Merge pull request #9 from gabrielosorio/backlight_dimming

Backlight dimming

wakie.ino

@@ -48,6 +48,9 @@ const char *weekdayNames[7] = {
 bool alarmDeactivated = false;
 
 #define LCD_LED 10
+uint8_t lcdLedState = HIGH;
+int backlightDimTimeout = 6000; // Milliseconds
+unsigned long nextBacklightDimTimestamp = 0;
 
 #define PIEZO 11
 const uint8_t noteBitmapRows = 2;
@@ -68,46 +71,58 @@ void setup() {
 
   pinMode(BUTTON, INPUT);
   pinMode(LCD_LED, OUTPUT);
-  digitalWrite(LCD_LED, HIGH);
+  enableLcdBacklight();
 }
 
 void loop() {
-  tmElements_t tm;
+  readRtc();
 
-  if (RTC.read(tm)) {
-    currentHour = tm.Hour;
-    currentMinute = tm.Minute;
-    currentWeekday = tm.Wday;
-    currentDay = tm.Day;
-    currentMonth = tm.Month;
-    currentYear = tm.Year;
-  } else {
-    Serial.print("[DS1307] Read error!");
-  }
+  handleLcdBacklightDimming();
 
   if (currentMinute != lastMinute) {
     lastMinute = currentMinute;
     renderDisplay();
   }
 
   // Current duration is within the specified alarmMinute
-  if (alarmTimeIsReached(currentHour, currentMinute)) {
+  if (alarmTimeIsReached()) {
     if (!alarmDeactivated) {
       soundAlarm();
     }
   } else {
     // Outside of the alarm window reset the
     // alarmDeactivated check if it's enabled
     if (alarmDeactivated) {
-      Serial.println("Resetting button");
       alarmDeactivated = false;
     }
   }
 }
 
 void buttonInterrupt() {
     Serial.println("Button pressed");
-    alarmDeactivated = true;
+
+    // Use button to deactivate alarm if currently sounding
+    if (alarmTimeIsReached()) {
+      alarmDeactivated = true;
+    } else {
+      // Otherwise use button to toggle backlight on/off
+      toggleLcdBacklight();
+    }
+}
+
+void readRtc() {
+  tmElements_t tm;
+
+  if (RTC.read(tm)) {
+    currentHour = tm.Hour;
+    currentMinute = tm.Minute;
+    currentWeekday = tm.Wday;
+    currentDay = tm.Day;
+    currentMonth = tm.Month;
+    currentYear = tm.Year;
+  } else {
+    Serial.print("[DS1307] Read error!");
+  }
 }
 
 void renderDisplay() {
@@ -161,14 +176,17 @@ void numberToDoubleDigitChar(uint8_t number, char *output) {
   }
 }
 
-bool alarmTimeIsReached(uint8_t hour, uint8_t minute) {
-  if (hour == alarmHour && minute == alarmMinute) {
+bool alarmTimeIsReached() {
+  if (currentHour == alarmHour && currentMinute == alarmMinute) {
     return true;
   }
   return false;
 }
 
 void soundAlarm() {
+  // Keep LCD backlight on during the alarm
+  enableLcdBacklight();
+
   // Go through the note bitmap rows
   for (uint8_t row = 0; row < noteBitmapRows; row++) {
     // Go through the columns in the note bitmap row
@@ -198,3 +216,39 @@ void handleCurrentNoteOff() {
   Serial.println("Note Off");
   delay(noteDuration);
 }
+
+void handleLcdBacklightDimming() {
+  if (lcdBacklightIsOn()) {
+    if (nextBacklightDimTimestamp == 0) {
+      // Arm a timeout to dim the backlight after the set interval
+      nextBacklightDimTimestamp = millis() + backlightDimTimeout;
+    }
+
+    // Check if the backlight timeout was reached
+    if (millis() >= nextBacklightDimTimestamp) {
+      disableLcdBacklight();
+    }
+  } else {
+    // Disarm dimming timeout
+    nextBacklightDimTimestamp = 0;
+  }
+}
+
+bool lcdBacklightIsOn() {
+  return lcdLedState == HIGH;
+}
+
+void enableLcdBacklight() {
+  lcdLedState = HIGH;
+  digitalWrite(LCD_LED, lcdLedState);
+}
+
+void disableLcdBacklight() {
+  lcdLedState = LOW;
+  digitalWrite(LCD_LED, lcdLedState);
+}
+
+void toggleLcdBacklight() {
+  lcdLedState = !lcdLedState;
+  digitalWrite(LCD_LED, lcdLedState);
+}