) {
       measurements.update(Measurements::PM25_PC, ag->pms5003t_2.getPm25ParticleCount(), channel);
       measurements.update(Measurements::Temperature, ag->pms5003t_2.getTemperature(), channel);
       measurements.update(Measurements::Humidity, ag->pms5003t_2.getRelativeHumidity(), channel);
-
-      // flag that new valid PMS value exists
-      newPMS2Value = true;
+      newPmsTempHumCh2 = true;
     } else {
-      // PMS channel 2 now is not connected, update using invalid value
       measurements.update(Measurements::PM01, utils::getInvalidPmValue(), channel);
       measurements.update(Measurements::PM25, utils::getInvalidPmValue(), channel);
       measurements.update(Measurements::PM10, utils::getInvalidPmValue(), channel);
@@ -1429,30 +1470,32 @@ static void updatePm(void) {
       measurements.update(Measurements::Temperature, utils::getInvalidTemperature(), channel);
       measurements.update(Measurements::Humidity, utils::getInvalidHumidity(), channel);
     }
+  } else if (configuration.hasSensorSPS30_2) {
+    updateSPS30(ag->sps30_2, 2);
   }
 
+  // SGP41 compensation — only uses T/RH from PMS5003T channels (SPS30 has no T/RH)
   if (configuration.hasSensorSGP) {
-    float temp, hum;
-    if (newPMS1Value && newPMS2Value) {
-      // Both PMS has new valid value
-      temp = (measurements.getFloat(Measurements::Temperature, 1) +
-              measurements.getFloat(Measurements::Temperature, 2)) /
-             2.0f;
-      hum = (measurements.getFloat(Measurements::Humidity, 1) +
-             measurements.getFloat(Measurements::Humidity, 2)) /
-            2.0f;
-    } else if (newPMS1Value) {
-      // Only PMS1 has new valid value
-      temp = measurements.getFloat(Measurements::Temperature, 1);
-      hum = measurements.getFloat(Measurements::Humidity, 1);
-    } else {
-      // Only PMS2 has new valid value
-      temp = measurements.getFloat(Measurements::Temperature, 2);
-      hum = measurements.getFloat(Measurements::Humidity, 2);
+    if (newPmsTempHumCh1 || newPmsTempHumCh2) {
+      float temp, hum;
+      if (newPmsTempHumCh1 && newPmsTempHumCh2) {
+        temp = (measurements.getFloat(Measurements::Temperature, 1) +
+                measurements.getFloat(Measurements::Temperature, 2)) /
+               2.0f;
+        hum = (measurements.getFloat(Measurements::Humidity, 1) +
+               measurements.getFloat(Measurements::Humidity, 2)) /
+              2.0f;
+      } else if (newPmsTempHumCh1) {
+        temp = measurements.getFloat(Measurements::Temperature, 1);
+        hum = measurements.getFloat(Measurements::Humidity, 1);
+      } else {
+        temp = measurements.getFloat(Measurements::Temperature, 2);
+        hum = measurements.getFloat(Measurements::Humidity, 2);
+      }
+      ag->sgp41.setCompensationTemperatureHumidity(temp, hum);
     }
-
-    // Update compensation temperature and humidity for SGP41
-    ag->sgp41.setCompensationTemperatureHumidity(temp, hum);
+    // When no PMS5003T channel provides T/RH (e.g. 2× SPS30), SGP41 keeps
+    // its previous compensation values (default 25 °C / 50 %RH on first run).
   }
 }
 

examples/OneOpenAir/OpenMetrics.cpp

@@ -77,14 +77,28 @@ String OpenMetrics::getPayload(void) {
   int nox = utils::getInvalidNOx();
   int noxRaw = utils::getInvalidNOx();
 
+  // Convenience flags: does this channel have any PM sensor?
+  bool ch1HasPm = config.hasSensorPMS1 || config.hasSensorSPS30_1;
+  bool ch2HasPm = config.hasSensorPMS2 || config.hasSensorSPS30_2;
+
   // Get values
-  if (config.hasSensorPMS1 && config.hasSensorPMS2) {
-    _temp = (measure.getFloat(Measurements::Temperature, 1) +
-             measure.getFloat(Measurements::Temperature, 2)) /
-            2.0f;
-    _hum = (measure.getFloat(Measurements::Humidity, 1) +
-            measure.getFloat(Measurements::Humidity, 2)) /
-           2.0f;
+  if (ch1HasPm && ch2HasPm) {
+    // Two PM channels — average T/RH only from PMS5003T channels
+    if (config.hasSensorPMS1 && config.hasSensorPMS2) {
+      _temp = (measure.getFloat(Measurements::Temperature, 1) +
+               measure.getFloat(Measurements::Temperature, 2)) /
+              2.0f;
+      _hum = (measure.getFloat(Measurements::Humidity, 1) +
+              measure.getFloat(Measurements::Humidity, 2)) /
+             2.0f;
+    } else if (config.hasSensorPMS1) {
+      _temp = measure.getFloat(Measurements::Temperature, 1);
+      _hum = measure.getFloat(Measurements::Humidity, 1);
+    } else if (config.hasSensorPMS2) {
+      _temp = measure.getFloat(Measurements::Temperature, 2);
+      _hum = measure.getFloat(Measurements::Humidity, 2);
+    }
+    // PM values averaged across both channels regardless of brand
     pm01 = (measure.get(Measurements::PM01, 1) + measure.get(Measurements::PM01, 2)) / 2.0f;
     float correctedPm25_1 = measure.getCorrectedPM25(false, 1);
     float correctedPm25_2 = measure.getCorrectedPM25(false, 2);
@@ -100,7 +114,7 @@ String OpenMetrics::getPayload(void) {
         _hum = measure.getFloat(Measurements::Humidity);
       }
 
