I think it works? Maybe?

static/index.html

@@ -24,22 +24,21 @@
           <div class="mdl-layout-spacer"></div>
           <!-- Navigation -->
           <nav class="mdl-navigation">
-            <a class="mdl-navigation__link" href="">Link</a>
+            <a class="mdl-navigation__link" href="https://github.com/nealey/vail">Source Code</a>
-            <a class="mdl-navigation__link" href="">Link</a>
+            <a class="mdl-navigation__link" href="https://github.com/nealey/vail/issues/new">Bug Report</a>
-            <a class="mdl-navigation__link" href="">Link</a>
-            <a class="mdl-navigation__link" href="">Link</a>
           </nav>
         </div>
       </header>
+      
       <div class="mdl-layout__drawer">
-        <span class="mdl-layout-title">Title</span>
+        <span class="mdl-layout-title">Repeaters</span>
         <nav class="mdl-navigation">
-          <a class="mdl-navigation__link" href="">Link</a>
+          <a class="mdl-navigation__link" href="?repeater=">1-15 WPM</a>
-          <a class="mdl-navigation__link" href="">Link</a>
+          <a class="mdl-navigation__link" href="?repeater=int">16-20 WPM</a>
-          <a class="mdl-navigation__link" href="">Link</a>
+          <a class="mdl-navigation__link" href="?repeater=adv">21-99 WPM</a>
-          <a class="mdl-navigation__link" href="">Link</a>
         </nav>
       </div>
+      
       <main class="mdl-layout__content">
         <div class="flex">
           <div class="mdl-card mdl-shadow--4dp">
@@ -54,12 +53,23 @@
                 <a href="#iambic" class="mdl-tabs__tab">Iambic</a>
               </div>
               <div class="mdl-tabs__panel is-active" id="straight">
+                <table class="center wide">
+                  <tr>
+                    <td>
                       <button id="key" class="key mdl-button mdl-js-button mdl-button--raised mdl-button--colored">
                         Key
                       </button>
+                    </td>
+                  </tr>
+                  <tr>
+                    <td>
+                      <code>⇧</code>
+                    </td>
+                  </tr>
+                </table>
               </div>
               <div class="mdl-tabs__panel" id="iambic">
-                <table style="width: 100%; text-align: center;">
+                <table class="center wide">
                   <tr>
                     <td>
                       <button id="dit" class="key mdl-button mdl-js-button mdl-button--raised mdl-button--colored">
@@ -74,15 +84,68 @@
                   </tr>
                   <tr>
                     <td>
-                      <code>.</code> or <code>⇧</code>
+                      <code>.</code> or <code>z</code>
                     </td>
                     <td>
-                      <code>/</code> or <code>z</code>
+                      <code>/</code> or <code>x</code>
                     </td>
                   </tr>
                 </table>
+              </div>
+            </div>
+          </div>
+
+          <div class="mdl-card mdl-shadow--4dp">
+            <div class="mdl-card__title">
+              <h2 class="mdl-card__title-text">
+                Knobs
+              </h2>
+            </div>
+            <div class="mdl-card__supporting-text">
+              <table>
+                <tbody>
+                  <tr>
+                    <td>
+                      Average round-trip time:
+                    </td>
+                    <td>
+                      <output id="lag-value">0</output>ms
+                    </td>
+                  </tr>
+                  <tr>
+                    <td>
+                      Longest recent transmission:
+                    </td>
+                    <td>
+                      <output id="longest-rx-value">0</output>ms
+                    </td>
+                  </tr>
+                  <tr>
+                    <td>
+                      Suggested receive delay:
+                    </td>
+                    <td>
+                      <output id="suggested-delay-value">0</output>ms
+                    </td>
+                  </tr>
+                  <tr>
+                  </tr>
+                </tbody>
+              </table>
+              <hr>
               <p>
-                  Dit length:
+                Recieve delay:
+                <output id="rx-delay-value"></output>ms
+                <input
+                  id="rx-delay"
+                  class="mdl-slider mdl-js-slider"
+                  type="range"
+                  min="0"
+                  max="5000"
+                  value="300">
+              </p>
+              <p>
+                Dit length (iambic):
                 <output id="iambic-duration-value"></output>ms
                 <input
                   id="iambic-duration"
@@ -94,7 +157,6 @@
               </p>
             </div>
           </div>
-          </div>
   
           <div class="mdl-card mdl-shadow--4dp">
             <div class="mdl-card__title">
@@ -125,32 +187,39 @@
                 Just like a radio repeater,
                 anybody can connect and start transmitting stuff,
                 and this will broadcast it to everyone connected.
-                If there's enough interest,
-                I'll add something like channels.
               </p>
 
