A Node.js BLE (Bluetooth Low Energy) central module.

Want to implement a peripheral? Check out bleno.

Note: macOS / Mac OS X, Linux, FreeBSD and Windows are currently the only supported OSes.

Documentation

• Quick Start Example
• Installation
• API docs
• Advanced usage
• Common problems

Quick Start Example

// Read the battery level of the first found peripheral exposing the Battery Level characteristic

const noble = require('@abandonware/noble');

noble.on('stateChange', async (state) => {
  if (state === 'poweredOn') {
    await noble.startScanningAsync(['180f'], false);
  }
});

noble.on('discover', async (peripheral) => {
  await noble.stopScanningAsync();
  await peripheral.connectAsync();
  const {characteristics} = await peripheral.discoverSomeServicesAndCharacteristicsAsync(['180f'], ['2a19']);
  const batteryLevel = (await characteristics[0].readAsync())[0];

  console.log(`${peripheral.address} (${peripheral.advertisement.localName}): ${batteryLevel}%`);

  await peripheral.disconnectAsync();
  process.exit(0);
});

Installation

• Prerequisites
  • OS X
  • Linux
    • Ubuntu, Debian, Raspbian
    • Fedora and other RPM-based distributions
    • Intel Edison
  • FreeBSD
  • Windows
  • Docker
• Installing and using the package

Prerequisites

OS X

• Install Xcode
• On newer versions of OSX, allow bluetooth access on the terminal app: "System Preferences" —> "Security & Privacy" —> "Bluetooth" -> Add terminal app (see Sandboxed terminal)

Linux

• Kernel version 3.6 or above
• libbluetooth-dev needs to be installed. For instructions for specific distributions, see below.
• To set the necessary privileges to run without sudo, see this section. This is required for all distributions (Raspbian, Ubuntu, Fedora, etc). You will not get any errors if running without sudo, but nothing will happen.

Ubuntu, Debian, Raspbian

See the generic Linux notes above first.

sudo apt-get install bluetooth bluez libbluetooth-dev libudev-dev

Make sure node is on your PATH. If it's not, some options:

• Symlink nodejs to node: sudo ln -s /usr/bin/nodejs /usr/bin/node
• Install Node.js using the NodeSource package

Fedora and other RPM-based distributions

See the generic Linux notes above first.

sudo yum install bluez bluez-libs bluez-libs-devel

Intel Edison

See the generic Linux notes above first.

See Configure Intel Edison for Bluetooth LE (Smart) Development.

FreeBSD

Make sure you have GNU Make:

sudo pkg install gmake

Disable automatic loading of the default Bluetooth stack by putting no-ubt.conf into /usr/local/etc/devd/no-ubt.conf and restarting devd (sudo service devd restart).

Unload ng_ubt kernel module if already loaded:

sudo kldunload ng_ubt

Make sure you have read and write permissions on the /dev/usb/* device that corresponds to your Bluetooth adapter.

Windows

node-gyp requirements for Windows

Install the required tools and configurations using Microsoft's windows-build-tools from an elevated PowerShell or cmd.exe (run as Administrator).

npm install --global --production windows-build-tools

node-bluetooth-hci-socket prerequisites

• Compatible Bluetooth 4.0 USB adapter
• WinUSB driver setup for Bluetooth 4.0 USB adapter, using Zadig tool

See @don's setup guide on Bluetooth LE with Node.js and Noble on Windows

Docker

Make sur your container runs with --network=host options and all specific environment preriquisites are verified.

Installing and using the package

npm install @abandonware/noble

const noble = require('@abandonware/noble');

API docs

All operations have two API variants – one expecting a callback, one returning a Promise (denoted by Async suffix).

Additionally, there are events corresponding to each operation (and a few global events).

