add a comment about stardate rules

diff --combined js/tricorder.js
index 2574b01f6fb7e334618e130079fa19b991ddb7bc,de33ae3a630e2c2eed70a95e946c314aea24b8fd..dbd188d93bb5ae05ff326113bb7ab5e70f4a9c3d
--- 1/js/tricorder.js
--- 2/js/tricorder.js
+++ b/js/tricorder.js
@@@ -5,6 -5,8 +5,8 @@@
  var gStardate, gSDBase;
  var gSounds = {};
  
+ navigator.getUserMedia = (navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia);
+ 
  window.onload = function() {
    setTimeout(updateStardate, 0);
    gSounds.scan = new Audio("sound/scan.opus");
@@@ -31,21 -33,22 +33,26 @@@
    }, false);
  }
  
+ window.onresize = function() {
+   if (document.getElementById("sectSound").classList.contains("active")) {
+     gModSound.resize();
+   }
+ }
+ 
  function updateStardate() {
 +  // Stardate rules foggy at best. See http://en.wikipedia.org/wiki/Stardate
 +  // and the Memory Alpha article linked there for more details.
 +  // We roughly lean on TNG scale by splitting an Earth year into exactly 1000
 +  // units, but we put the 0 point at the TV premiere of The Original Series.
    if (!gStardate)
      gStardate = document.getElementById("stardate");
  
    var curDate = new Date();
  
+   // Star Trek famously premiered on Thursday, September 8, 1966, at 8:30 p.m.
+   // See http://www.startrek.com/article/what-if-the-original-star-trek-had-debuted-on-friday-nights
    if (!gSDBase)
-     // Star Trek premiered on Thursday, September 8, 1966, at 7:30PM or 8:30PM
-     // depending on time zone in the United States.
-     // See http://www.startrek.com/article/star-trek-and-newspapers-part-2
-     gSDBase = new Date("September 8, 1966 19:30:00 EST");
+     gSDBase = new Date("September 8, 1966 20:30:00 EST");
  
    var sdateval = (curDate - gSDBase) / (86400 * 365.2425);
    gStardate.textContent = sdateval.toFixed(1);
@@@ -221,6 -224,86 +228,86 @@@ var gModGrav = 
    },
  }
  
+ var gModSound = {
+   activate: function() {
+     //gSounds.scan.play();
+     if (navigator.getUserMedia && (window.AudioContext || window.webkitAudioContext)) {
+       document.getElementById("soundunavail").style.display = "none";
+       document.getElementById("soundavail").style.display = "block";
+       navigator.getUserMedia({ audio: true },
+          function(aLocalMediaStream) {
+            gModSound.mAudio.stream = aLocalMediaStream;
+            gModSound.mAudio.context = new (window.AudioContext || window.webkitAudioContext)();
+            gModSound.mAudio.input = gModSound.mAudio.context.createMediaStreamSource(gModSound.mAudio.stream);
+            // Could put a filter in between like in http://webaudioapi.com/samples/microphone/
+            gModSound.mDisplay.canvas = document.getElementById("soundcanvas");
+            gModSound.mDisplay.context = gModSound.mDisplay.canvas.getContext("2d");
+            gModSound.rebuildCanvas();
+          },
+          function(err) {
+            document.getElementById("soundunavail").style.display = "block";
+            document.getElementById("soundavail").style.display = "none";
+            console.log(err);
+          }
+       );
+     }
+     else {
+       document.getElementById("soundunavail").style.display = "block";
+       document.getElementById("soundavail").style.display = "none";
+     }
+   },
+   rebuildCanvas: function() {
+     if (gModSound.mDisplay.AFRequestID) {
+       window.cancelAnimationFrame(gModSound.mDisplay.AFRequestID);
+       gModSound.mDisplay.AFRequestID = 0;
+     }
+     gModSound.mDisplay.canvas.height = document.getElementById("soundavail").clientHeight - 4;
+     gModSound.mDisplay.canvas.width = document.getElementById("soundavail").clientWidth;
+     gModSound.mAudio.frequencySlices = (gModSound.mDisplay.canvas.width > 512) ?
+                                       512 :
+                                       Math.pow(2, Math.floor(Math.log(gModSound.mDisplay.canvas.width) / Math.LN2));
+     //console.log("slices: " + gModSound.mAudio.frequencySlices);
+     gModSound.mAudio.analyzer = gModSound.mAudio.context.createAnalyser();
+     // Make the FFT four times as large as needed as the upper three quarters turn out to be useless.
+     gModSound.mAudio.analyzer.fftSize = gModSound.mAudio.frequencySlices * 4;
+     //console.log("FFT: " + gModSound.mAudio.analyzer.fftSize);
+     gModSound.mAudio.input.connect(gModSound.mAudio.analyzer);
+     gModSound.mDisplay.context.setTransform(1, 0, 0, -(gModSound.mDisplay.canvas.height/256), 0, gModSound.mDisplay.canvas.height);
+     gModSound.mDisplay.active = true;
+     gModSound.mDisplay.AFRequestID = window.requestAnimationFrame(gModSound.paintAnalyzerFrame);
+   },
+   mAudio: {
+     frequencySlices: 32, // Must be a multiple of 2 (see AnalyserNode.fftSize)
+   },
+   mDisplay: {
+     active: false,
+   },
+   paintAnalyzerFrame: function(aTimestamp) {
+     var data = new Uint8Array(gModSound.mAudio.frequencySlices);
+     gModSound.mAudio.analyzer.getByteFrequencyData(data);
+     gModSound.mDisplay.context.clearRect(0, 0, gModSound.mDisplay.canvas.width, gModSound.mDisplay.canvas.height);
+     // Out of experience, only the first half of the slices are actually useful.
+     var wid = gModSound.mDisplay.canvas.width / gModSound.mAudio.frequencySlices;
+     var fill = "#9C9CFF";
+     for (var i = 0; i < gModSound.mAudio.frequencySlices; ++i) {
+       var newFill = (data[i] > 200) ? "#FF0000" : ((data[i] > 100) ? "#FFCF00" : "#9C9CFF");
+       if (fill != newFill) { gModSound.mDisplay.context.fillStyle = newFill; fill = newFill; }
+       gModSound.mDisplay.context.fillRect(i*wid, 0, wid, data[i]);
+     }
+     if (gModSound.mDisplay.active)
+       gModSound.mDisplay.AFRequestID = window.requestAnimationFrame(gModSound.paintAnalyzerFrame);
+   },
+   resize: function() {
+     gModSound.rebuildCanvas();
+   },
+   deactivate: function() {
+     if (gModSound.mDisplay.active) {
+       gModSound.mAudio.stream.stop();
+       gModSound.mDisplay.active = false;
+     }
+     gSounds.scan.pause();
+   },
+ }
  
  var gModDev = {
    activate: function() {
@@@ -259,15 -342,6 +346,6 @@@
    batteryTimer: null,
  }
  
- var gModNull = {
-   activate: function() {
-     //gSounds.scan.play();
-   },
-   deactivate: function() {
-     gSounds.scan.pause();
-   },
- }
- 
  var gModOther = {
    activate: function() {
      //gSounds.scan.play();