-              <p>
+              <h3 class="mdl-card__title-text">Why Does This Exist?</h3>
-                If you need this to work on a cell phone,
-                let me know and I'll come up with something for you.
-              </p>
-            </div>
-          </div>
               
-          <div class="mdl-card mdl-shadow--4dp">
-            <div class="mdl-card__title">
-              <h2 class="mdl-card__title-text">
-                Why Does This Exist?
-              </h2>
-            </div>
-            <div class="mdl-card__supporting-text">
               <p>
                 I need a place to practice CW with actual human beings,
                 and I want it to be as close as possible to what I'd experience on a radio.
                 Also, I don't want to make people buy a bunch of radio hardware.
                 Nothing else like this exists on the Internet, as far as I can tell.
               </p>
+            </div>
+          </div>
   
-              <h3>Who made it?</h3>
+          <div class="mdl-card mdl-shadow--4dp">
+            <div class="mdl-card__title">
+              <h2 class="mdl-card__title-text">Future plans</h2>
+            </div>
+            <div class="mdl-card__supporting-text">
+              <ul>
+                <li>Move to a more permanent URL</li>
+                <li>Make this page less ugly</li>
+                <li>Arduino program to let you hook up an iambic paddle over USB</li>
+                <li>Document the protocol</li>
+                <li>Support multiple channels/frequencies</li>
+              </ul>
+        
+        
+              <h3 class="mdl-card__title-text">How can I help?</h3>
+        
+              <ul>
+                <li>Improve the <a href="https://github.com/nealey/vail/">source code</a></li>
+                <li>Email me and let me know you're using it</li>
+              </ul>
               
               <p>
                 <a href="mailto:neale@woozle.org">Neale Pickett</a> kd7oqi
@@ -158,31 +227,6 @@
         
             </div>
           </div>
-  
-          <div class="mdl-card mdl-shadow--4dp">
-            <div class="mdl-card__title">
-              <h3 class="mdl-card__title-text">Future plans</h3>
-            </div>
-            <div class="mdl-card__supporting_text">
-              <ul>
-                <li>Move to a more permanent URL</li>
-                <li>Make this page less ugly</li>
-                <li>Arduino program to let you hook up an iambic paddle over USB</li>
-                <li>Document the protocol</li>
-                <li>Support multiple channels/frequencies</li>
-                <li>Sensible way to make this work on a cell phone</li>
-                <li>Make this page less ugly (I really hate it right now)</li>
-              </ul>
-        
-        
-              <h3>How can I help?</h3>
-        
-              <ul>
-                <li>Improve the <a href="https://github.com/nealey/vail/">source code</a></li>
-                <li><a href="mailto:neale@woozle.org">Email me</a> and let me know you're using it</li>
-              </ul>
-            </div>
-          </div>
         </div>
       </main>
     </div>

static/vail.css

@@ -14,6 +14,14 @@
   height: 6em;
 }
 
+.center {
+  text-align: center;
+}
+
+.wide {
+  width: 100%;
+}
+
 code {
   background-color: #333;
   color: #fff;

static/vail.js

@@ -2,6 +2,7 @@
 
 const lowFreq = 660
 const highFreq = lowFreq * 6 / 5 // Perfect minor third
+const errorFreq = 30
 
 const DIT = 1
 const DAH = 3
@@ -91,26 +92,26 @@ class Buzzer {
   // in order to avoid "pops" (square wave overtones)
   // that happen with instant changes in gain.
   
-  constructor(txGain=0.5) {
+  constructor(txGain=0.3) {
     this.txGain = txGain
     
     this.ac = new AudioContext()
     
-    this.lowGain = this.ac.createGain()
+    this.lowGain = this.create(lowFreq)
-    this.lowGain.connect(this.ac.destination)
+    this.highGain = this.create(highFreq)
-    this.lowGain.gain.value = 0
+    this.errorGain = this.create(errorFreq, "square")
-    this.lowOsc = this.ac.createOscillator()
+  }
-    this.lowOsc.connect(this.lowGain)
-    this.lowOsc.frequency.value = lowFreq
-    this.lowOsc.start()
   