-      if (config.hasSensorPMS1) {
+      if (ch1HasPm) {
         pm01 = measure.get(Measurements::PM01);
         float correctedPm = measure.getCorrectedPM25(false, 1);
         pm25 = round(correctedPm);
@@ -108,18 +122,23 @@ String OpenMetrics::getPayload(void) {
         pm03PCount = measure.get(Measurements::PM03_PC);
       }
     } else {
-      if (config.hasSensorPMS1) {
-        _temp = measure.getFloat(Measurements::Temperature, 1);
-        _hum = measure.getFloat(Measurements::Humidity, 1);
+      // Outdoor single-channel: T/RH only from PMS5003T, PM from any sensor
+      if (ch1HasPm) {
+        if (config.hasSensorPMS1) {
+          _temp = measure.getFloat(Measurements::Temperature, 1);
+          _hum = measure.getFloat(Measurements::Humidity, 1);
+        }
         pm01 = measure.get(Measurements::PM01, 1);
         float correctedPm = measure.getCorrectedPM25(false, 1);
         pm25 = round(correctedPm);
         pm10 = measure.get(Measurements::PM10, 1);
         pm03PCount = measure.get(Measurements::PM03_PC, 1);
       }
-      if (config.hasSensorPMS2) {
-        _temp = measure.getFloat(Measurements::Temperature, 2);
-        _hum = measure.getFloat(Measurements::Humidity, 2);
+      if (ch2HasPm) {
+        if (config.hasSensorPMS2) {
+          _temp = measure.getFloat(Measurements::Temperature, 2);
+          _hum = measure.getFloat(Measurements::Humidity, 2);
+        }
         pm01 = measure.get(Measurements::PM01, 2);
         float correctedPm = measure.getCorrectedPM25(false, 2);
         pm25 = round(correctedPm);
@@ -154,7 +173,7 @@ String OpenMetrics::getPayload(void) {
   }
 
   // Add measurements that valid to the metrics
-  if (config.hasSensorPMS1 || config.hasSensorPMS2) {
+  if (ch1HasPm || ch2HasPm) {
     if (utils::isValidPm(pm01)) {
       add_metric("pm1",
                  "PM1.0 concentration as measured by the AirGradient PMS "

src/AgConfigure.cpp

@@ -19,6 +19,7 @@ const char *LED_BAR_MODE_NAMES[] = {
     [LedBarModeOff] = "off",
     [LedBarModePm] = "pm",
     [LedBarModeCO2] = "co2",
+    [LedBarModeIaqs] = "iaqs",
 };
 
 const char *PM_CORRECTION_ALGORITHM_NAMES[] = {
@@ -112,6 +113,8 @@ String Configuration::getLedBarModeName(LedBarMode mode) {
     return String(LED_BAR_MODE_NAMES[LedBarModePm]);
   } else if (mode == LedBarModeCO2) {
     return String(LED_BAR_MODE_NAMES[LedBarModeCO2]);
+  } else if (mode == LedBarModeIaqs) {
+    return String(LED_BAR_MODE_NAMES[LedBarModeIaqs]);
   }
   return String("unknown");
 }
@@ -740,7 +743,8 @@ bool Configuration::parse(String data, bool isLocal) {
     String mode = root[jprop_ledBarMode];
     if (mode == getLedBarModeName(LedBarMode::LedBarModeCO2) ||
         mode == getLedBarModeName(LedBarMode::LedBarModeOff) ||
-        mode == getLedBarModeName(LedBarMode::LedBarModePm)) {
+        mode == getLedBarModeName(LedBarMode::LedBarModePm) ||
+        mode == getLedBarModeName(LedBarMode::LedBarModeIaqs)) {
       String oldMode = jconfig[jprop_ledBarMode];
       if (mode != oldMode) {
         jconfig[jprop_ledBarMode] = mode;
@@ -1190,6 +1194,9 @@ LedBarMode Configuration::getLedBarMode(void) {
   if (mode == getLedBarModeName(LedBarModePm)) {
     return LedBarModePm;
   }
+  if (mode == getLedBarModeName(LedBarModeIaqs)) {
+    return LedBarModeIaqs;
+  }
   return LedBarModeOff;
 }
 
