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node-ble

Bluetooth Low Energy (BLE) library written with pure Node.js (no bindings) - baked by Bluez via DBus

chrvadala Test Coverage Status npm Downloads Donate

Documentation

Install

npm install node-ble

Examples

Provide permissions

In order to allow a connection with the DBus daemon, you have to set up right permissions.

Create the file /etc/dbus-1/system.d/node-ble.conf with the following content (customize with userid)

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
  "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
  <policy user="%userid%">
   <allow own="org.bluez"/>
    <allow send_destination="org.bluez"/>
    <allow send_interface="org.bluez.GattCharacteristic1"/>
    <allow send_interface="org.bluez.GattDescriptor1"/>
    <allow send_interface="org.freedesktop.DBus.ObjectManager"/>
    <allow send_interface="org.freedesktop.DBus.Properties"/>
  </policy>
</busconfig>

STEP 1: Get Adapter

To start a Bluetooth Low Energy (BLE) connection you need a Bluetooth adapter.

const {createBluetooth} = require('node-ble')
const {bluetooth, destroy} = createBluetooth()
const adapter = await bluetooth.defaultAdapter()

STEP 2: Start discovering

In order to find a Bluetooth Low Energy device out, you have to start a discovery operation.

if (! await adapter.isDiscovering())
  await adapter.startDiscovery()

STEP 3: Get a device, Connect and Get GATT Server

Use an adapter to get a remote Bluetooth device, then connect to it and bind to the GATT (Generic Attribute Profile) server.

const device = await adapter.waitDevice('00:00:00:00:00:00')
await device.connect()
const gattServer = await device.gatt()

STEP 4a: Read and write a characteristic.

const service1 = await gattServer.getPrimaryService('uuid')
const characteristic1 = await service1.getCharacteristic('uuid')
await characteristic1.writeValue(Buffer.from("Hello world"))
const buffer = await characteristic1.readValue()
console.log(buffer)

STEP 4b: Subscribe to a characteristic.

const service2 = await gattServer.getPrimaryService('uuid')
const characteristic2 = await service2.getCharacteristic('uuid')
await characteristic2.startNotifications()
characteristic2.on('valuechanged', buffer => {
  console.log(buffer)
})
await characteristic2.stopNotifications()

STEP 5: Disconnect

When you have done you can disconnect and destroy the session.

await device.disconnect()
destroy()

Compatibility

This library works on many architectures supported by Linux. It leverages on Bluez driver, a component supported by the following platforms and distributions https://www.bluez.org/about

Node-ble has been tested on the following environment:

  • Raspbian GNU/Linux 10 (buster)
  • Ubuntu 18.04.4 LTS
  • Ubuntu 20.04 LTS
  • Ubuntu 21.10

Changelog

  • 0.x - Beta version
  • 1.0 - First official version
  • 1.1 - Migrates to gh-workflows
  • 1.2 - Upgrades deps
  • 1.3 - Adds typescript definitions #10
  • 1.4 - Upgrades deps
  • 1.5 - Adds write options configuration async writeValue (value, optionsOrOffset = {}) #20; Upgrades deps
  • 1.6 - Upgrades deps and removes some dependencies; migrates to npm; improves gh-actions
  • 1.7 - Fixes compatibility issue #30; Adds JSdoc; Deprecates NodeJS 10 and 12; Upgrades deps;

Contributors

References

Similar libraries

Useful commands

Command Description
rm -r /var/lib/bluetooth/* Clean Bluetooth cache
hciconfig -a Adapter info
hcitool dev Adapter info (through Bluez)
d-feet DBus debugging tool
nvram bluetoothHostControllerSwitchBehavior=never Only on Parallels