For example, in case of the "discover services" operation of Peripheral:

• There's a discoverServices method expecting a callback:

  peripheral.discoverServices((error, services) => {
    // callback - handle error and services
  });

• There's a discoverServicesAsync method returning a Promise:

  try {
    const services = await peripheral.discoverServicesAsync();
    // handle services
  } catch (e) {
    // handle error
  }

• There's a servicesDiscover event emitted after services are discovered:

  peripheral.once('servicesDiscover', (services) => {
    // handle services
  });

API structure:

• Scanning and discovery
  • Event: Adapter state changed
  • Start scanning
  • Event: Scanning started
  • Stop scanning
  • Event: Scanning stopped
  • Event: Peripheral discovered
  • Event: Warning raised
• Reset device
• Peripheral
  • Connect
  • Event: Connected
  • Cancel a pending connection
  • Disconnect
  • Event: Disconnected
  • Update RSSI
  • Event: RSSI updated
  • Discover services
  • Discover all services and characteristics
  • Discover some services and characteristics
  • Event: Services discovered
  • Read handle
  • Event: Handle read
  • Write handle
  • Event: Handle written
• Service
  • Discover included services
  • Event: Included services discovered
  • Discover characteristics
  • Event: Characteristics discovered
• Characteristic
  • Read
  • Event: Data read
  • Write
  • Event: Data written
  • Broadcast
  • Event: Broadcast sent
  • Subscribe
  • Event: Notification received
  • Unsubscribe
  • Discover descriptors
  • Event: Descriptors discovered
• Descriptor
  • Read value
  • Event: Value read
  • Write value
  • Event: Value written

Scanning and discovery

Event: Adapter state changed

noble.on('stateChange', callback(state));

state can be one of:

• unknown
• resetting
• unsupported
• unauthorized
• poweredOff
• poweredOn

Start scanning

noble.startScanning(); // any service UUID, no duplicates


noble.startScanning([], true); // any service UUID, allow duplicates


var serviceUUIDs = ['<service UUID 1>', ...]; // default: [] => all
var allowDuplicates = falseOrTrue; // default: false

noble.startScanning(serviceUUIDs, allowDuplicates[, callback(error)]); // particular UUIDs

NOTE: noble.state must be poweredOn before scanning is started. noble.on('stateChange', callback(state)); can be used to listen for state change events.

Event: Scanning started

noble.on('scanStart', callback);

The event is emitted when:

• Scanning is started
• Another application enables scanning
• Another application changes scanning settings

Stop scanning

noble.stopScanning();

Event: Scanning stopped

noble.on('scanStop', callback);

The event is emitted when:

• Scanning is stopped
• Another application stops scanning

Event: Peripheral discovered

noble.on('discover', callback(peripheral));

• peripheral:

  {
    id: '<id>',
    address: '<BT address'>, // Bluetooth Address of device, or 'unknown' if not known
    addressType: '<BT address type>', // Bluetooth Address type (public, random), or 'unknown' if not known
    connectable: trueOrFalseOrUndefined, // true or false, or undefined if not known
    advertisement: {
      localName: '<name>',
      txPowerLevel: someInteger,
      serviceUuids: ['<service UUID>', ...],
      serviceSolicitationUuid: ['<service solicitation UUID>', ...],
      manufacturerData: someBuffer, // a Buffer
      serviceData: [
          {
              uuid: '<service UUID>',
              data: someBuffer // a Buffer
          },
          // ...
      ]
    },
    rssi: integerValue,
    mtu: integerValue // MTU will be null, until device is connected and hci-socket is used
  };

Note: On macOS, the address will be set to '' if the device has not been connected previously.

Event: Warning raised

noble.on('warning', callback(message));

Reset device

noble.reset()

Peripheral

Connect

peripheral.connect([callback(error)]);

Some of the bluetooth devices doesn't connect seamlessly, may be because of bluetooth device firmware or kernel. Do reset the device with noble.reset() API before connect API.

