Fix to use less resources when not needed.

apps/rclock/rclock.app.js

@@ -8,10 +8,10 @@
   var _12hour = (require("Storage").readJSON("setting.json", 1) || {})["12hour"] || false;
 
   //HR variables
-  var color="#FF0000";
-  var id=0;
-  var size=10;
-  var grow=true;
+  var color = "#FF0000";
+  var id = 0;
+  var size = 10;
+  var grow = true;
 
   const screen = {
     width: g.getWidth(),
@@ -50,7 +50,7 @@
       color: '#333333',
       size: 10,
       x: screen.center,
-      y: screen.middle+45
+      y: screen.middle + 45
     }
   };
 
@@ -167,12 +167,7 @@
     g.drawString(date, settings.date.center, settings.date.middle);
   };
 
-  Bangle.on('lcdPower', function (on) {
-    if (on) drawClock();
-  });
-
-
-//setInterval for HR visualisation
+   //setInterval for HR visualisation
   const newBeats = function (hr) {
     if (id != 0) {
       changeInterval(id, 6e3 / hr.bpm);
@@ -181,7 +176,7 @@
     }
   };
 
-//visualize HR with circles pulsating
+  //visualize HR with circles pulsating
   const drawHR = function (hr) {
     if (grow && size < settings.hr.size) {
       size++;
@@ -204,7 +199,6 @@
       g.setColor(color);
       g.drawCircle(settings.hr.x, settings.hr.y, size);
     }
-    print(size);
   };
 
   // clean app screen
@@ -213,10 +207,24 @@
   Bangle.loadWidgets();
   Bangle.drawWidgets();
 
-  // refesh every 30 sec
+//manage when things should be enabled and not
+  Bangle.on('lcdPower', function (on) {
+    if (on) {
+      setInterval(drawClock, 1E3);
+      Bangle.setHRMPower(1);
+      Bangle.on('HRM', function (d) {
+        newBeats(d);
+      }); 
+    } else {
+      clearInterval();
+      Bangle.setHRMPower(0);
+    }
+  });
+
+  // refesh every second
   setInterval(drawClock, 1E3);
 
-  //start HR monitor and draw heart rate
+  //start HR monitor and update frequency of update
   Bangle.setHRMPower(1);
   Bangle.on('HRM', function (d) {
     newBeats(d);