Web Bluetooth / Characteristic Properties Sample

Available in Chrome 48+ | View on GitHub | Browse Samples

The Web Bluetooth API lets websites discover and communicate with devices over the Bluetooth 4 wireless standard using the Generic Attribute Profile (GATT). It is currently partially implemented in Android M, Chrome OS, Mac, and Windows 10.

This sample illustrates the use of the Web Bluetooth API to display all properties of a specific characteristic from a nearby Bluetooth Low Energy Device. You may want to try this demo with the BLE Peripheral Simulator App from the Google Play Store and check out the Characteristic Properties (Async Await) sample.

Live Output











  
    
      
    
  

  
    
JavaScript Snippet

  

  
    
function onButtonClick() {
  let serviceUuid = document.querySelector('#service').value;
  if (serviceUuid.startsWith('0x')) {
    serviceUuid = parseInt(serviceUuid);
  }

  let characteristicUuid = document.querySelector('#characteristic').value;
  if (characteristicUuid.startsWith('0x')) {
    characteristicUuid = parseInt(characteristicUuid);
  }

  log('Requesting Bluetooth Device...');
  navigator.bluetooth.requestDevice({filters: [{services: [serviceUuid]}]})
  .then(device => {
    log('Connecting to GATT Server...');
    return device.gatt.connect();
  })
  .then(server => {
    log('Getting Service...');
    return server.getPrimaryService(serviceUuid);
  })
  .then(service => {
    log('Getting Characteristic...');
    return service.getCharacteristic(characteristicUuid);
  })
  .then(characteristic => {
    log('> Characteristic UUID:  ' + characteristic.uuid);
    log('> Broadcast:            ' + characteristic.properties.broadcast);
    log('> Read:                 ' + characteristic.properties.read);
    log('> Write w/o response:   ' +
      characteristic.properties.writeWithoutResponse);
    log('> Write:                ' + characteristic.properties.write);
    log('> Notify:               ' + characteristic.properties.notify);
    log('> Indicate:             ' + characteristic.properties.indicate);
    log('> Signed Write:         ' +
      characteristic.properties.authenticatedSignedWrites);
    log('> Queued Write:         ' + characteristic.properties.reliableWrite);
    log('> Writable Auxiliaries: ' +
      characteristic.properties.writableAuxiliaries);
  })
  .catch(error => {
    log('Argh! ' + error);
  });
}