const characteristicsUUID = {

  led:"19b10011-e8f2-537e-4f6c-d104768a1214",

  button:"19b10012-e8f2-537e-4f6c-d104768a1214"

}

let buttonCharacteristic;

let ledCharacteristic;

let myBLE;

​

let buttonValue = 0;

​

function setup() {

  createCanvas(400, 400);

    // Create a p5ble class

  myBLE = new p5ble();

​

  createCanvas(600, 400);

  background("#FFF");

​

  // Create a 'Connect and Start Notifications' button

  const connectButton = createButton('Connect and Start Notifications')

  connectButton.mousePressed(connectAndStartNotify);

  // Create a 'Toggle' button

  const toggleButton = createButton('Toggle');

  toggleButton.position(15, 15);

  toggleButton.mousePressed(toggleLED);

}

​

function draw() {

   noStroke();

​

  if(buttonValue>0){

    fill(color(255, 255, 0));

  }else{

    fill(color(0, 255, 0));

  }

  rect(15, 40, 120, 120);

}

​

function connectAndStartNotify() {

  // Connect to a device by passing the service UUID

  myBLE.connect(serviceUuid, gotCharacteristics);

}

​

// A function that will be called once got characteristics

function gotCharacteristics(error, characteristics) {

  if (error) console.log('error: ', error);

  console.log(characteristics[1].uuid);

  for(let i = 0; i < characteristics.length;i++){

    if(characteristics[i].uuid == characteristicsUUID.button){

      buttonCharacteristic = characteristics[i];

      myBLE.startNotifications(buttonCharacteristic, handleButton);

    }else if(characteristics[i].uuid == characteristicsUUID.led){

      ledCharacteristic = characteristics[i];

    }else{

      console.log("nothing");

    }

  }

  // Start notifications on the first characteristic by passing the characteristic

  // And a callback function to handle notifications

}

​

// A function that will be called once got characteristics

function handleButton(data) {

  console.log('Button: ', data);

  buttonValue = Number(data);

}

​

// A function that toggles the LED

function toggleLED(){

  myBLE.read(ledCharacteristic, handleLED);

}

​

function handleLED(error, data){

  if (error) console.log('error: ', error);

  console.log('LED: ', data);

  myBLE.write(ledCharacteristic, !data);

}