Heart Rate measurements regularly every 60 seconds

src/heartratetask/HeartRateTask.cpp

@@ -6,12 +6,13 @@
 using namespace Pinetime::Applications;
 
 HeartRateTask::HeartRateTask(Drivers::Hrs3300& heartRateSensor, Controllers::HeartRateController& controller)
-  : heartRateSensor {heartRateSensor}, controller {controller}, ppg{} {
+  : heartRateSensor {heartRateSensor}, controller {controller}, ppg {} {
 }
 
 void HeartRateTask::Start() {
   messageQueue = xQueueCreate(10, 1);
   controller.SetHeartRateTask(this);
+  lastRegularMeasurementTick = xTaskGetTickCount();
 
   if (pdPASS != xTaskCreate(HeartRateTask::Process, "Heartrate", 500, this, 0, &taskHandle))
     APP_ERROR_HANDLER(NRF_ERROR_NO_MEM);
@@ -27,42 +28,73 @@ void HeartRateTask::Work() {
   while (true) {
     Messages msg;
     uint32_t delay;
-    if (state == States::Running) {
-      if (measurementStarted)
+    if (state == States::Running || regularMeasurementStarted) {
+      if (measurementStarted) {
         delay = 40;
-      else
+      } else {
         delay = 100;
-    } else
+      }
+    } else {
       delay = portMAX_DELAY;
-
+    }
     if (xQueueReceive(messageQueue, &msg, delay)) {
       switch (msg) {
         case Messages::GoToSleep:
+          // we don't want the regular measurement to stop if the watch goes to sleep, although we do want it to stop if it was
+          // started by a user, to save power
+          if (regularMeasurementStarted) {
+            break;
+          }
           StopMeasurement();
           state = States::Idle;
           break;
         case Messages::WakeUp:
           state = States::Running;
-          if (measurementStarted) {
+          // if the user started a measurement it was paused by GoToSleep so needs to be started again. If there is a regular Measurement
+          // it was never stopped and must not be started again (as that would all currently collected data)
+          if (userStartedMeasurement && !regularMeasurementStarted) {
             lastBpm = 0;
             StartMeasurement();
           }
           break;
         case Messages::StartMeasurement:
-          if (measurementStarted)
+          if (measurementStarted) {
+            // the user started a measurement
+            userStartedMeasurement = true;
             break;
+          }
           lastBpm = 0;
           StartMeasurement();
           measurementStarted = true;
           break;
         case Messages::StopMeasurement:
-          if (!measurementStarted)
-            break;
-          StopMeasurement();
+          if (measurementStarted) {
+            StopMeasurement();
+          }
+
+          // if the user stops a measurement manually the regular measurement is cancelled as well
+          // keeping the sensor on even after pressing the stop button could be confusing (although it turns on a tenth of a second later
+          // again anyway)
           measurementStarted = false;
+          userStartedMeasurement = false;
+          regularMeasurementStarted = false;
           break;
       }
     }
+    // compare if a Measurement should be started
+    if (
+      // if the variable is set to zero the feature is disabled and no measurement is supposed to be started
+      regularMeasurmentWait != 0 &&
+      // check if enough seconds have passed since the last measurement
+      ((xTaskGetTickCount() - lastRegularMeasurementTick) / configTICK_RATE_HZ) > regularMeasurmentWait && !regularMeasurementStarted) {
+      regularMeasurementStarted = true;
+      // if there currently is a measurement it must not be started again, as that would invalidate all currently collected data
+      if (!measurementStarted) {
+        lastBpm = 0;
+        StartMeasurement();
+        measurementStarted = true;
+      }
+    }
 
     if (measurementStarted) {
       ppg.Preprocess(static_cast<float>(heartRateSensor.ReadHrs()));
@@ -72,7 +104,17 @@ void HeartRateTask::Work() {
         controller.Update(Controllers::HeartRateController::States::NotEnoughData, 0);
       if (bpm != 0) {
         lastBpm = bpm;
+        // this method handles a ble service as well, so nothing has to be done with the collected heart rate
         controller.Update(Controllers::HeartRateController::States::Running, lastBpm);
+        if (regularMeasurementStarted) {
+          regularMeasurementStarted = false;
+          lastRegularMeasurementTick = xTaskGetTickCount();
+          // we only want to turn the sensor off, if the user isn't currently manually measuring the heart rate
+          if (!userStartedMeasurement) {
+            StopMeasurement();
+            measurementStarted = false;
+          }
+        }
       }
     }
   }

src/heartratetask/HeartRateTask.h

@@ -33,7 +33,16 @@ namespace Pinetime {
       Drivers::Hrs3300& heartRateSensor;
       Controllers::HeartRateController& controller;
       Controllers::Ppg ppg;
+      // did the user manually start a measurement?
+      bool userStartedMeasurement = false;
+      // is there any measurement started?
       bool measurementStarted = false;
+      // is there a regular measurement running atm?
+      bool regularMeasurementStarted = false;
+      // last time a measurement was done (in tickks)
+      uint32_t lastRegularMeasurementTick;
+      // time to wait between measurements (in seconds)
+      const uint8_t regularMeasurmentWait = 60;
     };
 
   }