pachacamac/clap.html

## clap.html
<html>
<head>
  <title>AudioPlayground</title>
  <style>* {box-sizing: border-box;}</style>
</head>
<body>
  <h3>AudioPlayground</h3>
  <p>If you're happy and you know it, clap your hands!</p>
  <script>
    var Recording = function(cb){
      var recorder = null;
      var recording = true;
      var audioInput = null;
      var volume = null;
      var audioContext = null;
      var callback = cb;

      navigator.getUserMedia = navigator.getUserMedia    || navigator.webkitGetUserMedia ||
                               navigator.mozGetUserMedia || navigator.msGetUserMedia;

      if(navigator.getUserMedia){
        navigator.getUserMedia({audio:true},
          function(e){ //success
            var AudioContext = window.AudioContext || window.webkitAudioContext;
            audioContext = new AudioContext();
            volume = audioContext.createGain(); // creates a gain node
            audioInput = audioContext.createMediaStreamSource(e); // creates an audio node from the mic stream
            audioInput.connect(volume);// connect the stream to the gain node
            recorder = audioContext.createScriptProcessor(2048, 1, 1);

            recorder.onaudioprocess = function(e){
                if(!recording) return;
                var left = e.inputBuffer.getChannelData(0);
                //var right = e.inputBuffer.getChannelData(1);
                callback(new Float32Array(left));
            };
            volume.connect(recorder);// connect the recorder
            recorder.connect(audioContext.destination);
          },
          function(e){ //failure
            alert('Error capturing audio.');
          }
        );
      } else {
        alert('getUserMedia not supported in this browser.');
      }
    };

    var lastClap = (new Date()).getTime();

    function detectClap(data){
      var t = (new Date()).getTime();
      if(t - lastClap < 200) return false; // TWEAK HERE
      var zeroCrossings = 0, highAmp = 0;
      for(var i = 1; i < data.length; i++){
        if(Math.abs(data[i]) > 0.25) highAmp++; // TWEAK HERE
        if(data[i] > 0 && data[i-1] < 0 || data[i] < 0 && data[i-1] > 0) zeroCrossings++;
      }
      if(highAmp > 20 && zeroCrossings > 30){ // TWEAK HERE
        //console.log(highAmp+' / '+zeroCrossings);
        lastClap = t;
        return true;
      }
      return false;
    }

    var rec = new Recording(function(data){
      if(detectClap(data)){
        console.log('clap!');
        document.bgColor = 'rgb('+Math.random()*255+','+Math.random()*255+','+Math.random()*255+')';
      }
    });
  </script>
</body>
</html>
	<html>
	<head>
	<title>AudioPlayground</title>
	<style>* {box-sizing: border-box;}</style>
	</head>
	<body>
	<h3>AudioPlayground</h3>
	<p>If you're happy and you know it, clap your hands!</p>
	<script>
	var Recording = function(cb){
	var recorder = null;
	var recording = true;
	var audioInput = null;
	var volume = null;
	var audioContext = null;
	var callback = cb;

	navigator.getUserMedia = navigator.getUserMedia \|\| navigator.webkitGetUserMedia \|\|
	navigator.mozGetUserMedia \|\| navigator.msGetUserMedia;

	if(navigator.getUserMedia){
	navigator.getUserMedia({audio:true},
	function(e){ //success
	var AudioContext = window.AudioContext \|\| window.webkitAudioContext;
	audioContext = new AudioContext();
	volume = audioContext.createGain(); // creates a gain node
	audioInput = audioContext.createMediaStreamSource(e); // creates an audio node from the mic stream
	audioInput.connect(volume);// connect the stream to the gain node
	recorder = audioContext.createScriptProcessor(2048, 1, 1);

	recorder.onaudioprocess = function(e){
	if(!recording) return;
	var left = e.inputBuffer.getChannelData(0);
	//var right = e.inputBuffer.getChannelData(1);
	callback(new Float32Array(left));
	};
	volume.connect(recorder);// connect the recorder
	recorder.connect(audioContext.destination);
	},
	function(e){ //failure
	alert('Error capturing audio.');
	}
	);
	} else {
	alert('getUserMedia not supported in this browser.');
	}
	};

	var lastClap = (new Date()).getTime();

	function detectClap(data){
	var t = (new Date()).getTime();
	if(t - lastClap < 200) return false; // TWEAK HERE
	var zeroCrossings = 0, highAmp = 0;
	for(var i = 1; i < data.length; i++){
	if(Math.abs(data[i]) > 0.25) highAmp++; // TWEAK HERE
	if(data[i] > 0 && data[i-1] < 0 \|\| data[i] < 0 && data[i-1] > 0) zeroCrossings++;
	}
	if(highAmp > 20 && zeroCrossings > 30){ // TWEAK HERE
	//console.log(highAmp+' / '+zeroCrossings);
	lastClap = t;
	return true;
	}
	return false;
	}

	var rec = new Recording(function(data){
	if(detectClap(data)){
	console.log('clap!');
	document.bgColor = 'rgb('+Math.random()255+','+Math.random()255+','+Math.random()*255+')';
	}
	});
	</script>
	</body>
	</html>