@@ -1398,7 +1405,8 @@ void Configuration::toConfig(const char *buf) {
     String mode = jconfig[jprop_ledBarMode];
     if (mode != getLedBarModeName(LedBarMode::LedBarModeCO2) &&
         mode != getLedBarModeName(LedBarMode::LedBarModeOff) &&
-        mode != getLedBarModeName(LedBarMode::LedBarModePm)) {
+        mode != getLedBarModeName(LedBarMode::LedBarModePm) &&
+        mode != getLedBarModeName(LedBarMode::LedBarModeIaqs)) {
       isConfigFieldInvalid = true;
     } else {
       isConfigFieldInvalid = false;

src/AgConfigure.h

@@ -75,8 +75,10 @@ public:
   bool hasSensorS8 = true;
   bool hasSensorPMS1 = true;
   bool hasSensorPMS2 = true;
-  bool hasSensorSPS30 =
-      false; ///< SPS30 detected as PMS alternative (auto-detect)
+  bool hasSensorSPS30_1 =
+      false; ///< SPS30 detected on PM channel 1 (auto-detect)
+  bool hasSensorSPS30_2 =
+      false; ///< SPS30 detected on PM channel 2 (auto-detect)
   bool hasSensorSGP = true;
   bool hasSensorSHT = true;
 

src/AgOledDisplay.cpp

@@ -1,5 +1,6 @@
 #include "AgOledDisplay.h"
 #include "Libraries/U8g2/src/U8g2lib.h"
+#include "Main/GoIaqs.h"
 #include "Main/utils.h"
 
 /** Cast U8G2 */
@@ -411,28 +412,100 @@ void OledDisplay::showDashboard(DashboardStatus status) {
         DISP()->drawUTF8(55, 61, "ug/m³");
       }
 
-      /** Draw tvocIndexlabel */
-      DISP()->setFont(u8g2_font_t0_12_tf);
-      DISP()->drawStr(100, 27, "VOC:");
+      if (config.getLedBarMode() == LedBarMode::LedBarModeIaqs) {
+        /** Draw IAQS panel (column 3 replaces VOC/NOx when LED bar mode
+         *  is set to iaqs). Three rows aligned with the CO2/PM2.5 column
+         *  rhythm: header (y=27), big score + grade letter (y=48),
+         *  dominant pollutant (y=61). */
+        const int IAQS_COL_X = 100;
+        const int IAQS_COL_W = 28;
+        const int SCORE_GRADE_GAP = 1;
+        const int ARROW_DOM_GAP = 2;
+        const int ARROW_DOM_BOTH_GAP = 1;
+        DISP()->setFont(u8g2_font_t0_12_tf);
+        DISP()->drawStr(IAQS_COL_X, 27, "IAQS");
 
-      /** Draw tvocIndexvalue */
-      int tvoc = round(value.getAverage(Measurements::TVOC));
-      if (utils::isValidVOC(tvoc)) {
-        sprintf(strBuf, "%d", tvoc);
-      } else {
-        sprintf(strBuf, "%s", "-");
-      }
-      DISP()->drawStr(100, 39, strBuf);
+        float pm25Avg = value.getAverage(Measurements::PM25);
+        if (config.hasSensorSHT && config.isPMCorrectionEnabled()) {
+          pm25Avg = value.getCorrectedPM25(true);
+        }
+        float co2Avg = value.getAverage(Measurements::CO2);
+        bool pmOk = utils::isValidPm((int)round(pm25Avg));
+        bool coOk = utils::isValidCO2((int)round(co2Avg));
 
