Add tool to count flashes of light using the HRM

apps/flashcount/ChangeLog

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+0.01: New App!

apps/flashcount/app-icon.js

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+require("heatshrink").decompress(atob("mEw4UA///x3ygHo8H1Jf8AgILLoALVgoLHggLCqAgJioLIqgLDGQsBqtAioOBqoYFqtUAIMVBY9VqwCBDIIAECYILCHowLBrWVBZFlrWWyptGgtq1WqJYI7GrQLCFxGrBYJHEBQNV1Wv9IEBEocFKIOq//qJAIZEAoNq3/+1QMBHoYYBrQLB1J4GitaEYZfGtfvBYJ3HtWr9WlNY0V1Nr1WlC4xIBrWmBZWVrJGFcYILBZY4LBoILIgoNBEILvHDIQ5BBY4IBBYMBMAwLBBA4LPBRMAKAoLRiALWAGw="))

apps/flashcount/app.js

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+Bangle.loadWidgets();
+Bangle.drawWidgets();
+E.showMessage("Loading...");
+Bangle.setOptions({hrmPollInterval:5});
+Bangle.setHRMPower(1);
+
+function drawCounter() {
+  g.reset().clearRect(0,24,175,90);
+  //g.drawRect(0,24,175,90);
+  g.setFontAlign(0,0).setFontVector(60);
+  g.drawString(count, 88, 60);
+}
+
+function hadPulse() {
+  count++;
+  drawCounter();
+  g.setColor("#f00").fillCircle(156,156,20);
+  setTimeout(function() {
+    g.setColor(g.theme.bg).fillCircle(156,156,20);
+  }, 500);
+}
+
+if (parseFloat(process.env.VERSION.replace("v","0"))<2019) {
+  E.showMessage("You need at least firmware 2v19","Error");
+} else if (Bangle.hrmRd(0)!=33) { // wrong sensor - probably VC31 from original bangle.js 2
+  E.showMessage("This Bangle.js doesn't have a VC31B HRM sensor","Error");
+} else {
+  Bangle.setOptions({hrmGreenAdjust:false, hrmWearDetect:false, hrmPushEnv:true});
+  Bangle.hrmWr(0x10, 197&0xF8 | 4); // just SLOT2
+  Bangle.hrmWr(0x16, 0); // force env to be used as fast as possible
+
+  var samples = 0, samplesHi = 0;
+  var count = 0;
+  {
+    let last = 0;
+    Bangle.on('HRM-env',v => {
+      if (v) {
+        if (!last) hadPulse();
+        samplesHi++;
+      }
+      last = v;
+      samples++;
+    });
+  }
+
+  drawCounter();
+  setInterval(function() {
+    g.reset().clearRect(0,90,175,130);
+    g.setFontAlign(0,0).setFont("6x8:2");
+    g.drawString(samples+" sps", 88, 100);
+    if (samplesHi*5 > samples) {
+      g.setBgColor("#f00").setColor("#fff");
+      g.clearRect(0,110,175,130).drawString("TOO LIGHT",88,120);
+    }
+    samples=0;
+    samplesHi=0;
+    Bangle.setLCDPower(1); // force LCD on!
+  }, 1000);
+}

apps/flashcount/metadata.json

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+{ "id": "flashcount",
+  "name": "Flash Counter",
+  "shortName":"FlashCount",
+  "version":"0.01",
+  "description": "Count flashes/pulses of light using the heart rate monitor. Requires a VC31B HRM sensor, which should be in most watches except those produced for the original KickStarter campaign.",
+  "icon": "app.png",
+  "tags": "",
+  "supports" : ["BANGLEJS2"],
+  "storage": [
+    {"name":"flashcount.app.js","url":"app.js"},
+    {"name":"flashcount.img","url":"app-icon.js","evaluate":true}
+  ]
+}