Event: Connected

peripheral.once('connect', callback);

Cancel a pending connection

peripheral.cancelConnect();
// Will emit a 'connect' event with error

Disconnect

peripheral.disconnect([callback(error)]);

Event: Disconnected

peripheral.once('disconnect', callback);

Update RSSI

peripheral.updateRssi([callback(error, rssi)]);

Event: RSSI updated

peripheral.once('rssiUpdate', callback(rssi));

Discover services

peripheral.discoverServices(); // any service UUID

var serviceUUIDs = ['<service UUID 1>', ...];
peripheral.discoverServices(serviceUUIDs[, callback(error, services)]); // particular UUIDs

Discover all services and characteristics

peripheral.discoverAllServicesAndCharacteristics([callback(error, services, characteristics)]);

Discover some services and characteristics

var serviceUUIDs = ['<service UUID 1>', ...];
var characteristicUUIDs = ['<characteristic UUID 1>', ...];
peripheral.discoverSomeServicesAndCharacteristics(serviceUUIDs, characteristicUUIDs, [callback(error, services, characteristics));

Event: Services discovered

peripheral.once('servicesDiscover', callback(services));

Read handle

peripheral.readHandle(handle, callback(error, data));

Event: Handle read

peripheral.once('handleRead<handle>', callback(data)); // data is a Buffer

<handle> is the handle identifier.

Write handle

peripheral.writeHandle(handle, data, withoutResponse, callback(error));

Event: Handle written

peripheral.once('handleWrite<handle>', callback());

<handle> is the handle identifier.

Service

Discover included services

service.discoverIncludedServices(); // any service UUID

var serviceUUIDs = ['<service UUID 1>', ...];
service.discoverIncludedServices(serviceUUIDs[, callback(error, includedServiceUuids)]); // particular UUIDs

Event: Included services discovered

service.once('includedServicesDiscover', callback(includedServiceUuids));

Discover characteristics

service.discoverCharacteristics() // any characteristic UUID

var characteristicUUIDs = ['<characteristic UUID 1>', ...];
service.discoverCharacteristics(characteristicUUIDs[, callback(error, characteristics)]); // particular UUIDs

Event: Characteristics discovered

service.once('characteristicsDiscover', callback(characteristics));

• characteristics

  {
    uuid: '<uuid>',
    properties: ['...'] // 'broadcast', 'read', 'writeWithoutResponse', 'write', 'notify', 'indicate', 'authenticatedSignedWrites', 'extendedProperties'
  };

Characteristic

Read

characteristic.read([callback(error, data)]);

Event: Data read

characteristic.on('data', callback(data, isNotification));

characteristic.once('read', callback(data, isNotification)); // legacy

Emitted when:

• Characteristic read has completed, result of characteristic.read(...)
• Characteristic value has been updated by peripheral via notification or indication, after having been enabled with characteristic.notify(true[, callback(error)])

Note: isNotification event parameter value MAY be undefined depending on platform. The parameter is deprecated after version 1.8.1, and not supported on macOS High Sierra and later.

Write

characteristic.write(data, withoutResponse[, callback(error)]); // data is a Buffer, withoutResponse is true|false

• withoutResponse:
  • false: send a write request, used with "write" characteristic property
  • true: send a write command, used with "write without response" characteristic property

Event: Data written

characteristic.once('write', withoutResponse, callback());

Emitted when characteristic write has completed, result of characteristic.write(...).

Broadcast

characteristic.broadcast(broadcast[, callback(error)]); // broadcast is true|false

Event: Broadcast sent

characteristic.once('broadcast', callback(state));

Emitted when characteristic broadcast state changes, result of characteristic.broadcast(...).

Subscribe

characteristic.subscribe([callback(error)]);

Subscribe to a characteristic.

Triggers data events when peripheral sends a notification or indication. Use for characteristics with "notify" or "indicate" properties.

Event: Notification received

characteristic.once('notify', callback(state));

Emitted when characteristic notification state changes, result of characteristic.notify(...).