-      /** Draw NOx label */
-      int nox = round(value.getAverage(Measurements::NOx));
-      DISP()->drawStr(100, 53, "NOx:");
-      if (utils::isValidNOx(nox)) {
-        sprintf(strBuf, "%d", nox);
+        if (!pmOk || !coOk) {
+          DISP()->setFont(u8g2_font_t0_22b_tf);
+          int scoreW = DISP()->getStrWidth("-");
+          DISP()->drawStr(IAQS_COL_X + ((IAQS_COL_W - scoreW) / 2), 48, "-");
+        } else {
+          int pmScore = GoIaqs::pm25Score(pm25Avg);
+          int coScore = GoIaqs::co2Score(co2Avg);
+          int totalIaqs = GoIaqs::totalScore(pmScore, coScore);
+          GoIaqs::Category cat = GoIaqs::categoryOf(totalIaqs);
+          GoIaqs::Dominant dom = GoIaqs::dominantOf(pmScore, coScore);
+
+          /** Row 2: big score + letter grade centered in the IAQS column. */
+          sprintf(strBuf, "%d", totalIaqs);
+          DISP()->setFont(u8g2_font_t0_22b_tf);
+          int scoreW = DISP()->getStrWidth(strBuf);
+
+          char gradeStr[2] = {GoIaqs::letterOf(cat), '\0'};
+          DISP()->setFont(u8g2_font_t0_12_tf);
+          int gradeW = DISP()->getStrWidth(gradeStr);
+
+          int scoreX = IAQS_COL_X +
+                       ((IAQS_COL_W - scoreW - SCORE_GRADE_GAP - gradeW) / 2);
+          DISP()->setFont(u8g2_font_t0_22b_tf);
+          DISP()->drawStr(scoreX, 48, strBuf);
+          DISP()->setFont(u8g2_font_t0_12_tf);
+          DISP()->drawStr(scoreX + scoreW + SCORE_GRADE_GAP, 48, gradeStr);
+
+          /** Row 3: dominant pollutant. */
+          const char *domStr = "BOTH";
+          if (dom == GoIaqs::DominantPm25) {
+            domStr = "PM";
+          } else if (dom == GoIaqs::DominantCo2) {
+            domStr = "CO2";
+          }
+          DISP()->setFont(u8g2_font_t0_12_tf);
+          const int ARROW_W = 5;
+          int arrowDomGap = (dom == GoIaqs::DominantBoth) ? ARROW_DOM_BOTH_GAP
+                                                          : ARROW_DOM_GAP;
+          int domW = DISP()->getStrWidth(domStr);
+          int domX = IAQS_COL_X +
+                     ((IAQS_COL_W - ARROW_W - arrowDomGap - domW) / 2);
+          int arrowY = 57;
+          DISP()->drawLine(domX, arrowY, domX + ARROW_W, arrowY);
+          DISP()->drawLine(domX + ARROW_W, arrowY, domX + ARROW_W - 2,
+                           arrowY - 2);
+          DISP()->drawLine(domX + ARROW_W, arrowY, domX + ARROW_W - 2,
+                           arrowY + 2);
+          DISP()->drawStr(domX + ARROW_W + arrowDomGap, 61, domStr);
+        }
       } else {
-        sprintf(strBuf, "%s", "-");
+        /** Draw tvocIndexlabel */
+        DISP()->setFont(u8g2_font_t0_12_tf);
+        DISP()->drawStr(100, 27, "VOC:");
+
+        /** Draw tvocIndexvalue */
+        int tvoc = round(value.getAverage(Measurements::TVOC));
+        if (utils::isValidVOC(tvoc)) {
+          sprintf(strBuf, "%d", tvoc);
+        } else {
+          sprintf(strBuf, "%s", "-");
+        }
+        DISP()->drawStr(100, 39, strBuf);
+
+        /** Draw NOx label */
+        int nox = round(value.getAverage(Measurements::NOx));
+        DISP()->drawStr(100, 53, "NOx:");
+        if (utils::isValidNOx(nox)) {
+          sprintf(strBuf, "%d", nox);
+        } else {
+          sprintf(strBuf, "%s", "-");
+        }
+        DISP()->drawStr(100, 63, strBuf);
       }
-      DISP()->drawStr(100, 63, strBuf);
     } while (DISP()->nextPage());
   } else if (ag->isBasic()) {
     ag->display.clear();

src/AgStateMachine.cpp

@@ -1,5 +1,6 @@
 #include "AgStateMachine.h"
 #include "AgOledDisplay.h"
+#include "Main/GoIaqs.h"
 
 #define LED_TEST_BLINK_DELAY 50   /** ms */
 #define LED_FAST_BLINK_DELAY 250  /** ms */
@@ -62,6 +63,9 @@ bool StateMachine::sensorhandleLeds(void) {
   case LedBarMode::LedBarModePm:
     totalLedUsed = pm25handleLeds();
     break;
+  case LedBarMode::LedBarModeIaqs:
+    totalLedUsed = iaqsHandleLeds();
+    break;
   default:
     ag->ledBar.clear();
     break;
@@ -267,6 +271,54 @@ int StateMachine::pm25handleLeds(void) {
   return totalUsed;
 }
 
