cordova-plugin-ble-central
Advanced tools
This plugin enables communication between a phone and Bluetooth Low Energy (BLE) peripherals.
The plugin provides a simple JavaScript API for iOS and Android.
Advertising information is returned when scanning for peripherals. Service, characteristic, and property info is returned when connecting to a peripheral. All access is via service and characteristic UUIDs. The plugin manages handles internally.
Simultaneous connections to multiple peripherals are supported.
See the examples for ideas on how this plugin can be used.
Install with Cordova CLI
$ cd /path/to/your/project
$ cordova plugin add cordova-plugin-ble-central
Note that this plugin's id changed from com.megster.cordova.ble to cordova-plugin-ble-central as part of the migration from the Cordova plugin repo to npm.
Scan and discover BLE peripherals.
ble.scan(services, seconds, success, failure);
Function scan scans for BLE devices. The success callback is called each time a peripheral is discovered. Scanning automatically stops after the specified number of seconds.
{
"name": "TI SensorTag",
"id": "BD922605-1B07-4D55-8D09-B66653E51BBA",
"rssi": -79,
"advertising": /* ArrayBuffer or map */
}
Advertising information format varies depending on your platform. See Advertising Data for more information.
ble.scan([], 5, function(device) {
console.log(JSON.stringify(device));
}, failure);
Scan and discover BLE peripherals.
ble.startScan(services, success, failure);
Function startScan scans for BLE devices. The success callback is called each time a peripheral is discovered. Scanning will continue until stopScan is called.
{
"name": "TI SensorTag",
"id": "BD922605-1B07-4D55-8D09-B66653E51BBA",
"rssi": -79,
"advertising": /* ArrayBuffer or map */
}
Advertising information format varies depending on your platform. See Advertising Data for more information.
ble.startScan([], function(device) {
console.log(JSON.stringify(device));
}, failure);
setTimeout(ble.stopScan,
5000,
function() { console.log("Scan complete"); },
function() { console.log("stopScan failed"); }
);
Stop scanning for BLE peripherals.
ble.stopScan(success, failure);
Function stopScan stops scanning for BLE devices.
ble.startScan([], function(device) {
console.log(JSON.stringify(device));
}, failure);
setTimeout(ble.stopScan,
5000,
function() { console.log("Scan complete"); },
function() { console.log("stopScan failed"); }
);
/* Alternate syntax
setTimeout(function() {
ble.stopScan(
function() { console.log("Scan complete"); },
function() { console.log("stopScan failed"); }
);
}, 5000);
*/
Connect to a peripheral.
ble.connect(device_id, connectSuccess, connectFailure);
Function connect connects to a BLE peripheral. The callback is long running. Success will be called when the connection is successful. Service and characteristic info will be passed to the success callback in the peripheral object. Failure is called if the connection fails, or later if the peripheral disconnects. An peripheral object is passed to the failure callback.
Disconnect.
ble.disconnect(device_id, [success], [failure]);
Function disconnect disconnects the selected device.
Reads the value of a characteristic.
ble.read(device_id, service_uuid, characteristic_uuid, success, failure);
Function read reads the value of the characteristic.
Raw data is passed from native code to the callback as an ArrayBuffer.
Writes data to a characteristic.
ble.write(device_id, service_uuid, characteristic_uuid, value, success, failure);
Function write writes data to a characteristic.
Use an ArrayBuffer when writing data.
// send 1 byte to switch a light on
var data = new Uint8Array(1);
data[0] = 1;
ble.write(device_id, "FF10", "FF11", data.buffer, success, failure);
// send a 3 byte value with RGB color
var data = new Uint8Array(3);
data[0] = 0xFF; // red
data[0] = 0x00; // green
data[0] = 0xFF; // blue
ble.write(device_id, "ccc0", "ccc1", data.buffer, success, failure);
// send a 32 bit integer
var data = new Uint32Array(1);
data[0] = counterInput.value;
ble.write(device_id, SERVICE, CHARACTERISTIC, data.buffer, success, failure);
Writes data to a characteristic without confirmation from the peripheral.
ble.writeWithoutResponse(device_id, service_uuid, characteristic_uuid, value, success, failure);
Function writeWithoutResponse writes data to a characteristic without a response from the peripheral. You are not notified if the write fails in the BLE stack. The success callback is be called when the characteristic is written.
Register to be notified when the value of a characteristic changes.
ble.startNotification(device_id, service_uuid, characteristic_uuid, success, failure);
Function startNotification registers a callback that is called every time the value of a characteristic changes. This method handles both notifications and indications. The success callback is called multiple times.
Raw data is passed from native code to the success callback as an ArrayBuffer.
var onData = function(buffer) {
// Decode the ArrayBuffer into a typed Array based on the data you expect
var data = new Uint8Array(buffer);
alert("Button state changed to " + data[0]);
}
ble.startNotification(device_id, "FFE0", "FFE1", onData, failure);
Stop being notified when the value of a characteristic changes.
ble.stopNotification(device_id, service_uuid, characteristic_uuid, success, failure);
Function stopNotification stops a previously registered notification callback.
