v1

function makeid(length) {
   var result           = '';
   var characters       = 'ABCDEF0123456789';
   var charactersLength = characters.length;
   for ( var i = 0; i < length; i++ ) {result += characters.charAt(Math.floor(Math.random() * charactersLength));}
   return result;
}

function myLoop() {
  setTimeout(function() {
    pad.notifyChangeColor('#' + makeid(6));
    myLoop();
  }, 1600)
}

myLoop();

v2

function a(){setTimeout(function() {pad.notifyChangeColor('#' + Array(6).fill().map(function(){return 'ABCDEF0123456789'.charAt(Math.floor(Math.random()*16))}).join(''));a();},1600)};
a();