+/**
+ * @brief Show GO IAQS Starter Score LED status.
+ *
+ * Computes the score from PM2.5 (corrected when enabled) and CO2 averages,
+ * then lights a number of LEDs (from the right end) proportional to the
+ * severity, all painted with the category color (Good/Moderate/Unhealthy).
+ *
+ * Mapping is 1:1 between LEDs and score: ledsLit = numLeds - totalScore,
+ * so score 10 lights 1 LED (LED 10) and score 0 lights all 11 LEDs.
+ * Connectivity-status overlays (WiFiLost, ServerLost, SensorConfigFailed)
+ * are handled at the dispatcher level for IAQS mode: the entire bar is
+ * turned off and only LED 0 is lit with the notification color, so the
+ * notification is always unambiguous regardless of the IAQS score.
+ *
+ * @return number of LEDs used on the bar.
+ */
+int StateMachine::iaqsHandleLeds(void) {
+  float pm25Value = value.getAverage(Measurements::PM25);
+  if (config.hasSensorSHT && config.isPMCorrectionEnabled()) {
+    pm25Value = value.getCorrectedPM25(true);
+  }
+  float co2Value = value.getAverage(Measurements::CO2);
+
+  int pmScore = GoIaqs::pm25Score(pm25Value);
+  int coScore = GoIaqs::co2Score(co2Value);
+  int total = GoIaqs::totalScore(pmScore, coScore);
+  GoIaqs::Rgb color = GoIaqs::colorOf(GoIaqs::categoryOf(total));
+
+  int numLeds = ag->ledBar.getNumberOfLeds();
+  /** 1:1 LED-per-score mapping: worse score -> more LEDs lit. */
+  int ledsLit = numLeds - total;
+  if (ledsLit < 1) {
+    ledsLit = 1;
+  }
+  if (ledsLit > numLeds) {
+    ledsLit = numLeds;
+  }
+
+  for (int i = 0; i < ledsLit; i++) {
+    ag->ledBar.setColor(color.r, color.g, color.b, numLeds - 1 - i);
+  }
+
+  Serial.printf("GO IAQS = %d [pm25 score %d, co2 score %d, leds %d]\n", total,
+                pmScore, coScore, ledsLit);
+
+  return ledsLit;
+}
+
 void StateMachine::co2Calibration(void) {
   if (config.isCo2CalibrationRequested() && config.hasSensorS8) {
     logInfo("CO2 Calibration");
@@ -764,9 +816,16 @@ void StateMachine::handleLeds(AgStateMachineState state) {
     /** Connection to WiFi network failed credentials incorrect encryption not
      * supported etc. */
     if (ag->isOne()) {
-      bool allUsed = sensorhandleLeds();
-      if (allUsed == false) {
+      if (config.getLedBarMode() == LedBarMode::LedBarModeIaqs) {
+        /** IAQS mode: suppress the score bar so only the notification LED
+         *  is visible. */
+        ag->ledBar.clear();
         ag->ledBar.setColor(255, 0, 0, 0);
+      } else {
+        bool allUsed = sensorhandleLeds();
+        if (allUsed == false) {
+          ag->ledBar.setColor(255, 0, 0, 0);
+        }
       }
     } else {
       ag->statusLed.setOff();
@@ -777,9 +836,14 @@ void StateMachine::handleLeds(AgStateMachineState state) {
     /** Connected to WiFi network but the server cannot be reached through the
      * internet, e.g. blocked by firewall */
     if (ag->isOne()) {
-      bool allUsed = sensorhandleLeds();
-      if (allUsed == false) {
+      if (config.getLedBarMode() == LedBarMode::LedBarModeIaqs) {
+        ag->ledBar.clear();
         ag->ledBar.setColor(233, 183, 54, 0);
+      } else {
+        bool allUsed = sensorhandleLeds();
+        if (allUsed == false) {
+          ag->ledBar.setColor(233, 183, 54, 0);
+        }
       }
     } else {
       ag->statusLed.setOff();
@@ -790,9 +854,14 @@ void StateMachine::handleLeds(AgStateMachineState state) {
     /** Server is reachable but there is some configuration issue to be fixed on
      * the server side */
     if (ag->isOne()) {
-      bool allUsed = sensorhandleLeds();
-      if (allUsed == false) {
+      if (config.getLedBarMode() == LedBarMode::LedBarModeIaqs) {
+        ag->ledBar.clear();
         ag->ledBar.setColor(139, 24, 248, 0);
+      } else {
+        bool allUsed = sensorhandleLeds();
+        if (allUsed == false) {
+          ag->ledBar.setColor(139, 24, 248, 0);
+        }
       }
     } else {
       ag->statusLed.setOff();

src/AgStateMachine.h

@@ -27,6 +27,7 @@ private:
   bool sensorhandleLeds(void);
   int co2handleLeds(void);
   int pm25handleLeds(void);
+  int iaqsHandleLeds(void);
   void co2Calibration(void);
   void ledBarTest(void);
   void ledBarPowerUpTest(void);

src/AgValue.cpp

@@ -125,7 +125,7 @@ void Measurements::printCurrentAverage() {
     }
   }
 
-  if (config.hasSensorPMS1 || config.hasSensorSPS30) {
+  if (config.hasSensorPMS1 || config.hasSensorSPS30_1) {
     printCurrentPMAverage(1);
     if (!config.hasSensorSHT) {
       if (utils::isValidTemperature(_temperature[0].update.avg)) {
@@ -140,7 +140,7 @@ void Measurements::printCurrentAverage() {
       }
     }
   }
-  if (config.hasSensorPMS2) {
+  if (config.hasSensorPMS2 || config.hasSensorSPS30_2) {
     printCurrentPMAverage(2);
     if (!config.hasSensorSHT) {
       if (utils::isValidTemperature(_temperature[1].update.avg)) {
@@ -1161,38 +1161,39 @@ String Measurements::toString(bool localServer, AgFirmwareMode fwMode, int rssi)
 
