Web Bluetooth / Device Information Characteristics Sample

Available in Chrome 50+ | 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, Linux, and Mac.

This sample illustrates the use of the Web Bluetooth API to read Device Information Service characteristics from a nearby Bluetooth Device. You may want to check out the Device Information Characteristics (Async Await) sample.

Note: The Serial Number String characteristic is blacklisted and forbidden from being accessed.

Live Output


JavaScript Snippet

function onButtonClick() {
  log('Requesting any Bluetooth Device...');
  navigator.bluetooth.requestDevice({
   // filters: [...] <- Prefer filters to save energy & show relevant devices.
      acceptAllDevices: true,
      optionalServices: ['device_information']})
  .then(device => {
    log('Connecting to GATT Server...');
    return device.gatt.connect();
  })
  .then(server => {
    log('Getting Device Information Service...');
    return server.getPrimaryService('device_information');
  })
  .then(service => {
    log('Getting Device Information Characteristics...');
    return service.getCharacteristics();
  })
  .then(characteristics => {
    let queue = Promise.resolve();
    let decoder = new TextDecoder('utf-8');
    characteristics.forEach(characteristic => {
      switch (characteristic.uuid) {

        case BluetoothUUID.getCharacteristic('manufacturer_name_string'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> Manufacturer Name String: ' + decoder.decode(value));
          });
          break;

        case BluetoothUUID.getCharacteristic('model_number_string'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> Model Number String: ' + decoder.decode(value));
          });
          break;

        case BluetoothUUID.getCharacteristic('hardware_revision_string'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> Hardware Revision String: ' + decoder.decode(value));
          });
          break;

        case BluetoothUUID.getCharacteristic('firmware_revision_string'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> Firmware Revision String: ' + decoder.decode(value));
          });
          break;

        case BluetoothUUID.getCharacteristic('software_revision_string'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> Software Revision String: ' + decoder.decode(value));
          });
          break;

        case BluetoothUUID.getCharacteristic('system_id'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> System ID: ');
            log('  > Manufacturer Identifier: ' +
                padHex(value.getUint8(4)) + padHex(value.getUint8(3)) +
                padHex(value.getUint8(2)) + padHex(value.getUint8(1)) +
                padHex(value.getUint8(0)));
            log('  > Organizationally Unique Identifier: ' +
                padHex(value.getUint8(7)) + padHex(value.getUint8(6)) +
                padHex(value.getUint8(5)));
          });
          break;

        case BluetoothUUID.getCharacteristic('ieee_11073-20601_regulatory_certification_data_list'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> IEEE 11073-20601 Regulatory Certification Data List: ' +
                decoder.decode(value));
          });
          break;

        case BluetoothUUID.getCharacteristic('pnp_id'):
          queue = queue.then(_ => characteristic.readValue()).then(value => {
            log('> PnP ID:');
            log('  > Vendor ID Source: ' +
                (value.getUint8(0) === 1 ? 'Bluetooth' : 'USB'));
            if (value.getUint8(0) === 1) {
              log('  > Vendor ID: ' +
                  (value.getUint8(1) | value.getUint8(2) << 8));
            } else {
              log('  > Vendor ID: ' +
                  getUsbVendorName(value.getUint8(1) | value.getUint8(2) << 8));
            }
            log('  > Product ID: ' +
                (value.getUint8(3) | value.getUint8(4) << 8));
            log('  > Product Version: ' +
                (value.getUint8(5) | value.getUint8(6) << 8));
          });
          break;

        default: log('> Unknown Characteristic: ' + characteristic.uuid);
      }
    });
    return queue;
  })
  .catch(error => {
    log('Argh! ' + error);
  });
}

/* Utils */

function padHex(value) {
  return ('00' + value.toString(16).toUpperCase()).slice(-2);
}

function getUsbVendorName(value) {
  // Check out page source to see what valueToUsbVendorName object is.
  return value +
      (value in valueToUsbVendorName ? ' (' + valueToUsbVendorName[value] + ')' : '');
}