blia/bt.html

## bt.html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Bluetooth Web API</title>
</head>
<body>
  <button class="bt">BT</button>
  <script>
  let lamp = null
  const log = console.log.bind(console);
  const [button] = document.getElementsByClassName('bt')

      const toBuff = str => {
        const buf = new ArrayBuffer(str.length)
        const view = new Uint8Array(buf)
        for (var i=0; i < str.length; i++) {
          bufView[i] = str.charCodeAt(i)
        }
        return buf
      }

      function str2ab(str) {
        var buf = new ArrayBuffer(str.length);
        var bufView = new Uint8Array(buf);
        for (var i=0, strLen=str.length; i < strLen; i++) {
          bufView[i] = str.charCodeAt(i);
        }
        return buf;
      }

  const handleNotifications = evt => {
    let v = event.target.value;
    let w = Math.round((v.getUint16(1, true) / 100) / 2)
    log(w.toString());
    log(lamp)
    let command = `255,255,255,${w}`
    for (var j = command.length; j < 18; j++) {
      command += ','
    }
    log(command)
    lamp && lamp.writeValue(str2ab(command))

  }

  button.addEventListener('pointerup', function(event) {
    log('called')
    navigator.bluetooth.requestDevice({ filters: [{ services: ['weight_scale'] }] })
    .then(device => (log(device), device.gatt.connect()))
    .then(server => (log(server), server.getPrimaryService(0x181d)))
    .then(service => (log(service), service.getCharacteristic(0x2a9d) ))
    .then(ch => (log(ch), ch ))
    .then(characteristic => {
      myCharacteristic = characteristic;
      return myCharacteristic.startNotifications().then(_ => {
        log('> Notifications started');
        myCharacteristic.addEventListener('characteristicvaluechanged',
          handleNotifications);
        });
    })
    .catch(error => { log(error); });
  });
  </script>
  <button class="bt2">lamp</button>
  <script>

  const [button2] = document.getElementsByClassName('bt2')


  button2.addEventListener('pointerup', function(event) {
    log('called', 0xFFF0)
    navigator.bluetooth.requestDevice({ filters: [{ services: [0xFFF0] }] })
    .then(device => (log(device), device.gatt.connect())) //
    .then(server => (log(server), server.getPrimaryService(0xFFF0)))
    .then(service => (log(service), service.getCharacteristic(0xFFF1) ))
    .then(ch => (log(ch), ch ))
    .then(characteristic => {
      lamp = characteristic
    })
    .catch(error => { log(error); });
  });
  </script>

</body>
</html>
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<title>Bluetooth Web API</title>
	</head>
	<body>
	<button class="bt">BT</button>
	<script>
	let lamp = null
	const log = console.log.bind(console);
	const [button] = document.getElementsByClassName('bt')

	const toBuff = str => {
	const buf = new ArrayBuffer(str.length)
	const view = new Uint8Array(buf)
	for (var i=0; i < str.length; i++) {
	bufView[i] = str.charCodeAt(i)
	}
	return buf
	}

	function str2ab(str) {
	var buf = new ArrayBuffer(str.length);
	var bufView = new Uint8Array(buf);
	for (var i=0, strLen=str.length; i < strLen; i++) {
	bufView[i] = str.charCodeAt(i);
	}
	return buf;
	}

	const handleNotifications = evt => {
	let v = event.target.value;
	let w = Math.round((v.getUint16(1, true) / 100) / 2)
	log(w.toString());
	log(lamp)
	let command = `255,255,255,${w}`
	for (var j = command.length; j < 18; j++) {
	command += ','
	}
	log(command)
	lamp && lamp.writeValue(str2ab(command))

	}

	button.addEventListener('pointerup', function(event) {
	log('called')
	navigator.bluetooth.requestDevice({ filters: [{ services: ['weight_scale'] }] })
	.then(device => (log(device), device.gatt.connect()))
	.then(server => (log(server), server.getPrimaryService(0x181d)))
	.then(service => (log(service), service.getCharacteristic(0x2a9d) ))
	.then(ch => (log(ch), ch ))
	.then(characteristic => {
	myCharacteristic = characteristic;
	return myCharacteristic.startNotifications().then(_ => {
	log('> Notifications started');
	myCharacteristic.addEventListener('characteristicvaluechanged',
	handleNotifications);
	});
	})
	.catch(error => { log(error); });
	});
	</script>
	<button class="bt2">lamp</button>
	<script>

	const [button2] = document.getElementsByClassName('bt2')


	button2.addEventListener('pointerup', function(event) {
	log('called', 0xFFF0)
	navigator.bluetooth.requestDevice({ filters: [{ services: [0xFFF0] }] })
	.then(device => (log(device), device.gatt.connect())) //
	.then(server => (log(server), server.getPrimaryService(0xFFF0)))
	.then(service => (log(service), service.getCharacteristic(0xFFF1) ))
	.then(ch => (log(ch), ch ))
	.then(characteristic => {
	lamp = characteristic
	})
	.catch(error => { log(error); });
	});
	</script>

	</body>
	</html>