 JSONVar Measurements::buildOutdoor(bool localServer, AgFirmwareMode fwMode) {
   JSONVar outdoor;
+  bool ch1HasPm = config.hasSensorPMS1 || config.hasSensorSPS30_1;
+  bool ch2HasPm = config.hasSensorPMS2 || config.hasSensorSPS30_2;
+
   if (fwMode == FW_MODE_O_1P || fwMode == FW_MODE_O_1PS || fwMode == FW_MODE_O_1PST) {
-    // buildPMS params:
-    /// Because only have 1 PMS, allCh is set to false
-    /// But enable temp hum from PMS
-    /// compensated values if requested by local server
-    /// Set ch based on hasSensorPMSx
-    if (config.hasSensorPMS1) {
+    // Single PM channel — pick whichever channel is populated
+    // Enable temp/hum from PMS; compensated values if requested by local server
+    if (ch1HasPm) {
       outdoor = buildPMS(1, false, true, localServer);
-      if (!localServer) {
+      // Firmware version only available for PMS5003T
+      if (!localServer && config.hasSensorPMS1) {
         outdoor[json_prop_pmFirmware] =
             pms5003TFirmwareVersion(ag->pms5003t_1.getFirmwareVersion());
       }
-    } else {
+    } else if (ch2HasPm) {
       outdoor = buildPMS(2, false, true, localServer);
-      if (!localServer) {
+      if (!localServer && config.hasSensorPMS2) {
         outdoor[json_prop_pmFirmware] =
             pms5003TFirmwareVersion(ag->pms5003t_2.getFirmwareVersion());
       }
     }
   } else {
-    // FW_MODE_O_1PPT && FW_MODE_O_1PP: Outdoor monitor that have 2 PMS sensor
-    // buildPMS params:
-    /// Have 2 PMS sensor, allCh is set to true (ch params ignored)
-    /// Enable temp hum from PMS
-    /// compensated values if requested by local server
+    // FW_MODE_O_1PPT / FW_MODE_O_1PP: two PM channels, average via allCh
     outdoor = buildPMS(1, true, true, localServer);
-    // PMS5003T version
+    // Per-channel firmware version — only for PMS5003T channels
     if (!localServer) {
-      outdoor["channels"]["1"][json_prop_pmFirmware] =
-          pms5003TFirmwareVersion(ag->pms5003t_1.getFirmwareVersion());
-      outdoor["channels"]["2"][json_prop_pmFirmware] =
-          pms5003TFirmwareVersion(ag->pms5003t_2.getFirmwareVersion());
+      if (config.hasSensorPMS1) {
+        outdoor["channels"]["1"][json_prop_pmFirmware] =
+            pms5003TFirmwareVersion(ag->pms5003t_1.getFirmwareVersion());
+      }
+      if (config.hasSensorPMS2) {
+        outdoor["channels"]["2"][json_prop_pmFirmware] =
+            pms5003TFirmwareVersion(ag->pms5003t_2.getFirmwareVersion());
+      }
     }
   }
 
@@ -1202,7 +1203,7 @@ JSONVar Measurements::buildOutdoor(bool localServer, AgFirmwareMode fwMode) {
 JSONVar Measurements::buildIndoor(bool localServer) {
   JSONVar indoor;
 
-  if (config.hasSensorPMS1 || config.hasSensorSPS30) {
+  if (config.hasSensorPMS1 || config.hasSensorSPS30_1) {
     // buildPMS params:
     /// PMS channel 1 (indoor only have 1 PMS; hence allCh false)
     /// Not include temperature and humidity from PMS sensor
@@ -1210,7 +1211,8 @@ JSONVar Measurements::buildIndoor(bool localServer) {
     indoor = buildPMS(1, false, false, true);
     if (!localServer && config.hasSensorPMS1) {
       // PMS firmware version only available for PMS5003
-      indoor[json_prop_pmFirmware] = this->pms5003FirmwareVersion(ag->pms5003.getFirmwareVersion());
+      indoor[json_prop_pmFirmware] =
+          this->pms5003FirmwareVersion(ag->pms5003.getFirmwareVersion());
     }
   }
 

src/AirGradient.cpp

@@ -6,9 +6,9 @@
 #endif
 
 AirGradient::AirGradient(BoardType type)
-    : pms5003(type), pms5003t_1(type), pms5003t_2(type), sps30(type), s8(type),
-      sgp41(type), display(type), boardType(type), button(type),
-      statusLed(type), ledBar(type), watchdog(type), sht(type) {}
+    : pms5003(type), pms5003t_1(type), pms5003t_2(type), sps30_1(type),
+      sps30_2(type), s8(type), sgp41(type), display(type), boardType(type),
+      button(type), statusLed(type), ledBar(type), watchdog(type), sht(type) {}
 
 /**
  * @brief Get pin number for I2C SDA

src/AirGradient.h

@@ -82,10 +82,16 @@ public:
   PMS5003T pms5003t_2;
 
   /**
-   * @brief Sensirion SPS30 particulate matter sensor (UART).
-   * Used as alternative to PMS5003 on ONE_INDOOR via auto-detection.
+   * @brief Sensirion SPS30 particulate matter sensor (UART), channel 1.
+   * Used as alternative PM sensor via auto-detection on Serial0.
    */
-  SPS30 sps30;
+  SPS30 sps30_1;
+
+  /**
+   * @brief Sensirion SPS30 particulate matter sensor (UART), channel 2.
+   * Used on OPEN_AIR_OUTDOOR when a second SPS30 is detected.
+   */
+  SPS30 sps30_2;
 
