A Flutter plugin for interfacing with HackRF One software-defined radios on Android. This library bridges your Flutter app and the native hackrf_android Java library, enabling direct control and transmission via HackRF from Dart.

Ideal for mobile SDR (Software Defined Radio) applications, remote-control transmitters, educational radio tools, and more.

This guide provides a practical, end-user overview of all available functions in the hackrf_flutter plugin and how to use them in your Flutter app.
All functions are asynchronous (Future) for easy integration with modern Flutter code.

You must initialize the device before calling any other function.

Finds the connected HackRF, requests USB permissions, and prepares the device for use.

• Returns: Future<bool> (true if successful, false otherwise)

import 'package:hackrf_flutter/hackrf_flutter.dart';

final _hackrf = HackrfFlutter();

Future<void> connectToDevice() async {
  bool isReady = await _hackrf.init();
  if (isReady) {
    print("HackRF is connected and ready.");
  } else {
    print("Could not find or connect to HackRF.");
  }
}

Retrieves the board ID of the connected HackRF.

• Returns: Future<int?> (board ID, or null if not found)

int? boardId = await _hackrf.getBoardId();
print("Device Board ID: $boardId"); // e.g., 2 for HackRF One

Configure parameters used by both transmitter and receiver.

Sets the center frequency of the HackRF.

• freqHz: Frequency in Hertz (e.g., 145100000 for 145.1 MHz)
• Returns: Future<bool> (true on success)

await _hackrf.setFrequency(145100000);

Sets the sample rate.

• rateHz: Sample rate in Hertz (e.g., 8000000 for 8 MSPS)
• Returns: Future<bool> (true on success)

await _hackrf.setSampleRate(8000000);

Functions for transmitting signals.

Sets the transmit VGA (baseband) gain.

• gain: Integer from 0 to 47
• Returns: Future<bool> (true on success)

await _hackrf.setTxVgaGain(30); // Set gain to 30

Puts the HackRF into transmit mode.
After calling this, you can begin sending data.

• Returns: Future<bool> (true on success)

Takes the HackRF out of transmit mode.

• Returns: Future<bool> (true on success)

Sends a packet of I/Q data to the HackRF's transmit queue.

• data: A Uint8List containing interleaved 8-bit I/Q samples.
• NOTE: The native library expects a specific packet size of 262,144 bytes.

// Create a buffer of the required size
const packetSize = 262144;
final iqData = Uint8List(packetSize);

// ... fill iqData with your signal ...

await _hackrf.startTx();
await _hackrf.sendData(iqData); // Send the packet
await _hackrf.stopTx();

Functions for receiving signals.

Sets the receive LNA (low-noise amplifier / RF) gain.

• gain: Integer from 0 to 40, in steps of 8 (i.e., 0, 8, 16, 24, 32, 40)
• Returns: Future<bool> (true on success)

await _hackrf.setRxLnaGain(32);

Sets the receive VGA (baseband) gain.

• gain: Integer from 0 to 62, in steps of 2
• Returns: Future<bool> (true on success)

await _hackrf.setRxVgaGain(20);

Begins listening for incoming I/Q data from the HackRF.
The hardware starts when you subscribe to the returned stream.

• Returns: Stream<Uint8List> (emits packets of I/Q data)

Stops the receiver.
Usually handled automatically when you cancel the stream subscription, but you can call for safety.

• Returns: Future<bool> (true on success)

StreamSubscription<Uint8List>? rxSubscription;

Future<void> startListening() async {
  // 1. Configure the radio for receiving
  await _hackrf.setFrequency(101100000); // 101.1 MHz FM
  await _hackrf.setSampleRate(2000000);
  await _hackrf.setRxLnaGain(24);
  await _hackrf.setRxVgaGain(20);

  // 2. Get the stream and subscribe to it
  final rxStream = _hackrf.startRx();
  rxSubscription = rxStream.listen(
    (data) {
      print("Received a packet with ${data.length} bytes.");
      // ... process your I/Q data here ...
    },
    onError: (e) {
      print("An error occurred in the RX stream: $e");
    },
    onDone: () {
      print("The RX stream is finished.");
    }
  );
}

void stopListening() {
  // 3. To stop receiving, just cancel the subscription
  rxSubscription?.cancel();
  print("Stopped listening.");
}

Tip: Always check the return value of any function for error handling in your app.

• Flutter (Dart): You call methods such as _hackrf.setFrequency().
• MethodChannel: Dart sends method calls to the native side using Flutter MethodChannel.
• Native Plugin (HackrfFlutterPlugin.kt): Receives calls, delegates to Java code.
• Java Library (Hackrf.java in demantz/hackrf_android): Handles USB communication with HackRF.
• HackRF Device: Executes the requested command.

This plugin is a direct bridge to hackrf_android—all core SDR logic and USB handling is provided by that Java library.