Reports the connection status.
ble.isConnected(device_id, success, failure);
Function isConnected calls the success callback when the peripheral is connected and the failure callback when not connected.
ble.isConnected(
'FFCA0B09-CB1D-4DC0-A1EF-31AFD3EDFB53',
function() {
console.log("Peripheral is connected");
},
function() {
console.log("Peripheral is *not* connected");
}
);
Reports if bluetooth is enabled.
ble.isEnabled(success, failure);
Function isEnabled calls the success callback when Bluetooth is enabled and the failure callback when Bluetooth is not enabled.
ble.isEnabled(
function() {
console.log("Bluetooth is enabled");
},
function() {
console.log("Bluetooth is *not* enabled");
}
);
Show the Bluetooth settings on the device.
ble.showBluetoothSettings(success, failure);
Function showBluetoothSettings opens the Bluetooth settings for the operating systems.
showBluetoothSettings is not supported on iOS.
ble.showBluetoothSettings();
Enable Bluetooth on the device.
ble.enable(success, failure);
Function enable prompts the user to enable Bluetooth.
enable is only supported on Android and does not work on iOS.
If enable is called when Bluetooth is already enabled, the user will not prompted and the success callback will be invoked.
ble.enable(
function() {
console.log("Bluetooth is enabled");
},
function() {
console.log("The user did *not* enable Bluetooth");
}
);
Peripheral Data is passed to the success callback when scanning and connecting. Limited data is passed when scanning.
{
"name": "Battery Demo",
"id": "20:FF:D0:FF:D1:C0",
"advertising": [2,1,6,3,3,15,24,8,9,66,97,116,116,101,114,121],
"rssi": -55
}
After connecting, the peripheral object also includes service, characteristic and descriptor information.
{
"name": "Battery Demo",
"id": "20:FF:D0:FF:D1:C0",
"advertising": [2,1,6,3,3,15,24,8,9,66,97,116,116,101,114,121],
"rssi": -55,
"services": [
"1800",
"1801",
"180f"
],
"characteristics": [
{
"service": "1800",
"characteristic": "2a00",
"properties": [
"Read"
]
},
{
"service": "1800",
"characteristic": "2a01",
"properties": [
"Read"
]
},
{
"service": "1801",
"characteristic": "2a05",
"properties": [
"Read"
]
},
{
"service": "180f",
"characteristic": "2a19",
"properties": [
"Read"
],
"descriptors": [
{
"uuid": "2901"
},
{
"uuid": "2904"
}
]
}
]
}
Bluetooth advertising data is returned in when scanning for devices. The format format varies depending on your platform. On Android advertising data will be the raw advertising bytes. iOS does not allow access to raw advertising data, so a dictionary of data is returned.
The advertising information for both Android and iOS appears to be a combination of advertising data and scan response data.
Ideally a common format (map or array) would be returned for both platforms in future versions. If you have ideas, please contact me.
{
"name": "demo",
"id": "00:1A:7D:DA:71:13",
"advertising": ArrayBuffer,
"rssi": -37
}
Convert the advertising info to a Uint8Array for processing. var adData = new Uint8Array(peripheral.advertising)
Note that iOS uses the string value of the constants for the Advertisement Data Retrieval Keys. This will likely change in the future.
{
"name": "demo",
"id": "D8479A4F-7517-BCD3-91B5-3302B2F81802",
"advertising": {
"kCBAdvDataChannel": 37,
"kCBAdvDataServiceData": {
"FED8": {
"byteLength": 7 /* data not shown */
}
},
"kCBAdvDataLocalName": "demo",
"kCBAdvDataServiceUUIDs": ["FED8"],
"kCBAdvDataManufacturerData": {
"byteLength": 7 /* data not shown */
},
"kCBAdvDataTxPowerLevel": 32,
"kCBAdvDataIsConnectable": true
},
"rssi": -53
}
This plugin uses typed Arrays or ArrayBuffers for sending and receiving data.
This means that you need convert your data to ArrayBuffers before sending and from ArrayBuffers when receiving.
// ASCII only
function stringToBytes(string) {
var array = new Uint8Array(string.length);
for (var i = 0, l = string.length; i < l; i++) {
array[i] = string.charCodeAt(i);
}
return array.buffer;
}
// ASCII only
function bytesToString(buffer) {
return String.fromCharCode.apply(null, new Uint8Array(buffer));
}
You can read more about typed arrays in these articles on MDN and HTML5 Rocks.
UUIDs are always strings and not numbers. Some 16-bit UUIDs, such as '2220' look like integers, but they're not. (The integer 2220 is 0x8AC in hex.) This isn't a problem with 128 bit UUIDs since they look like strings 82b9e6e1-593a-456f-be9b-9215160ebcac. All 16-bit UUIDs should also be passed to methods as strings.
Tests require the Cordova Plugin Test Framework
Create a new project
git clone https://github.com/don/cordova-plugin-ble-central
cordova create ble-test com.example.ble.test BLETest
cd ble-test
cordova platform add android
cordova plugin add ../cordova-plugin-ble-central
cordova plugin add ../cordova-plugin-ble-central/tests
cordova plugin add cordova-plugin-test-framework
Change the start page in config.xml
<content src="cdvtests/index.html" />
Run the app on your phone
cordova run android --device
Apache 2.0
Try the code. If you find an problem or missing feature, file an issue or create a pull request.
FAQs
Bluetooth Low Energy (BLE) Central Plugin
The npm package cordova-plugin-ble-central receives a total of 1,730 weekly downloads. As such, cordova-plugin-ble-central popularity was classified as popular.
We found that cordova-plugin-ble-central demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
Research
A malicious npm package disguised as a WhatsApp client is exploiting authentication flows with a remote kill switch to exfiltrate data and destroy files.
Security News
PyPI now supports digital attestations, enhancing security and trust by allowing package maintainers to verify the authenticity of Python packages.
Security News
GitHub removed 27 malicious pull requests attempting to inject harmful code across multiple open source repositories, in another round of low-effort attacks.