Unsubscribe

characteristic.unsubscribe([callback(error)]);

Unsubscribe from a characteristic.

Use for characteristics with "notify" or "indicate" properties

Discover descriptors

characteristic.discoverDescriptors([callback(error, descriptors)]);

Event: Descriptors discovered

characteristic.once('descriptorsDiscover', callback(descriptors));

• descriptors:

  [
    {
      uuid: '<uuid>'
    },
    // ...
  ]

Descriptor

Read value

descriptor.readValue([callback(error, data)]);

Event: Value read

descriptor.once('valueRead', data); // data is a Buffer

Write value

descriptor.writeValue(data[, callback(error)]); // data is a Buffer

Event: Value written

descriptor.once('valueWrite');

Advanced usage

Override default bindings

By default, noble will select appropriate Bluetooth device bindings based on your platform. You can provide custom bindings using the with-bindings module.

var noble = require('@abandonware/noble/with-bindings')(require('./my-custom-bindings'));

Running without root/sudo (Linux-specific)

Run the following command:

sudo setcap cap_net_raw+eip $(eval readlink -f `which node`)

This grants the node binary cap_net_raw privileges, so it can start/stop BLE advertising.

Note: The above command requires setcap to be installed. It can be installed the following way:

• apt: sudo apt-get install libcap2-bin
• yum: su -c \'yum install libcap2-bin\'

Multiple Adapters (Linux-specific)

hci0 is used by default.

To override, set the NOBLE_HCI_DEVICE_ID environment variable to the interface number.

For example, to specify hci1:

sudo NOBLE_HCI_DEVICE_ID=1 node <your file>.js

If you are using multiple HCI devices in one setup you can run two instances of noble with different binding configurations by initializing them seperatly in code:

const HCIBindings = require('@abandonware/noble/lib/hci-socket/bindings');
const Noble = require('@abandonware/noble/lib/noble');

const params = {
  deviceId: 0,
  userChannel: true
};

const noble = new Noble(new HCIBindings(params));

Reporting all HCI events (Linux-specific)

By default, noble waits for both the advertisement data and scan response data for each Bluetooth address. If your device does not use scan response, the NOBLE_REPORT_ALL_HCI_EVENTS environment variable can be used to bypass it.

sudo NOBLE_REPORT_ALL_HCI_EVENTS=1 node <your file>.js

bleno compatibility (Linux-specific)

By default, noble will respond with an error whenever a GATT request message is received. If your intention is to use bleno in tandem with noble, the NOBLE_MULTI_ROLE environment variable can be used to bypass this behaviour.

Note: this requires a Bluetooth 4.1 adapter.

sudo NOBLE_MULTI_ROLE=1 node <your file>.js

Common problems

Maximum simultaneous connections

This limit is imposed by the Bluetooth adapter hardware as well as its firmware.

| Platform | | | :-------------------------------- | --------------------- | | OS X 10.11 (El Capitan) | 6 | | Linux/Windows - Adapter-dependent | 5 (CSR based adapter) |

Sandboxed terminal

On newer versions of OSX, the terminal app is sandboxed to not allow bluetooth connections by default. If you run a script that tries to access it, you will get an Abort trap: 6 error.

To enable bluetooth, go to "System Preferences" —> "Security & Privacy" —> "Bluetooth" -> Add your terminal into allowed apps.

Adapter-specific known issues

Some BLE adapters cannot connect to a peripheral while they are scanning (examples below). You will get the following messages when trying to connect:

Sena UD-100 (Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)): Error: Command disallowed

Intel Dual Band Wireless-AC 7260 (Intel Corporation Wireless 7260 (rev 73)): Error: Connection Rejected due to Limited Resources (0xd)

You need to stop scanning before trying to connect in order to solve this issue.

Backers

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Sponsors

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Useful links

• Bluetooth Development Portal
  • GATT Specifications
• Bluetooth: ATT and GATT

License

Copyright (C) 2015 Sandeep Mistry [email protected]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.