Rohit Sangwan
2fe21962d2
* Add queue per device * Improve API and documentation * Update lib/src/universal_ble.dart * Update lib/src/ble_command_queue.dart --------- Co-authored-by: Foti Dim <fdimanidis@gmail.com> Co-authored-by: Foti Dim <foti@navideck.com>
305 lines
10 KiB
Markdown
305 lines
10 KiB
Markdown
# Universal BLE
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[](https://pub.dev/packages/universal_ble)
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A cross-platform (Android/iOS/macOS/Windows/Linux/Web) Bluetooth Low Energy (BLE) plugin for Flutter.
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[Try it online](https://navideck.github.io/universal_ble/), provided your browser supports [Web Bluetooth](https://caniuse.com/web-bluetooth).
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## Features
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- [Scanning](#scanning)
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- [Connecting](#connecting)
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- [Discovering Services](#discovering-services)
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- [Reading & Writing data](#reading--writing-data)
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- [Pairing](#pairing)
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- [Bluetooth Availability](#bluetooth-availability)
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- [Command Queue](#command-queue)
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- [Timeout](#timeout)
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### API Support Matrix
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| API | Android | iOS | macOS | Windows | Linux (beta) | Web |
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| :------------------- | :-----: | :-: | :---: | :-----: | :----------: | :-: |
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| startScan/stopScan | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
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| connect/disconnect | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
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| getConnectedDevices | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ❌ |
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| discoverServices | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
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| readValue | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
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| writeValue | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
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| setNotifiable | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
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| pair/unPair | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ❌ |
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| onPairingStateChange | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ❌ |
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| enableBluetooth | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ❌ |
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| onAvailabilityChange | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
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| requestMtu | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ❌ |
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## Getting Started
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Add universal_ble in your pubspec.yaml:
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```yaml
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dependencies:
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universal_ble:
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```
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and import it wherever you want to use it:
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```dart
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import 'package:universal_ble/universal_ble.dart';
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```
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### Scanning
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```dart
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// Set a scan result handler
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UniversalBle.onScanResult = (scanResult) {
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// e.g. Use scan result to connect
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}
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// Perform a scan
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UniversalBle.startScan();
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// Or optionally add a scan filter
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UniversalBle.startScan(
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scanFilter: ScanFilter(
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withServices: ["SERVICE_UUID"],
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withManufacturerData: ["MANUFACTURER_DATA"]
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)
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);
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// Stop scanning
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UniversalBle.stopScan();
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```
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Before initiating a scan, ensure that Bluetooth is available:
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```dart
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AvailabilityState state = await UniversalBle.getBluetoothAvailabilityState()
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// Start scan only if Bluetooth is powered on
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if (state == AvailabilityState.poweredOn) {
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UniversalBle.startScan();
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}
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// Or listen to bluetooth availability changes
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UniversalBle.onAvailabilityChange = (state) {
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if (state == AvailabilityState.poweredOn) {
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UniversalBle.startScan();
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}
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};
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```
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See the [Bluetooth Availability](#bluetooth-availability) section for more.
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#### Connected Devices
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Already connected devices, either through previous sessions or connected through system settings, won't show up as scan results.
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You can list those devices using `getConnectedDevices()`. You still need to explicitly connect before using them.
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```dart
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// You can set `withServices` to narrow down the results
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await UniversalBle.getConnectedDevices(withServices: []);
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```
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#### Scan Filter
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You can optionally set filters when scanning.
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##### With Services
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When setting this parameter, the scan results will only include devices that advertize any of the specified services. This is the primary filter. All devices are first filtered by services, then further filtered by other criteria. This parameter is mandatory on [web](#web) if you want to access those services.
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```dart
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List<String> withServices;
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```
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##### With ManufacturerData
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Use the `withManufacturerData` parameter to filter devices by manufacturer data. When you pass a list of `ManufacturerDataFilter` objects to this parameter, the scan results will only include devices that contain any of the specified manufacturer data.
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```dart
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List<ManufacturerDataFilter> withManufacturerData;
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```
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##### With namePrefix
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Use the `withNamePrefix` parameter to filter devices by names (case sensitive). When you pass a list of names, the scan results will only include devices that have this name or start with the provided parameter.
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```dart
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List<String> withNamePrefix;
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```
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### Connecting
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```dart
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// Connect to a device using the `deviceId` of the scanResult received from `UniversalBle.onScanResult`
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String deviceId = scanResult.deviceId;
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UniversalBle.connect(deviceId);
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// Disconnect from a device
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UniversalBle.disconnect(deviceId);
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// Get connection state updates
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UniversalBle.onConnectionChanged = (String deviceId, BleConnectionState state) {
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debugPrint('OnConnectionChanged $deviceId, $state');
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}
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```
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### Discovering Services
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After establishing a connection, you need to discover services. This method will discover all services and their characteristics.
