New app "OpenWind"

apps/openwind/ChangeLog

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+0.01: New App!

apps/openwind/README.md

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+# OpenWind
+
+Receive and display data from a wireless [OpenWind](https://www.openwind.de/) sailing wind instrument on the Bangle.
+
+## Usage
+
+Upon startup, the app will attempt to automatically connect to the wind instrument. This typically only takes a few seconds.
+
+## Features
+
+The app displays the apparent wind direction (via a green dot) and speed (green numbers, in knots) relative to the mounting direction of the wind vane.
+If "True wind" is enabled in settings and a GPS fix is available, the true wind speed and direction (relative to the mounting direction of the vane) is
+additionally displayed in red.  In this mode, the speed over ground in knots is also shown at the bottom left of the screen.
+
+## Controls
+
+There are no controls in the main app, but there are two settings in the settings app that can be changed:
+
+ * True wind: enables or disables true wind calculations; enabling this will turn on GPS inside the app
+ * Mounting angle: mounting relative to the boat of the wind instrument (in degrees)
+
+![](openwind_screenshot.png)

apps/openwind/app-icon.js

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+require("heatshrink").decompress(atob("mEwxH+AH4A/AH4A/AH4A/AH4A/AH4AzhMJF94wtF+QwsF/4APnAACF54wZFoYxNF7guHGBQv0GCwuJGBIvFACov/AD4vvd6Yv/GCoumGIwtpAH4A/AH4A/AH4A/AH4A/AH4A/AH4A/AHoA=="))

apps/openwind/app.js

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+OW_CHAR_UUID = '0000cc91-0000-1000-8000-00805f9b34fb';
+require("Font7x11Numeric7Seg").add(Graphics);
+gatt = {};
+cx = g.getWidth()/2;
+cy = 24+(g.getHeight()-24)/2;
+w = (g.getWidth()-24)/2;
+
+gps_course = { spd: 0 };
+
+var settings = require("Storage").readJSON('openwindsettings.json', 1) || {};
+
+i = 0;
+hullpoly = [];
+for (y=-1; y<=1; y+=0.1) {
+  hullpoly[i++] = cx - (y<0 ? 1+y*0.15 : (Math.sqrt(1-0.7*y*y)-Math.sqrt(0.3))/(1-Math.sqrt(0.3)))*w*0.3;
+  hullpoly[i++] = cy - y*w*0.7;
+}
+for (y=1; y>=-1; y-=0.1) {
+  hullpoly[i++] = cx + (y<0 ? 1+y*0.15 : (Math.sqrt(1-0.7*y*y)-Math.sqrt(0.3))/(1-Math.sqrt(0.3)))*w*0.3;
+  hullpoly[i++] = cy - y*w*0.7;
+}
+
+function wind_updated(ev) {
+  if (ev.target.uuid == "0xcc91") {
+    awa = settings.mount_angle-ev.target.value.getInt16(1, true)*0.1;
+    aws = ev.target.value.getInt16(3, true)*0.01;
+//    console.log(awa, aws);
+    if (gps_course.spd > 0) {
+      wv = { // wind vector (in fixed reference frame)
+        lon: Math.sin(Math.PI*(gps_course.course+awa)/180)*aws,
+        lat: Math.cos(Math.PI*(gps_course.course+awa)/180)*aws
+      };
+      twv = { lon: wv.lon+gps_course.lon, lat: wv.lat+gps_course.lat  };
+      tws = Math.sqrt(Math.pow(twv.lon,2)+Math.pow(twv.lat, 2));
+      twa = Math.atan2(twv.lat, twv.lon)*180/Math.PI-gps_course.course;
+      if (twa<0) twa += 360;
+      if (twa>360) twa -=360;
+    }
+    else { 
+      tws = -1;
+      twa = 0;
+    }
+    draw_compass(awa,aws,twa,tws);
+  }
+}
+
+function draw_compass(awa, aws, twa, tws) {
+  g.clearRect(0, 24, g.getWidth()-1, g.getHeight()-1);
+  fh = w*0.15;
+  g.setColor(0, 0, 1).fillPoly(hullpoly);
+  g.setFontVector(fh).setColor(1, 1, 1);
+  g.setFontAlign(0, 0, 0).drawString("0", cx, 24+fh/2);
+  g.setFontAlign(0, 0, 1).drawString("90", g.getWidth()-12-fh, cy);
+  g.setFontAlign(0, 0, 2).drawString("180", cx, g.getHeight()-fh/2);
+  g.setFontAlign(0, 0, 3).drawString("270", 12+fh/2, cy);
+  for (i=0; i<4; ++i) {
+    a = i*Math.PI/2+Math.PI/4;
+    g.drawLineAA(cx+Math.cos(a)*w*0.85, cy+Math.sin(a)*w*0.85, cx+Math.cos(a)*w*0.99, cy+Math.sin(a)*w*0.99);
+  }
+  g.setColor(0, 1, 0).fillCircle(cx+Math.sin(Math.PI*awa/180)*w*0.9, cy+Math.cos(Math.PI*awa/180)*w*0.9, w*0.1);
+  if (tws>0) g.setColor(1, 0, 0).fillCircle(cx+Math.sin(Math.PI*twa/180)*w*0.9, cy+Math.cos(Math.PI*twa/180)*w*0.9, w*0.1);
+  g.setColor(0, 1, 0).setFont("7x11Numeric7Seg",w*0.06);
+  g.setFontAlign(0, 0, 0).drawString(aws.toFixed(1), cx, cy-0.32*w);
+  if (tws>0) g.setColor(1, 0, 0).drawString(tws.toFixed(1), cx, cy+0.32*w);
+  if (settings.truewind && typeof gps_course.spd!=='undefined') {
+    spd = gps_course.spd/1.852;
+    g.setColor(1, 1, 1).setFont("7x11Numeric7Seg", w*0.03).setFontAlign(-1, 1, 0).drawString(spd.toFixed(1), 1, g.getHeight()-1);
+  }
+}
+
+function parseDevice(d) {
+  device = d;
+  console.log("Found device");
+ device.gatt.connect().then(function(ga) {
+  console.log("Connected");
+   gatt = ga;
+  return ga.getPrimaryService("cc90");
+}).then(function(s) {
+  return s.getCharacteristic("cc91");
+}).then(function(c) {
+  c.on('characteristicvaluechanged', (event)=>wind_updated(event));
+  return c.startNotifications();
+}).then(function() {
+  console.log("Done!");
+}).catch(function(e) {
+  console.log("ERROR"+e);
+});}
+
+function connection_setup() {
+  NRF.setScan();
+  NRF.setScan(parseDevice, { filters: [{services:["cc90"]}], timeout: 2000});
+  console.log("Scanning for OW sensor");
+}
+
+if (settings.truewind) {
+  Bangle.on('GPS',function(fix) {
+    if (fix.fix && fix.satellites>3 && fix.speed>2) { // only uses fixes w/ more than 3 sats and speed > 2kph
+      gps_course = 
+        { lon: Math.sin(Math.PI*fix.course/180)*fix.speed/1.852,
+          lat: Math.cos(Math.PI*fix.course/180)*fix.speed/1.852,
+          spd: fix.speed,
+          course: fix.course
+        };
+    }
+    else gps_course.spd = -1;
+  });
+  Bangle.setGPSPower(1, "app");
+}
+
+Bangle.loadWidgets();
+Bangle.drawWidgets();
+draw_compass(0, 0, 0, 0);
+connection_setup();

