Display also humidity and pressure

Display update triggered by value change, not interval

bme280.ino

@@ -1,23 +1,50 @@
 #include "Seeed_BME280.h"
 
+enum {
+  LOWER = 0,
+  HIGHER
+};
+
 BME280 sensor;
-float highTemp = 0.0, lowTemp = 0.0;
-const float blindZone = 0.03;
+float bounds[2][SENSORS] = {};
+const float hysteresisWidth[SENSORS] = {0.03, 0.5, 0.5};
 
 void initBME280() {
   sensor.init();
 }
 
-void readTemperature() {
-  float newTemperature = sensor.getTemperature();
+void readSensors() {
+  float newValue;
 
-  if (newTemperature > highTemp) {
-    temperature = newTemperature;
-    highTemp = newTemperature;
-    lowTemp = highTemp - blindZone;
-  } else if (newTemperature < lowTemp) {
-    temperature = newTemperature;
-    lowTemp = newTemperature;
-    highTemp = lowTemp + blindZone;
+  for (uint i = 0; i < SENSORS; i++) {
+    switch (i) {
+      case TEMPERATURE:
+        newValue = sensor.getTemperature();
+        break;
+
+      case HUMIDITY:
+        newValue = sensor.getHumidity();
+        break;
+
+      case PRESSURE:
+        newValue = sensor.getPressure();
+        break;
+    }
+
+    if (newValue > bounds[HIGHER][i]) {
+      sensorValue[i] = newValue;
+      bounds[HIGHER][i] = newValue;
+      bounds[LOWER][i] = bounds[HIGHER][i] - hysteresisWidth[i];
+      if ((countdown <= 0) && (displaySensor == i)) {
+        displayNeedsUpdate = true;
+      }
+    } else if (newValue < bounds[LOWER][i]) {
+      sensorValue[i] = newValue;
+      bounds[LOWER][i] = newValue;
+      bounds[HIGHER][i] = bounds[LOWER][i] + hysteresisWidth[i];
+      if ((countdown <= 0) && (displaySensor == i)) {
+        displayNeedsUpdate = true;
+      }
+    };
   };
 }

button.ino

@@ -1,6 +1,6 @@
 volatile unsigned long lastButtonPress = millis();
 
-// Debouncing na timerze:
+// Debouncing using timer:
 // https://github.com/khoih-prog/TimerInterrupt/blob/master/examples/SwitchDebounce/SwitchDebounce.ino
 void initButton() {
   pinMode(BUTTON_PIN, INPUT_PULLUP);
@@ -9,17 +9,20 @@ void initButton() {
   attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), buttonISRstate, RISING);  
 }
 
+// FIXME: runMetronome ISR should be started/stopped by button. Otherwise fraction of first PERIOD_MS is lost from countdown.
 void buttonISRstate() {
   if ((millis() - lastButtonPress) > 100) {
     if (countdown < 0)
       // TODO: enable metronome timer
       countdown = 0;
-    else if (countdown == 0)
+    else if (countdown == 0) {
       // TODO: restart metronome timer to align countdown
       countdown = COUNTDOWN;
-    else {
+      updateTube();
+    } else {
       countdown = -1;
       digitalWrite(BUTTON_LED_PIN, LOW);
+      updateTube();
       // TODO: disable metronome timer
     }
   }

metronom.ino

@@ -4,24 +4,52 @@
 SAMDTimer TaskTimer(TIMER_TC3);
 SAMD_ISR_Timer TasksISRs;
 
-void TasksHandler(void) { TasksISRs.run(); }
-
+enum {
+  TEMPERATURE = 0,
+  HUMIDITY,
+  PRESSURE,
+  SENSORS
+};
 
+// COUNTDOWN is effectively multiplied by METRONOME_INTERVAL
 const int COUNTDOWN = 600;
-const int PERIOD_MS = 1000;
-const int BUZZER_FREQ = 300;
+// INTERVALS and TIMESHARES given in [ms]
+const uint TASK_HANDLER_INTERVAL = 20;
+const uint METRONOME_INTERVAL = 1000;
+const uint SENSOR_INTERVAL = 1000;
+const uint SENSOR_TIMESHARE[SENSORS] = {90000, 20000, 10000};
+// FREQUENCY in [Hz]
+const uint BUZZER_FREQ = 300;
 
 const uint BUTTON_PIN = 6;
 const uint BUTTON_LED_PIN = 5;
 const uint BUZZER_PIN = 0;
 
