Add voltage/temp display and voltage checking

client.js

@@ -3,6 +3,7 @@ let stations = {};
 let messages = [];
 
 const timeoutLength = 20 * 60 * 1000; // 20 Minutes
+const lowVoltage = 11.9;
 
 Notification.requestPermission(permission => {
   if (permission === "granted") {
@@ -15,7 +16,9 @@ function redrawTable() {
   table.innerHTML =
     `<tr><th>Callsign</th>` +
     `<th>Last Heard</th>` +
-    `<th>Time since Last Heard</th>`;
+    `<th>Time since Last Heard</th>` +
+    `<th>Last Voltage</th>` +
+    `<th>Last Temperature</th>`;
   for (let callsign in stations) {
     let station = stations[callsign];
     let nowDelta = new Date(new Date() - station.lastHeard);
@@ -24,10 +27,16 @@ function redrawTable() {
     if (nowDelta.getTime() > timeoutLength) {
       tr.classList.add('timedOut');
     }
+    if (station.lastVoltage < lowVoltage) {
+      tr.classList.add('lowVoltage');
+    }
     tr.innerHTML =
       `<td>${callsign}</td>` +
       `<td>${station.lastHeard.toLocaleTimeString('en-GB')}</td>` +
-      `<td>${nowDelta.toLocaleTimeString('en-GB', {timeZone: "UTC"})}</td>`;
+      `<td>${nowDelta.toLocaleTimeString('en-GB', {timeZone: "UTC"})}</td>` +
+      `<td>${station.lastVoltage||''}</td>` +
+      `<td>${station.lastTemperature||''}</td>`;
+
   }
 }
 
@@ -36,6 +45,11 @@ function alertNotHeard(callsign) {
                    {body: `Last Heard: ${stations[callsign].lastHeard.toLocaleTimeString('en-GB')}`});
 }
 
+function alertVoltage(callsign) {
+  new Notification(`${callsign}'s battery has dropepd below ${lowVoltage}V`,
+                   {body: `Voltage: ${stations[callsign].lastVoltage}`});
+}
+
 let aprsStream = new WebSocket("ws://localhost:1234");
 aprsStream.onmessage = function(event) {
   let message = JSON.parse(event.data);
@@ -59,6 +73,15 @@ aprsStream.onmessage = function(event) {
   stations[callsign].timeout = window.setTimeout(
     alertNotHeard, timeoutLength, callsign);
 
+  if ('data' in message && 'analog' in message.data) {
+    stations[callsign].lastVoltage = message.data.analog[0] / 10;
+    stations[callsign].lastTemperature = message.data.analog[1];
+
+    if (stations[callsign].lastVoltage <= lowVoltage) {
+      alertVoltage(callsign);
+    }
+  }
+
   redrawTable();
 };