   /**
    * @brief SenseAirS8 CO2 sensor

src/App/AppDef.h

@@ -81,6 +81,9 @@ enum LedBarMode {
 
   /** Use LED bar for show CO2 value level */
   LedBarModeCO2,
+
+  /** Use LED bar to show GO IAQS Starter Score (PM2.5 + CO2) */
+  LedBarModeIaqs,
 };
 
 enum ConfigurationControl {

src/Main/GoIaqs.cpp

@@ -0,0 +1,142 @@
+#include "GoIaqs.h"
+
+#include <math.h>
+
+namespace {
+
+struct Anchor {
+  float x;
+  int y;
+};
+
+/** White-paper PM2.5 anchors (ug/m^3, score). */
+const Anchor PM25_ANCHORS[] = {
+    {0.0f, 10}, {10.0f, 8}, {11.0f, 7}, {25.0f, 4}, {26.0f, 3}, {100.0f, 0},
+};
+
+/** White-paper CO2 anchors (ppm, score). */
+const Anchor CO2_ANCHORS[] = {
+    {400.0f, 10}, {800.0f, 8},  {801.0f, 7},
+    {1400.0f, 4}, {1401.0f, 3}, {5000.0f, 0},
+};
+
+const float PM25_MIN = 0.0f;
+const float PM25_MAX = 100.0f;
+const float CO2_MIN = 400.0f;
+const float CO2_MAX = 5000.0f;
+
+inline float clampF(float v, float lo, float hi) {
+  if (v < lo) {
+    return lo;
+  }
+  if (v > hi) {
+    return hi;
+  }
+  return v;
+}
+
+inline int clampI(int v, int lo, int hi) {
+  if (v < lo) {
+    return lo;
+  }
+  if (v > hi) {
+    return hi;
+  }
+  return v;
+}
+
+/** Round-half-up (matching the reference TS implementation). */
+inline int roundHalfUp(float v) { return (int)floorf(v + 0.5f); }
+
+int interpolate(float value, const Anchor *anchors, size_t count) {
+  if (value <= anchors[0].x) {
+    return anchors[0].y;
+  }
+  const Anchor &last = anchors[count - 1];
+  if (value >= last.x) {
+    return last.y;
+  }
+  for (size_t i = 0; i < count - 1; i++) {
+    const Anchor &left = anchors[i];
+    const Anchor &right = anchors[i + 1];
+    if (value <= right.x) {
+      float interp =
+          (float)left.y +
+          ((value - left.x) * (float)(right.y - left.y)) / (right.x - left.x);
+      return clampI(roundHalfUp(interp), GoIaqs::SCORE_MIN, GoIaqs::SCORE_MAX);
+    }
+  }
+  return GoIaqs::SCORE_MIN;
+}
+
+int pollutantScore(float value, float min, float max, const Anchor *anchors,
+                   size_t count) {
+  if (!isfinite(value) || value > max) {
+    return GoIaqs::SCORE_MIN;
+  }
+  return interpolate(clampF(value, min, max), anchors, count);
+}
+
+} // namespace
+
+int GoIaqs::pm25Score(float pm25UgM3) {
+  return pollutantScore(pm25UgM3, PM25_MIN, PM25_MAX, PM25_ANCHORS,
+                        sizeof(PM25_ANCHORS) / sizeof(PM25_ANCHORS[0]));
+}
+
+int GoIaqs::co2Score(float co2Ppm) {
+  return pollutantScore(co2Ppm, CO2_MIN, CO2_MAX, CO2_ANCHORS,
+                        sizeof(CO2_ANCHORS) / sizeof(CO2_ANCHORS[0]));
+}
+
+int GoIaqs::totalScore(int pm25, int co2) {
+  if (pm25 == co2) {
+    if (pm25 <= 7) {
+      int reduced = pm25 - 1;
+      return reduced < SCORE_MIN ? SCORE_MIN : reduced;
+    }
+    return pm25;
+  }
+  return pm25 < co2 ? pm25 : co2;
+}
+
+GoIaqs::Category GoIaqs::categoryOf(int totalScore) {
+  if (totalScore >= 8) {
+    return CategoryGood;
+  }
+  if (totalScore >= 4) {
+    return CategoryModerate;
+  }
+  return CategoryUnhealthy;
+}
+
+GoIaqs::Rgb GoIaqs::colorOf(Category category) {
+  switch (category) {
+  case CategoryGood:
+    return Rgb{0x64, 0x8E, 0xFF};
+  case CategoryModerate:
+    return Rgb{255, 128, 0};
+  case CategoryUnhealthy:
+  default:
+    return Rgb{255, 0, 0};
+  }
+}
+
+GoIaqs::Dominant GoIaqs::dominantOf(int pm25Score, int co2Score) {
+  if (pm25Score == co2Score) {
+    return DominantBoth;
+  }
+  return (pm25Score < co2Score) ? DominantPm25 : DominantCo2;
+}
+
+char GoIaqs::letterOf(Category category) {
+  switch (category) {
+  case CategoryGood:
+    return 'A';
+  case CategoryModerate:
+    return 'B';
+  case CategoryUnhealthy:
+  default:
+    return 'Z';
+  }
+}

