Add Bluetooth multimeter support

apps/btmultimeter/ChangeLog

@@ -0,0 +1 @@
+0.01: New App!

apps/btmultimeter/README.md

@@ -0,0 +1,32 @@
+# Bluetooth Multimeter
+
+Connect to compatible a Bluetooth Multimeters and display the result on your wrist!
+
+## Compatible Bluetooth meters
+
+Only the OWON is supported right now - feel free to add support for more!
+
+### OWON OW18E
+
+Available [on Amazon](https://www.amazon.co.uk/Bluetooth-Multimeter-Multimeters-Voltmeter-Resistance/dp/B08NJT38SF/ref=sr_1_1)
+
+Turn the meter on, and long-press the Hz/Duty/Delta/Bluetooth button on the right hand side. Now run the app.
+
+## Usage
+
+The app currently only displays the current reading from the volt meter.
+
+If the app fails to connect you'll need to reload it to reconnect.
+
+To exit the app, long-press the button.
+
+
+## Future functionality...
+
+* Logging
+* Graphs
+* More than one meter
+
+## Creator
+
+Gordon Williams (please file issues via GitHub)

apps/btmultimeter/app-icon.js

@@ -0,0 +1 @@
+require("heatshrink").decompress(atob("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")

apps/btmultimeter/app.js

@@ -0,0 +1,105 @@
+var decoded;
+var gatt;
+
+
+function decode(d) {
+  var value = d.getUint16(4,1);
+  if (value&32768)
+    value = -(value&32767);
+  var flags = d.getUint8(0);
+  var flags2 = d.getUint8(1);
+  // mv dc 27,240     "11xxx"
+  // mv ac 95,240   "1011xxx"
+  // v dc 36,240     "100xxx" 36(2dp) 35(20dp)
+  // v ac 100,240   "1100xxx" 100(2dp) 99(20dp) 97(2000dp)
+  // ohms 55,241     "110xxx"
+  // beep 231,242  "11100xxx"
+  // diode 167,242 "10100xxx"
+  // capac 76,241   "1001xxx"
+  // hz 162,241    "10100xxx"
+  // temp 33,242     "100xxx"
+  // ncv 96,243     "1100xxx"
+  // uA 146,240    "10010xxx"
+  // ma 155,240    "10011xxx"
+  // A 163,240     "10100xxx"
+  var dp = flags&7;
+  var range = (flags>>3)&7;
+  value *= Math.pow(10, -dp);
+  var isAC = !!(flags&64);
+  var mode = "?", units = "";
+  if (flags2==240) {
+    if (flags&128) {
+      mode =  "current";
+      units = ["","nA","uA","mA","A","kA","MA",""][range];
+    } else {
+      mode =  "voltage";
+      units = ["","nV","uV","mV","V","kV","MV",""][range] + " " + (isAC?"AC":"DC");
+    }
+  } else if (flags2==241) {
+    if (isAC) {
+      mode = "capacitance";
+      units = ["","nF","uF","mF","F","kF","MF",""][range];
+    } else if (flags&128) {
+      mode = "frequency";
+      units = "Hz";
+    } else {
+      mode = "resistance";
+      units = ["","nOhm","uOhm","mOhm","Ohm","kOhm","MOhm",""][range];
+    }
+  } else if (flags2==242) {
+    if (flags&128) mode = isAC ? "continuity" : "diode";
+    else {
+      mode = "temperature";
+      units = isAC ? "F" : "C";
+    }
+  } else if (flags2==243) mode = "ncv";
+  //console.log(mode+" "+value+" "+units,new Uint8Array(d.buffer).slice());
+  decoded = {
+    value : value,
+    mode : mode, // current/voltage/capacitance/frequency/resistance/temperature
+    units : units, // eg 'mA'
+    raw : new Uint8Array(d.buffer).slice(),
+  };
+  updateDisplay(decoded);
+}
+
+function updateDisplay(d) {
+  var mode = d.mode;
+  mode = mode.substr(0,1).toUpperCase()+mode.substr(1);
+  var s = d.value.toString();
+
+  var R = Bangle.appRect;
+  g.reset().clearRect(R);
+  g.setFont("12x20").setFontAlign(-1,-1).drawString(mode, R.x, R.y);
+  g.setFont("12x20").setFontAlign(1,1).drawString(d.units, R.x+R.w-1, R.y+R.h-1);
+  var fontSize = 80;
+  g.setFont("Vector",fontSize).setFontAlign(0,0);
+  while (g.stringWidth(s) > R.w-20) {
+    fontSize -= 2;
+    g.setFont("Vector", fontSize);
+  }
+  g.drawString(s, R.x+R.w/2, R.y+R.h/2);
+}
+
+Bangle.loadWidgets();
+Bangle.drawWidgets();
+E.showMessage(/*LANG*/"Connecting...");
+
+NRF.requestDevice({ filters: [{ name: 'BDM' }] }).then(function(device) {
+  return device.gatt.connect();
+}).then(function(g) {
+  gatt = g;
+  return gatt.getPrimaryService(0xFFF0);
+}).then(function(service) {
+  return service.getCharacteristic(0xFFF4);
+}).then(function(c) {
+  c.on('characteristicvaluechanged', function(event) {
+    d = event.target.value;
+    decode(d);
+  });
+  return c.startNotifications();
+}).then(function() {
+  E.showMessage(/*LANG*/"Connected.");
+}).catch(function(e) {
+  E.showMessage(e.toString());
+});

apps/btmultimeter/metadata.json

@@ -0,0 +1,15 @@
+{ "id": "btmultimeter",
+  "name": "Bluetooth Multimeter",
+  "shortName":"BT Meter",
+  "version":"0.01",
+  "description": "Connect to compatible a Bluetooth Multimeters and display the result on your wrist!",
+  "icon": "app.png",
+  "tags": "bluetooth,tool",
+  "screenshots" : [ { "url":"screenshot.png" } ],
+  "supports" : ["BANGLEJS","BANGLEJS2"],
+  "readme": "README.md",
+  "storage": [
+    {"name":"btmultimeter.app.js","url":"app.js"},
+    {"name":"btmultimeter.img","url":"app-icon.js","evaluate":true}
+  ]
+}