The Useless Box - a box that turns itself off

The Useless Box is a box with a button on it. When you press it, a hand pops out of a trapdoor and turns the button off. The box we've made uses an articulated arm made by taping two servo motors end to end - as well as a pushbutton and light rather than a toggle switch.

In order to move the arm in a controlled way, we have an array of positions for the two servos. When the button is pressed, the 'pos' variable increments and interpolates positions for the two servos from the array.

Wiring Up

Source Code

var inAnim = false;
var pos = 0;
var anim = [
//[pointer, arm],
[1,0],  // folded away
[0.9,0.0], // touching the lid
[0.8,0.05], // push up
[0.7,0.2],
[0.6,0.3],
[0.5,0.5],
[0.3,0.7],
[0.1,1],  
[0.25,1], // press   
[0,1],  
[0.3,0.7],
[1,0],
];

var lastPress = 0;
function onPress(e) {
  if (e.time < lastPress + 0.5) return;
  lastPress = e.time;
  if (inAnim) {
    C6.reset(); // light off
  } else { 
    // startanim
    C6.set(); // light on
    inAnim = true;
    pos = 0;
    print("interval "+setInterval(onAnimStep, 25));
  }
}

function onAnimStep() {
  pos += 0.02; 
  if (pos > anim.length) {
    clearInterval(0); 
    digitalWrite([LED1,LED2,LED3], 0); // off status 
    inAnim = false;
    return; 
  } 
  analogWrite(LED1, pos); 
  analogWrite(LED2, pos-1);  
  analogWrite(LED3, pos-2);  
  var i = pos|0;
  var f = pos-i;
  if (i>anim.length-2) {
    i=anim.length-2;
    f=1;
  }
  digitalPulse(B12, 1, 2-E.clip(anim[i][0]*(1-f) + anim[i+1][0]*f,0,1));
  digitalPulse(B13, 1, 2-E.clip(anim[i][1]*(1-f) + anim[i+1][1]*f,0,1));
}

setWatch(onPress, B15, { repeat:true, edge:'falling' });