Add dynamic measurement interval for SEN5X

src/modules/Telemetry/AirQualityTelemetry.cpp

@@ -47,6 +47,7 @@ int32_t AirQualityTelemetryModule::runOnce()
     }
 
     uint32_t result = UINT32_MAX;
+    uint32_t sen5xPendingForReady;
 
     /*
         Uncomment the preferences below if you want to use the module
@@ -102,6 +103,14 @@ int32_t AirQualityTelemetryModule::runOnce()
                 return sen5xSensor.wakeUp();
         }
 
+        // Check if sen5x is ready to return data, or if it needs more time because of the low concentration threshold
+        if (sen5xSensor.hasSensor() && sen5xSensor.isActive()) {
+            sen5xPendingForReady = sen5xSensor.pendingForReady();
+            if (sen5xPendingForReady) {
+                return sen5xPendingForReady;
+            }
+        }
+
         if (((lastSentToMesh == 0) ||
             !Throttle::isWithinTimespanMs(lastSentToMesh, Default::getConfiguredOrDefaultMsScaled(
                                                             moduleConfig.telemetry.air_quality_interval,
@@ -118,14 +127,13 @@ int32_t AirQualityTelemetryModule::runOnce()
             lastSentToPhone = millis();
         }
 
-
         // TODO - Add logic here to send the sensor to idle ONLY if there is enough time to wake it up before the next reading cycle
 #ifdef PMSA003I_ENABLE_PIN
         pmsa003iSensor.sleep();
 #endif /* PMSA003I_ENABLE_PIN */
 
-            if (sen5xSensor.hasSensor() && sen5xSensor.isActive())
-                sen5xSensor.idle();
+        if (sen5xSensor.hasSensor() && sen5xSensor.isActive() )
+            sen5xSensor.idle();
     }
     return min(sendToPhoneIntervalMs, result);
 }

src/modules/Telemetry/Sensor/SEN5XSensor.cpp

@@ -570,6 +570,44 @@ uint8_t SEN5XSensor::getMeasurements()
     return 0;
 }
 
+int32_t SEN5XSensor::pendingForReady(){
+    uint32_t now;
+    now = getTime();
+    uint32_t sinceMeasureStarted = (now - measureStarted)*1000;
+    LOG_INFO("Since measure started: %u", sinceMeasureStarted);
+    switch (state) {
+        case SEN5X_MEASUREMENT: {
+
+            if (sinceMeasureStarted < SEN5X_WARMUP_MS_1) {
+                LOG_INFO("SEN5X: not enough time passed since starting measurement");
+                return SEN5X_WARMUP_MS_1 - sinceMeasureStarted;
+            }
+
+            // Get PN values to check if we are above or below threshold
+            readPnValues();
+
+            // If the reading is low (the tyhreshold is in #/cm3) and second warmUp hasn't passed we return to come back later
+            if ((sen5xmeasurement.pN4p0 / 100) < SEN5X_PN4P0_CONC_THD && sinceMeasureStarted < SEN5X_WARMUP_MS_2) {
+                LOG_INFO("SEN5X: Concentration is low, we will ask again in the second warm up period");
+                state = SEN5X_MEASUREMENT_2;
+                // Report how many seconds are pending to cover the first warm up period
+                return SEN5X_WARMUP_MS_2 - sinceMeasureStarted;
+            }
+            return 0;
+        }
+        case SEN5X_MEASUREMENT_2: {
+            if (sinceMeasureStarted < SEN5X_WARMUP_MS_2) {
+                // Report how many seconds are pending to cover the first warm up period
+                return SEN5X_WARMUP_MS_2 - sinceMeasureStarted;
+            }
+            return 0;
+        }
+        default: {
+            return -1;
+        }
+    }
+}
+
 bool SEN5XSensor::getMetrics(meshtastic_Telemetry *measurement)
 {
     LOG_INFO("SEN5X: Attempting to get metrics");

src/modules/Telemetry/Sensor/SEN5XSensor.h

@@ -7,15 +7,12 @@
 #include "Wire.h"
 #include "RTC.h"
 
+// Warm up times for SEN5X from the datasheet
 #ifndef SEN5X_WARMUP_MS_1
-// from the SEN5X datasheet
-// #define SEN5X_WARMUP_MS_1 15000 - Change to this
-#define SEN5X_WARMUP_MS_1 30000
+#define SEN5X_WARMUP_MS_1 15000
 #endif
 
-// TODO - For now, we ignore this threshold, and we only use the MS_1 (to 30000)
 #ifndef SEN5X_WARMUP_MS_2
-// from the SEN5X datasheet
 #define SEN5X_WARMUP_MS_2 30000
 #endif
 
@@ -76,17 +73,10 @@ class SEN5XSensor : public TelemetrySensor
 
     enum SEN5XState { SEN5X_OFF, SEN5X_IDLE, SEN5X_MEASUREMENT, SEN5X_MEASUREMENT_2, SEN5X_CLEANING, SEN5X_NOT_DETECTED };
     SEN5XState state = SEN5X_OFF;
-
+    // TODO - Remove
     bool continousMode = false;
     bool forcedContinousMode = false;
 
-    // TODO
-    // Sensirion recommends taking a reading after 16 seconds, if the Perticle number reading is over 100#/cm3 the reading is OK, but if it is lower wait until 30 seconds and take it again.
-    // https://sensirion.com/resource/application_note/low_power_mode/sen5x
-    // TODO Implement logic for this concentrationThreshold
-    // This can reduce battery consumption by a lot
-    // uint16_t concentrationThreshold = 100;
-
     bool sendCommand(uint16_t wichCommand);
     bool sendCommand(uint16_t wichCommand, uint8_t* buffer, uint8_t byteNumber=0);
     uint8_t readBuffer(uint8_t* buffer, uint8_t byteNumber); // Return number of bytes received
@@ -131,6 +121,12 @@ class SEN5XSensor : public TelemetrySensor
     bool idle();
     virtual int32_t runOnce() override;
     virtual bool getMetrics(meshtastic_Telemetry *measurement) override;
+
+    // Sensirion recommends taking a reading after 15 seconds, if the Particle number reading is over 100#/cm3 the reading is OK, but if it is lower wait until 30 seconds and take it again.
+    // https://sensirion.com/resource/application_note/low_power_mode/sen5x
+    #define SEN5X_PN4P0_CONC_THD 100
+    // This value represents the time needed for pending data
+    int32_t pendingForReady();
 };