app.js

// Run this to receive a png image stream from your drone.

var arDrone = require('ar-drone');
var cv = require('opencv');
var http    = require('http');
var fs = require('fs');

console.log('Connecting png stream ...');

//var stream  = arDrone.createUdpNavdataStream();
var client = arDrone.createClient();
var pngStream = client.getPngStream();
var processingImage = false;
var lastPng;
var navData;
var flying = false;
var startTime = new Date().getTime();
var log = function(s){
var time = ( ( new Date().getTime() - startTime ) / 1000 ).toFixed(2);

  console.log(time+" \t"+s);
}

pngStream
  .on('error', console.log)
  .on('data', function(pngBuffer) {
    console.log("got image");
    lastPng = pngBuffer;
  });
     
  var detectFaces = function(){ 
      if( ! flying ) return;
      if( ( ! processingImage ) && lastPng )
      {
        console.log("yay");
        processingImage = true;
        cv.readImage( lastPng, function(err, im) {
          var opts = {};
          im.detectObject(cv.FACE_CASCADE, opts, function(err, faces) {

            var face;
            var biggestFace;

            for(var k = 0; k < faces.length; k++) {
              face = faces[k];
              
              
              im.ellipse(face.x, face.y, face.width, face.height);
              
              if( !biggestFace || biggestFace.width < face.width ) biggestFace = face;

              //im.rectangle([face.x, face.y], [face.x + face.width, face.y + face.height], [0, 255, 0], 2);
            }
            
            im.save('./out'+Date.now()+'.png'); 

            if( biggestFace ){
              face = biggestFace;
              console.log("GOT A FACE", face.x, face.y, face.width, face.height, im.width(), im.height() );

              face.centerX = face.x + face.width * 0.5;
              face.centerY = face.y + face.height * 0.5;

              var centerX = im.width() * 0.5;
              var centerY = im.height() * 0.5;

              var heightAmount = -( face.centerY - centerY ) / centerY;
              var turnAmount = -( face.centerX - centerX ) / centerX;

              turnAmount = Math.min( 1, turnAmount );
              turnAmount = Math.max( -1, turnAmount );

              log( turnAmount + " " + heightAmount );

              //heightAmount = Math.min( 1, heightAmount );
              //heightAmount = Math.max( -1, heightAmount );
              heightAmount = 0;

              if( Math.abs( turnAmount ) > Math.abs( heightAmount ) ){
                log( "turning "+turnAmount );
                if( turnAmount < 0 ) client.clockwise( Math.abs( turnAmount ) );
                else client.counterClockwise( turnAmount );
                setTimeout(function(){
                    log("stopping turn");
                    client.clockwise(0);
                    //this.stop();
                },100);
              }
              else {
                log( "going vertical "+heightAmount );
                if(  heightAmount < 0 ) client.down( heightAmount );
                else client.up( heightAmount );
                setTimeout(function(){
                  log("stopping altitude change");
                  
                  client.up(0);

                },50);

              }

            }

          processingImage = false;
          //im.save('/tmp/salida.png');

        }, opts.scale, opts.neighbors
          , opts.min && opts.min[0], opts.min && opts.min[1]);
        
      });
    };
  };

var faceInterval = setInterval( detectFaces, 150);

var fly = false;
if(fly){
  client.takeoff();
  client.after(5000,function(){ 
    log("going up");
    this.up(1);
  }).after(1000,function(){ 
    log("stopping");
    this.stop(); 
    flying = true;
  }).after(60000, function() {
    flying = false;
    this.stop();
    this.land();
  });
}else{
  flying = true;
}

client.on('navdata', function(navdata) {
  navData = navdata;
});

(function(){
  var http = require('http');
  http.createServer(function(req, res) {
    if (!lastPng) {
      res.writeHead(503);
      res.end('Did not receive any png data yet.');
      return;
    }
    
    res.writeHead(200, {'Content-Type': 'image/png'});
    res.end(lastPng);
  }).listen(1338, '127.0.0.1');
  console.log('Server running at http://127.0.0.1:1338/');
})();