Speedometer

by murgiaMarco

HTML

<div class="container">
  <div id="tachometer">
    <div class="ii">
      <div><b><span class="num_1">0</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_2">1</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_3">2</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_4">3</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_5">4</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_6">5</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_7">6</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_8">7</span></b></div>
      <div><b></b></div>
      <div><b><span class="num_9">8</span></b></div>
    </div>
    <div id="redline"></div>
    <div id="indicator" class="line"></div>
    <div class="pin">
      <div class="inner"></div>
    </div>
  </div>
</div>

CSS

body {
  background: #dfdfdf;
}

.container {
  margin: 40px auto;
  width: 600px;
}

#tachometer {
  background: #171717;
  margin: 100px auto;
  width: 600px;
  height: 600px;
  box-shadow: inset 0px 0px 9px 3px rgba(0, 0, 0, 1);
  border: 5px solid #171717;
  border-radius: 100%;
  display: block;
  position: relative;
}

.ii {
  position: absolute;
  width: 600px;
  height: 600px;
  z-index: 2;
}

.ii div {
  position: absolute;
  width: 600px;
  height: 600px;
  padding: 4px;
  box-sizing: border-box;
}

.ii div b {
  position: absolute;
  display: block;
  left: 50%;
  width: 5px;
  height: 20px;
  background: #FFF;
  margin: 0 -5px 0;
}

.ii div:nth-child(2n+1) b {
  width: 10px;
  height: 35px;
  margin: 0 -5px 0;
}

.ii div:nth-child(1) {
  transform: rotate(240deg);
}

.ii div:nth-child(2) {
  transform: rotate(255deg);
}

.ii div:nth-child(3) {
  transform: rotate(270deg);
}

.ii div:nth-child(4) {
  transform: rotate(285deg);
}

.ii div:nth-child(5) {
  transform: rotate(300deg);
}

.ii div:nth-child(6) {
  transform: rotate(315deg);
}

.ii div:nth-child(7) {
  transform: rotate(330deg);
}

.ii div:nth-child(8) {
  transform: rotate(345deg);
}

.ii div:nth-child(9) {
  transform: rotate(0deg);
}

.ii div:nth-child(10) {
  transform: rotate(15deg);
}

.ii div:nth-child(11) {
  transform: rotate(30deg);
}

.ii div:nth-child(12) {
  transform: rotate(45deg);
}

.ii div:nth-child(13) {
  transform: rotate(60deg);
}

.ii div:nth-child(14) {
  transform: rotate(75deg);
}

.ii div:nth-child(15) {
  transform: rotate(90deg);
}

.ii div:nth-child(16) {
  transform: rotate(105deg);
}

.ii div:nth-child(17) {
  transform: rotate(120deg);
}

[class^="num_"] {
  color: #FFF;
  display: block;
  position: absolute;
  width: 10px;
  font-size: 40px;
  text-align: center;
  text-transform: uppercase;
  font-family: 'Open Sans', sans-serif;
  text-decoration: none;
}

.num_1 {
  transform: rotate(120deg);
  top: 20px;
}

.num_2 {
  transform: rotate(90deg);
  top:...

JavaScript

var minRange = -120;
var maxRange = 120;
var value = 0;
var minValue = 0;
var maxValue = 8;
var range = maxRange - minRange;


function changeSpeed() {

  var speed = Math.random() * (maxValue - minValue) + minValue;
  var element = document.getElementById("indicator");
  //var speed = document.getElementById("speed").value;
  value = speed;
  var rotationValue = ((value * range) / maxValue) + minRange;


  var cssRotation = (element.style.transform).replace("rotate(","").replace("deg)","");
  console.log(cssRotation)
  var r = cssRotation - rotationValue;
  var i = 1;
  var count = 50;
  var delay = 20;

  function loop() {
    if (i >= count) {
      return;
    }
    i += 1;
    //element.style.transform = "rotate(" + rotationValue + "deg)";
    element.style.transform = "rotate(" +(cssRotation - (r * i / count)) + "deg)";
    //console.log("rotate(" +(cssRotation - (r * i / count)) + "deg)");
    setTimeout(loop, delay);
  }
  loop();

setTimeout(changeSpeed, 1000);

}

changeSpeed();