apps/openwind/metadata.json

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+{ "id": "openwind",
+  "name": "OpenWind",
+  "shortName":"OpenWind",
+  "version":"0.01",
+  "description": "OpenWind",
+  "icon": "openwind.png",
+  "readme": "README.md",
+  "tags": "ble,sailing",
+  "supports" : ["BANGLEJS", "BANGLEJS2"],  
+  "storage": [
+    {"name":"openwind.app.js","url":"app.js"},
+    {"name":"openwind.img","url":"app-icon.js","evaluate":true},
+    {"name":"openwind.settings.js", "url":"settings.js"}
+  ]
+}

apps/openwind/settings.js

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+// This file should contain exactly one function, which shows the app's settings
+/**
+ * @param {function} back Use back() to return to settings menu
+ */
+(function(back) {
+  const SETTINGS_FILE = 'openwindsettings.json'
+  // initialize with default settings...
+  let s = {
+    'truewind': false,
+    'mount_angle': 0
+  }
+  // ...and overwrite them with any saved values
+  // This way saved values are preserved if a new version adds more settings
+  const storage = require('Storage')
+  const saved = storage.readJSON(SETTINGS_FILE, 1) || {}
+  for (const key in saved) {
+    s[key] = saved[key];
+  }
+  // creates a function to safe a specific setting, e.g.  save('color')(1)
+  function save(key) {
+    return function (value) {
+      s[key] = value;
+      storage.write(SETTINGS_FILE, s);
+    }
+  }
+  const menu = {
+    '': { 'title': 'OpenWind' },
+    '< Back': back,
+    'True wind': {
+      value: s.truewind,
+      format: boolFormat,
+      onchange: save('truewind'),
+    },
+    'Mounting angle': {
+      value: s.mount_angle
+      min: 0,
+      max: 355,
+      step: 5,
+      onchange: save('mount_angle'),
+    }
+  }
+  E.showMenu(menu);
+})