It is only wired speaker and button.

The pin no of wired are written on program.

button = obniz.wired("Button", {signal:6 , gnd:7 });
speaker = obniz.wired("Speaker", {signal:0 , gnd: 1});

On HTML, you can use "css transform". For example , this is the code of rotate image 90 degree.

document.getElementById("roulette").style = "transform:rotate(90deg);";

To start and stop rotate slowly, add a var speed for rotate degree per frame.

let speed = 0;
  let deg = 0;
  function rotate(){
    deg += speed;
      document.getElementById("roulette").style = "transform:rotate("+deg+"deg);";

  }
  setInterval(rotate,10);

Do you want to beep on the roulette no change? With this, you can beep on 440Hz 10ms.

speaker.play(440);
      await obniz.wait(10);
      speaker.stop();

This is how to know on change of roulette no.

if( Math.floor((deg + speed) / (360/7.0)) -  Math.floor(deg / (360/7.0)) >= 1){
      onRouletteChange();
}

 So, this is the code of rotate and beep.

  let speed = 0;
  let deg = 0;
  function rotate(){
    //on change value
    if( Math.floor((deg + speed) / (360/7.0)) -  Math.floor(deg / (360/7.0)) >= 1){
      onRouletteChange();
    }
    deg += speed;
      document.getElementById("roulette").style = "transform:rotate("+deg+"deg);";

  }
  setInterval(rotate,10);

  async function onRouletteChange(){
    if(!speaker){return;}
      speaker.play(440);
      await obniz.wait(10);
      speaker.stop(); 
  }

To know button state, add var buttonStateand set value of current button state.

button.onchange = function(pressed){
    buttonState = pressed;
  };

And also add var phase for current state of roulette.

phase is setted one of this.

const PHASE_WAIT_FOR_START = 0; 
const PHASE_ROTATE = 1;
const PHASE_STOPPING = 2;
const PHASE_STOPPED = 3;

For example, when phase is PHASE_WAIT_FOR_START and you want to next phase.

if(phase == PHASE_WAIT_FOR_START){
    speed = 0;
    if(buttonState){
       phase = PHASE_ROTATE;
    }
}

 To speed up rulette, change var speed .

if(phase == PHASE_ROTATE){
    speed = speed+0.5;
}

To speed down rulette, change var speed .

if(phase == PHASE_STOPPING){    
    speed = speed-0.2;
}

Those are component of roulette. Let's make it!