src/Main/GoIaqs.h

@@ -0,0 +1,94 @@
+#ifndef _GO_IAQS_H_
+#define _GO_IAQS_H_
+
+#include <stdint.h>
+
+/**
+ * @brief GO IAQS Starter Score implementation.
+ *
+ * Reference:
+ * https://www.airgradient.com/blog/go-iaqs-starter-score-technical-implementation
+ * Attribution: Achim Haug (AirGradient) for GO AQS. License: CC BY-SA 4.0.
+ *
+ * Converts PM2.5 (ug/m^3) and CO2 (ppm) concentrations into an integer
+ * "0..10" total score plus category and category color, using piecewise
+ * linear anchors and the synergetic combination rule defined in the
+ * white paper.
+ *
+ * Pure computation; no Arduino / hardware dependencies.
+ */
+class GoIaqs {
+public:
+  enum Category {
+    CategoryGood = 0,      /** total score 8..10, color #648EFF */
+    CategoryModerate = 1,  /** total score 4..7,  color #FFB000 */
+    CategoryUnhealthy = 2, /** total score 0..3,  color #FF190C */
+  };
+
+  enum Dominant {
+    DominantPm25 = 0, /** PM2.5 has the worse per-pollutant score */
+    DominantCo2 = 1,  /** CO2 has the worse per-pollutant score */
+    DominantBoth = 2, /** PM2.5 and CO2 per-pollutant scores are equal */
+  };
+
+  struct Rgb {
+    uint8_t r;
+    uint8_t g;
+    uint8_t b;
+  };
+
+  /** Score bounds (inclusive). */
+  static const int SCORE_MIN = 0;
+  static const int SCORE_MAX = 10;
+
+  /**
+   * @brief Compute per-pollutant score for PM2.5.
+   *
+   * @param pm25UgM3 PM2.5 concentration in ug/m^3.
+   * @return int in [SCORE_MIN .. SCORE_MAX]
+   */
+  static int pm25Score(float pm25UgM3);
+
+  /**
+   * @brief Compute per-pollutant score for CO2.
+   *
+   * @param co2Ppm CO2 concentration in ppm.
+   * @return int in [SCORE_MIN .. SCORE_MAX]
+   */
+  static int co2Score(float co2Ppm);
+
+  /**
+   * @brief Combine two per-pollutant scores into a single total score
+   * applying the synergetic rule:
+   *  - If scores differ: total = min(pm25, co2).
+   *  - If equal and shared <= 7: total = max(shared - 1, 0).
+   *  - If equal and shared >= 8: total = shared.
+   */
+  static int totalScore(int pm25, int co2);
+
+  /**
+   * @brief Map a total score to a category (Good / Moderate / Unhealthy).
+   */
+  static Category categoryOf(int totalScore);
+
+  /**
+   * @brief Get the RGB color associated with a category, tuned for the
+   * LED bar (may differ from the white-paper hex values to match the
+   * physical LED output).
+   */
+  static Rgb colorOf(Category category);
+
+  /**
+   * @brief Identify the pollutant that drives the total score. The lower
+   * per-pollutant score wins; equal scores return DominantBoth.
+   */
+  static Dominant dominantOf(int pm25Score, int co2Score);
+
+  /**
+   * @brief Get the single-character letter grade for a category, per the
+   * white paper: Good -> 'A', Moderate -> 'B', Unhealthy -> 'Z'.
+   */
+  static char letterOf(Category category);
+};
+
+#endif /** _GO_IAQS_H_ */

src/SPS30/SPS30.cpp

@@ -17,13 +17,33 @@ bool SPS30::begin(HardwareSerial &serial) {
     return true;
   }
 
+  _bsp = getBoardDef(_boardDef);
+  if (_bsp == nullptr) {
+    AgLog("Board [%d] not supported", _boardDef);
+    return false;
+  }
+
   _serial = &serial;
 
   // Fully reset the serial port — it may have been left at 9600 baud
   // with stale buffer data from a failed PMS5003 detection attempt.
   _serial->end();
   delay(100);
-  _serial->begin(115200);
+
+  // Serial0 (UART0) defaults map to the correct PM connector pins.
+  // Serial1 shares the S8 connector pins and needs explicit GPIO mapping,
+  // same as PMS5003T::begin() does.
+#if ARDUINO_USB_CDC_ON_BOOT
+  if (_serial == &Serial0) {
+#else
+  if (_serial == &Serial) {
+#endif
+    _serial->begin(115200);
+  } else {
+    _serial->begin(115200, SERIAL_8N1, _bsp->SenseAirS8.uart_rx_pin,
+                   _bsp->SenseAirS8.uart_tx_pin);
+  }
+
   // Flush any garbage bytes left in the RX buffer
   while (_serial->available()) {
     _serial->read();

src/SPS30/SPS30.h

@@ -107,6 +107,7 @@ private:
   bool _connected = false;
   int _consecutiveErrors = 0;
   BoardType _boardDef;
+  const BoardDef *_bsp = nullptr;
   SensirionUartSps30 _driver;
   HardwareSerial *_serial = nullptr;