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```dart
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// Discover services of a specific device
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UniversalBle.discoverServices(deviceId);
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```
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### Reading & Writing data
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You need to first [discover services](#discovering-services) before you are able to read and write to characteristics.
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```dart
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// Read data from a characteristic
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UniversalBle.readValue(deviceId, serviceId, characteristicId);
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// Write data to a characteristic
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UniversalBle.writeValue(deviceId, serviceId, characteristicId, value);
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// Subscribe to a characteristic
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UniversalBle.setNotifiable(deviceId, serviceId, characteristicId, BleInputProperty.notification);
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// Get characteristic updates in `onValueChanged`
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UniversalBle.onValueChanged = (String deviceId, String characteristicId, Uint8List value) {
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debugPrint('onValueChanged $deviceId, $characteristicId, ${hex.encode(value)}');
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}
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// Unsubscribe from a characteristic
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UniversalBle.setNotifiable(deviceId, serviceId, characteristicId, BleInputProperty.disabled);
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```
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### Pairing
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```dart
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// Pair
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UniversalBle.pair(deviceId);
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// Get the pairing result
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UniversalBle.onPairingStateChange = (String deviceId, bool isPaired, String? error) {
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// Handle Pairing state change
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}
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// Unpair
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UniversalBle.unPair(deviceId);
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// Check current pairing state
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bool isPaired = UniversalBle.isPaired(deviceId);
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```
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### Bluetooth Availability
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```dart
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// Get current Bluetooth availability state
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AvailabilityState availabilityState = UniversalBle.getBluetoothAvailabilityState(); // e.g. poweredOff or poweredOn,
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// Receive Bluetooth availability changes
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UniversalBle.onAvailabilityChange = (state) {
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// Handle the new Bluetooth availability state
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};
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// Enable Bluetooth programmatically
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UniversalBle.enableBluetooth();
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```
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## Command Queue
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By default, all commands are executed in a global queue (`QueueType.global`), with each command waiting for the previous one to finish.
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If you want to parallelize commands between multiple devices, you can set:
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```dart
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// Create a separate queue for each device.
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UniversalBle.queueType = QueueType.perDevice;
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```
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You can also disable the queue completely and parallelize all commands, even for the same device, by using:
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```dart
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// Disable queue
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UniversalBle.queueType = QueueType.none;
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```
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Keep in mind that some platforms (e.g. Android) may not handle well devices that fail to process consecutive commands without a minimum interval. Therefore, it is not advised to set `queueType` to `none`.
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You can get queue updates by setting:
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```dart
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// Get queue state updates
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UniversalBle.onQueueUpdate = (String id, int remainingItems) {
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debugPrint("Queue: $id Remaining: $remainingItems");
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};
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```
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## Timeout
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By default, all commands have a timeout of 10 seconds.
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```dart
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// Change timeout
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UniversalBle.timeout = const Duration(seconds: 10);
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// Disable timeout
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UniversalBle.timeout = null;
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```
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## Platform-Specific Setup
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### Android
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Add the following permissions to your AndroidManifest.xml file:
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```xml
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<uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation" />
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<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
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<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" android:maxSdkVersion="30" />
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<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" android:maxSdkVersion="30" />
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```
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If you use `BLUETOOTH_SCAN` to determine location, modify your AndroidManifest.xml file to include the following entry:
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```xml
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<uses-permission android:name="android.permission.BLUETOOTH_SCAN" tools:remove="android:usesPermissionFlags" tools:targetApi="s" />
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```
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If your app uses location services, remove `android:maxSdkVersion="30"` from the location permission tags.
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### iOS / macOS
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Add `NSBluetoothPeripheralUsageDescription` and `NSBluetoothAlwaysUsageDescription` to Info.plist of your iOS and macOS app.
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Add the `Bluetooth` capability to the macOS app from Xcode.
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### Windows / Linux
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Your Bluetooth adapter needs to support at least Bluetooth 4.0. If you have more than 1 adapters, the first one returned from the system will be picked.
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When publishing on Windows you need to declare the following [capabilities](https://learn.microsoft.com/en-us/windows/uwp/packaging/app-capability-declarations): `bluetooth, radios`.
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### Web
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On web, the `withServices` parameter in the ScanFilter is used as [optional_services](https://developer.mozilla.org/en-US/docs/Web/API/Bluetooth/requestDevice#optionalservices) as well as a services filter. On web you have to set this parameter to ensure that you can access the specified services after connecting to the device. You can leave it empty for the rest of the platforms if your device does not advertize services.
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```dart
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ScanFilter(
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withServices: kIsWeb ? ["SERVICE_UUID"] : [],
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)
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```
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## Customizing Platform Implementation of UniversalBle
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```dart
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// Create a class that extends UniversalBlePlatform
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class UniversalBleMock extends UniversalBlePlatform {
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// Implement all commands
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}
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UniversalBle.setInstance(UniversalBleMock());
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```
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