-    this.highGain = this.ac.createGain()
+  create(frequency, type="sine") {
-    this.highGain.connect(this.ac.destination)
+    let gain = this.ac.createGain()
-    this.highGain.gain.value = 0
+    gain.connect(this.ac.destination)
-    this.highOsc = this.ac.createOscillator()
+    gain.gain.value = 0
-    this.highOsc.connect(this.highGain)
+    let osc = this.ac.createOscillator()
-    this.highOsc.frequency.value = highFreq
+    osc.type = type
-    this.highOsc.start()
+    osc.connect(gain)
+    osc.frequency.value = frequency
+    osc.start()
+    return gain
   }
   
   gain(high) {
@@ -145,6 +146,14 @@ class Buzzer {
     this.txGain = gain
   }
 
+  /**
+   * Play an error tone
+   */
+  ErrorTone() {
+    this.errorGain.gain.setTargetAtTime(this.txGain * 0.5, this.ac.currentTime, 0.001)
+    this.errorGain.gain.setTargetAtTime(0, this.ac.currentTime + 0.2, 0.001)
+  }
+
   /**
    * Begin buzzing at time
    *
@@ -187,6 +196,10 @@ class Buzzer {
 
 class Vail {
   constructor() {
+    this.sent = []
+    this.lagTimes = [0]
+    this.rxDurations = [0]
+    this.rxDelay = 0 // Milliseconds to add to incoming timestamps
     this.beginTxTime = null // Time when we began transmitting
 
     // Set up WebSocket
@@ -194,7 +207,7 @@ class Vail {
     wsUrl.protocol = "ws:"
     wsUrl.pathname += "chat"
     window.socket = new WebSocket(wsUrl)
-    window.socket.addEventListener("message", this.wsMessage)
+    window.socket.addEventListener("message", e => this.wsMessage(e))
   
     // Listen to HTML buttons
     for (let e of document.querySelectorAll("button.key")) {
@@ -213,6 +226,7 @@ class Vail {
 
     // Listen for slider values
     this.inputInit("#iambic-duration", e => this.iambic.SetInterval(e.target.value))
+    this.inputInit("#rx-delay", e => {this.rxDelay = e.target.value})
   }
   
   inputInit(selector, func) {
@@ -241,17 +255,69 @@ class Vail {
     let endTxTime = Date.now()
     let duration = endTxTime - this.beginTxTime
     this.buzzer.Silence(true)
+    this.wsSend(this.beginTxTime, duration)
+    this.beginTxTime = null
+  }
   
-    let msg = JSON.stringify([this.beginTxTime, duration])
+  updateReading(selector, value) {
-    window.socket.send(msg)
+    let e = document.querySelector(selector)
+    if (e) {
+      e.value = value
+    }
+  }
+  
+  updateReadings() {
+    let avgLag = this.lagTimes.reduce((a,b) => (a+b)) / this.lagTimes.length
+    let longestRx = this.rxDurations.reduce(Math.max)
+    let suggestedDelay = (avgLag + longestRx) * 1.2
+    
+    this.updateReading("#lag-value", avgLag.toFixed())
+    this.updateReading("#longest-rx-value", longestRx)
+    this.updateReading("#suggested-delay-value", suggestedDelay.toFixed())
+  }
+  
+  addLagReading(duration) {
+    this.lagTimes.push(duration)
+    if (this.lagTimes.length > 20) {
+      this.lagTimes.shift()
+    }
+    this.updateReadings()
+  }
+  
+  addRxDuration(duration) {
+    this.rxDurations.push(duration)
+    if (this.rxDurations.length > 20) {
+      this.rxDurations.shift()
+    }
+    this.updateReadings()
+  }
+  
+  wsSend(time, duration) {
+    let msg = [time, duration]
+    let jmsg = JSON.stringify(msg)
+    window.socket.send(jmsg)
+    this.sent.push(jmsg)
   }
   
   wsMessage(event) {
-    let msg = JSON.parse(event.data)
+    let jmsg = event.data
+    let msg = JSON.parse(jmsg)
     let beginTxTime = msg[0]
     let duration = msg[1]
 
-    console.log(msg)
+    let sent = this.sent.filter(e => e != jmsg)
+    if (sent.length < this.sent.length) {
+      // We're getting our own message back, which tells us our lag.
+      // We shouldn't emit a tone, though.
+      this.sent = sent
+      this.addLagReading(Date.now() - beginTxTime - duration)
+      return
+    }
+    
+    // Beep!
+    this.buzzer.BuzzDuration(false, beginTxTime+this.rxDelay, duration)
+    
+    this.addRxDuration(duration)
   }
 
   key(event) {
@@ -262,11 +328,11 @@ class Vail {
     
     let begin = event.type.endsWith("down")
   
-    if ((event.code == "Period") || (event.key == "KeyZ")) {
+    if ((event.code == "KeyZ") || (event.code == "Period")) {
       event.preventDefault()
       this.iambic.Key(begin, DIT)
     }
-    if ((event.code == "Slash") || (event.code == "KeyX")) {
+    if ((event.code == "KeyX") || (event.code == "Slash")) {
       event.preventDefault()
       this.iambic.Key(begin, DAH)
     }