an ar drone client from nodeconf2013

drone-client.js

var arDrone = require('ar-drone')
  , client = arDrone.createClient()
  , stdin = process.openStdin()
  , isAirborne
  , speedFactor = 5
  , speeds = {
    x: 0,
    y: 0,
    z: 0
  }

/*
// i wired up and arduino and used a potentiometer to control steering (x-axis). while cool, i felt i had less control.
// i also had a button on the board that controlled takeoff and landing
var five = require('johnny-five')
  , board, button, pot

board = new five.Board();

board.on('ready', function() {
  button = new five.Button(8);
  pot = new five.Sensor({
    pin: "A3",
    freq: 250
  });

  pot.on('read', function (err, value) {
    var potValue = (value * 200 / 1023) - 100;
    if (potValue >= 0) {
      speeds.x = potValue;
      if (isAirborne)
        Left();
    }
    else {
      speeds.x = potValue;
      if (isAirborne)
        Right();
    }
  });

  button.on('down', function() {
    if (!isAirborne) Takeoff();
    else SafeLanding();
  });
});
*/

stdin.setRawMode(true);
stdin.setEncoding('utf8');

stdin.on('data', function(key) {
  switch (key) {
    case '\u0003': // ctrl+c
      SafeQuit();
    break;
    case 'j':
      FlipLeft();
    break;
    case 'k':
      YawShake();
    break;
    case 'z':
      Stop();
    break;
    case 'x':
      SafeLanding();
    break;
    case 'c':
      Takeoff();
    break;
    case 'w':
      Forward();
    break;
    case 's':
      Backwards();
    break;
    case 'a':
      Left();
    break;
    case 'd':
      Right();
    break;
    case 'r':
      Up();
    break;
    case 'f':
      Down();
    break;
  }
});

function FlipLeft() {
  console.log('flipping!');
  client.animate('flipLeft', 500);
}

function YawShake() {
  console.log('shake that yaw!');
  client.animate('yawShake', 2000);
}

function addSpeed (direction, cb) {
  if (speeds[direction] + speedFactor <= 100) {
    speeds[direction] += speedFactor;
    return cb(true);
  }
  else return cb(false);
}

function subSpeed (direction, cb) {
  if (speeds[direction] - speedFactor >= -100) {
    speeds[direction] -= speedFactor;
    return cb(true);
  }
  return cb(false);
}

function MoveZ() {
  if (speeds.z < 0) {
    console.log('going DOWN!: ' + speeds.z);
    client.down(Math.abs(speeds.z / 100));
  }
  else {
    console.log('going UP!: ' + speeds.z);
    client.up(speeds.z / 100);
  }
}

function MoveX () {
  if (speeds.x < 0) {
    console.log('turning LEFT!: ' + speeds.x);
    client.counterClockwise(Math.abs(speeds.x / 100));
  }
  else {
    console.log('turning RIGHT!: ' + speeds.x);
    client.clockwise(speeds.x / 100)
  }
}

function MoveY () {
  if (speeds.y < 0) {
    console.log('moving BACK!: ' + speeds.y);
    client.back(Math.abs(speeds.y / 100));
  }
  else {
    console.log('moving FORWARD!: ' + speeds.y);
    client.front(speeds.y / 100)
  }
}

function Left() {
  subSpeed('x', function(success) {
    MoveX();
  });
}

function Right() {
  addSpeed('x', function(success) {
    MoveX();
  });
}

function Forward() {
  addSpeed('y', function(success) {
    MoveY();
  });
}

function Backwards() {
  subSpeed('y', function(success) {
    MoveY();
  });
}

function Up() {
  addSpeed('z', function(success) {
    MoveZ();
  });
}

function Down() {
  subSpeed('z', function(success) {
    MoveZ();
  });
}

function Takeoff() {
  console.log('Taking off!');
  isAirborne = true;
  client.takeoff();
}

function Stop() {
  console.log('Stopping');
  speeds = {
    x: 0,
    y: 0,
    z: 0
  }
  client.stop();
}

function SafeQuit () {
  SafeLanding(function(success) {
    if (success) { console.log('Safely landed. Exiting.'); }
    process.exit();
  });
}

function SafeLanding (cb) {
  if (!cb) cb = function(){};
  console.log('Attempting to land.');
  var landing = client.land();
  isAirborne = false;
  return cb(landing);
}