cube with MPU6050 to switch by pitch and roll

Oh man mpu.getRotation() was the right one ;)
Now I get left and right rotation depending on cube side (up, down, left, right, ...)

var mpu;
var alpha = 0.5;
var fXRot = 0;
var fYRot = 0;
var fZRot = 0;
var roll = 0;
var direction = -1;
var rotation = 0;
var maxAccThreshold = 15000;
var maxRotThreshold = 15000;

// helper function to map one range to another
// e.g.
// var value = 5;
// var newValue = map(value, [0,10], [0,20]);
// > newValue = 10
function map(value, srcRange, dstRange){
  if (value < srcRange[0] || value > srcRange[1]){
    return NaN; 
  }
  var srcMax = srcRange[1] - srcRange[0],
      dstMax = dstRange[1] - dstRange[0],
      adjValue = value - srcRange[0];
  return (adjValue * dstMax / srcMax) + dstRange[0];
}

// get -1 or 1 for each value depending on the acceleration reach the threshold
function getDirectionByAccelerationThreshold(xzzAcc) {
  var xyzAccDir = [0,0,0];
  var index = 0;
  xzzAcc.forEach(function(xyzValue) {
    if (xyzValue < -maxAccThreshold)
      xyzAccDir[index] = -1;
    if (xyzValue > maxAccThreshold)
      xyzAccDir[index] = 1;    
    index++;
  });
  return xyzAccDir;
}

// get direction (up,down,left,right,back,front) by xyz
function getDirection(xyzAcc) {
  var newDirection = -1;
  var xAcc = xyzAcc[0];
  var yAcc = xyzAcc[1];
  var zAcc = xyzAcc[2];
  if (zAcc === 1)       newDirection = 0;
  else if (zAcc === -1) newDirection = 1;
  else if (yAcc ===  1) newDirection = 2;
  else if (yAcc === -1) newDirection = 3;
  else if (xAcc ===  1) newDirection = 4;
  else if (xAcc === -1) newDirection = 5;
  return newDirection;
}

// get rotation (left: -1, right: 1) by up,down,left,right,back,front
function getRotationByDirection(xyzRot, dir) {
  var newRotation = 0;
  var xRot = xyzRot[0];
  var yRot = xyzRot[1];
  var zRot = xyzRot[2];  
  switch(dir) {
    case 0: /*up*/    newRotation = -zRot; break;
    case 1: /*down*/  newRotation = zRot;  break;
    case 2: /*left*/  newRotation = -yRot; break;
    case 3: /*right*/ newRotation = yRot;  break;
    case 4: /*back*/  newRotation = -xRot; break;
    case 5: /*front*/ newRotation = xRot;  break;
    default: console.log("cube direction: undefined"); break;
  }
  return newRotation;
}

// get -1 or 1 for each value depending on the rotation reach the threshold
function getDirectionByRotationThreshold(xzzRot) {
  var xyzRotDir = [0,0,0];
  var index = 0;
  xzzRot.forEach(function(xyzValue) {
    if (xyzValue < -maxRotThreshold)
      xyzRotDir[index] = -1;
    if (xyzValue > maxRotThreshold)
      xyzRotDir[index] = 1;    
    index++;
  });
  return xyzRotDir;
}

// print cube direction log
function printDirectionLog(dir) {
  switch(dir) {
    case 0:  console.log("cube side: up");        break;
    case 1:  console.log("cube side: down");      break;
    case 2:  console.log("cube side: left");      break;
    case 3:  console.log("cube side: right");     break;
    case 4:  console.log("cube side: back");      break;
    case 5:  console.log("cube side: front");     break;
    default: console.log("cube side: undefined"); break;
  }
}

// read accelerations and get direction
function readMPU6050() {
  var xzzAcceleration = mpu.getAcceleration();
  
  // get direction (-1 or 1) for each value (x/y/z)
  var xyzAccDirection = getDirectionByAccelerationThreshold(xzzAcceleration);
  // get sum of all acceleration values
  var sumAcc = Math.abs(xyzAccDirection[0])+Math.abs(xyzAccDirection[1])+Math.abs(xyzAccDirection[2]);
  if (sumAcc != 1)
    return;
  
  // get new direction (x/y/z is -1 or 1)
  var newDirection = getDirection(xyzAccDirection);
  // skip if direction did not change
  //if (direction == newDirection)
  //  return;
  // remember new direction and print log
  if (direction != newDirection)
    printDirectionLog(newDirection);
  direction = newDirection;
  
  // get rotation of x/y/z 
  var xytRotation = mpu.getRotation();
  //low pass filter
  fXRot = xytRotation[0] * alpha + (fXRot * (1.0 - alpha));
  fYRot = xytRotation[1] * alpha + (fYRot * (1.0 - alpha));
  fZRot = xytRotation[2] * alpha + (fZRot * (1.0 - alpha));
  var xyzRotationSmooth = [fXRot, fYRot, fZRot];

  // get direction (-1 or 1) for each value (x/y/z)
  var xyzRotDirection = getDirectionByRotationThreshold(xyzRotationSmooth);
  
  // get sum of all rotation values
  var sumRot = Math.abs(xyzRotDirection[0])+Math.abs(xyzRotDirection[1]) +Math.abs(xyzRotDirection[2]);
  if (sumRot != 1)
    return;
  
  // get rotation direction (left/right) by direction (up,down,left,front,...)
  // left: -1, right: 1)
  var newRotation = getRotationByDirection(xyzRotDirection, direction);
  
  // remember new rotation and print log
  //if (rotation != newRotation)
    print("rotation: "+(newRotation === -1 ? "left" : "right"));
  rotation = newRotation;  
}

// init the module and start interval
function onInit() {
  I2C2.setup({scl:B10,sda:B3});
  mpu = require("MPU6050").connect(I2C2);
  setInterval(readMPU6050, 100);
}

onInit();

And here is the output:

 _____                 _
|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v79.171 Copyright 2015 G.Williams
>echo(0);
=undefined
cube side: right
rotation: right
cube side: up
rotation: right
cube side: right
rotation: right
cube side: down
rotation: right
rotation: right
rotation: right
cube side: up
rotation: right
rotation: left
rotation: left
rotation: right
rotation: left
rotation: right
rotation: right
rotation: right
rotation: left
rotation: left
rotation: right
rotation: right
cube side: down
rotation: left
rotation: left
cube side: up
rotation: left
rotation: left
rotation: right
cube side: left
cube side: up
cube side: right
rotation: right
cube side: down
rotation: right
rotation: right
cube side: left
cube side: down
rotation: left
rotation: right
rotation: left
rotation: left
rotation: right
rotation: right
rotation: right
rotation: right
cube side: front
rotation: right
rotation: right
cube side: up
rotation: right
cube side: front
rotation: right
rotation: right
rotation: left
rotation: left
rotation: left
rotation: right
rotation: right
rotation: left
rotation: left
cube side: right
rotation: left
rotation: right
rotation: right
cube side: down
cube side: right
rotation: right
rotation: right
cube side: down
rotation: right
rotation: right
cube side: left
rotation: right
rotation: right
rotation: left
rotation: right
rotation: right
cube side: front
rotation: right
rotation: right
rotation: right
rotation: left
rotation: left
cube side: down
cube side: right
rotation: right
cube side: up
cube side: right
rotation: right