 /* Metronome state is expressed by countdown:
- *  -1 - IDLE
- *   0 - BEATING
- *  >0 - COUNTDOWN
+    -1 - IDLE
+     0 - BEATING
+    >0 - COUNTDOWN
+   Unless metronome is in COUNTDOWN mode, display rotates through sensor readings.
 */
 volatile int countdown = -1;
-volatile float temperature = 0.0;
+// Units: temperature [C], humidity [%], pressure [P]
+volatile float sensorValue[SENSORS] = {};
+volatile uint displaySensor = TEMPERATURE;
+volatile bool displayNeedsUpdate = false;
+volatile bool tubeRotated = false;
+int tubeTimerID;
+
+void TasksHandler(void) {
+  TasksISRs.run();
+
+  if (displayNeedsUpdate || tubeRotated)
+    updateTube();
+
+  if (tubeRotated) {
+    TasksISRs.changeInterval(tubeTimerID, SENSOR_TIMESHARE[displaySensor]);
+    tubeRotated = false;
+  }
+}
 
 void setup() {
   initButton();
@@ -29,11 +57,13 @@ void setup() {
   initBuzzer();
   initTube();
 
-  TaskTimer.attachInterruptInterval_MS(20, TasksHandler);
-  TasksISRs.setInterval(PERIOD_MS, runMetronome);
-  TasksISRs.setInterval(PERIOD_MS, readTemperature);
-  // TODO: move display from ISR to loop()
-  TasksISRs.setInterval(200, updateTube);
+  readSensors();
+  updateTube();
+
+  TaskTimer.attachInterruptInterval_MS(TASK_HANDLER_INTERVAL, TasksHandler);
+  TasksISRs.setInterval(METRONOME_INTERVAL, runMetronome);
+  TasksISRs.setInterval(SENSOR_INTERVAL, readSensors);
+  tubeTimerID = TasksISRs.setInterval(SENSOR_TIMESHARE[displaySensor], rotateTube);
 }
 
 void runMetronome() {
@@ -41,6 +71,8 @@ void runMetronome() {
     countdown -= 1;
 
     digitalWrite(BUTTON_LED_PIN, countdown % 2 ? HIGH : LOW);
+
+    displayNeedsUpdate = true;
   } else if (countdown == 0) {
     TasksISRs.setTimeout(100, noBuzz);
     buzz();

tube.ino

@@ -10,21 +10,42 @@ void initTube() {
   tube.setBlinkRate(BLINK_OFF);
 }
 
+void rotateTube() {
+  displaySensor = (displaySensor + 1) % SENSORS;
+  tubeRotated = true;
+}
+
 void updateTube() {
   char newText[5];
   bool highPoint = false, lowPoint = false;
+  uint value = countdown;
 
   if (countdown <= 0) {
-    sprintf(newText, "%4u", (unsigned int) (temperature * 100.0));
+    switch (displaySensor) {
+      case TEMPERATURE:
+        value = (uint) (sensorValue[TEMPERATURE] * 100);
         lowPoint = true;
-  } else {
-    sprintf(newText, "%4u", countdown);
+        break;
+      case HUMIDITY:
+        // TODO: add % sign?
+        value = (uint) (sensorValue[HUMIDITY]);
+        break;
+      case PRESSURE:
+        value = (uint) (sensorValue[PRESSURE] / 100);
+        break;
     }
+  }
+  sprintf(newText, "%4u", value);
 
+  // TODO: In the current mode of display refresh (displayNeedsUpdate) it should not be necessary to check previous text
+  // Maybe add LED switching for case when the strings match as a rough check before removing comparison?
+  // Or LED switching when display is updated?
   if (strcmp(tubeText, newText)) {
     strcpy(tubeText, newText);
     tube.displayString(tubeText);
     tube.setPoint(highPoint, lowPoint);
     tube.display();
   }
+
+  displayNeedsUpdate = false;
 }