Android + ESP32 通过蓝牙发送数据 (BLE)

Question

我正在尝试通过蓝牙 (BLE) 从我的 android 应用程序向 esp32 发送数据，但我找不到正确的方法。我现在所能做的就是扫描并找到 ble 设备。我的 arduino 代码工作正常（它正确接收数据），因为我使用了另一个应用程序，它让我将数据发送到 ble 设备，所以我知道 arduino 代码没问题。

我已经在这里搜索了几天 google 如何实现它，但我仍然坚持下去。这是我现在的代码：

扫描仪：

class BluetoothFragment : Fragment() {
    private lateinit var binding: FragmentBluetoothBinding
    private var list : MutableList<BluetoothDevice> = ArrayList()
    private lateinit var  bluetoothAdapter : BluetoothAdapter

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        Log.d("DeviceListActivity", "onCreate()")
        return inflater.inflate(R.layout.fragment_bluetooth, container, false)
    }

    // TODO: 19/05/2021 implementar listener en el recycler view para crear la conexión con el ble

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        binding = FragmentBluetoothBinding.bind(view)
        if (ContextCompat.checkSelfPermission(
                requireContext(),
                Manifest.permission.ACCESS_COARSE_LOCATION
            ) != PackageManager.PERMISSION_GRANTED
        ) {
            val permissions = arrayOf(
                android.Manifest.permission.ACCESS_COARSE_LOCATION,
            )
            ActivityCompat.requestPermissions(requireActivity(), permissions, 0)
        }

        setRecyclerView(list)
    }

    private val bleScanner = object :ScanCallback() {
        override fun onScanResult(callbackType: Int, result: ScanResult?) {
            super.onScanResult(callbackType, result)
            Log.d("pepe","onScanResult: ${result?.device?.address} - ${result?.device?.name}")
            if(result?.device?.name?.isNotEmpty() == true){
                var bluetoothDevice = result?.device?.name?.let { BluetoothDevice(it) }
                if (bluetoothDevice != null) {
                    list.add(bluetoothDevice)
                    bluetoothAdapter.notifyDataSetChanged()
                }
            }
        }

        override fun onBatchScanResults(results: MutableList<ScanResult>?) {
            super.onBatchScanResults(results)
            Log.d("DeviceListActivity","onBatchScanResults:${results.toString()}")
        }

        override fun onScanFailed(errorCode: Int) {
            super.onScanFailed(errorCode)
            Log.d("DeviceListActivity", "onScanFailed: $errorCode")
        }

    }

    private val bluetoothLeScanner: BluetoothLeScanner
        get() {
            val bluetoothManager = requireActivity().getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
            val bluetoothAdapter = bluetoothManager.adapter
            return bluetoothAdapter.bluetoothLeScanner
        }

    class ListDevicesAdapter(context: Context?, resource: Int) : ArrayAdapter<String>(context!!, resource)


    override fun onStart() {
        Log.d("DeviceListActivity","onStart()")
        super.onStart()
        bluetoothLeScanner.startScan(bleScanner)
    }

    override fun onStop() {
        bluetoothLeScanner.stopScan(bleScanner)
        super.onStop()
    }

    private fun setRecyclerView(allCategories: List<BluetoothDevice>) {
        val layoutManager: RecyclerView.LayoutManager = LinearLayoutManager(context)
        binding.rvBluetooth.layoutManager = layoutManager
        bluetoothAdapter = BluetoothAdapter(allCategories)
        binding.rvBluetooth.adapter = bluetoothAdapter
    }
}

Arduino 代码（我正在用它控制一辆小车，所以这就是为什么我有 5 个不同的值）：

#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>

#define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"

// Motor 1
int motor1Pin1 = 23;
int motor1Pin2 = 22;
int enable1Pin = 21;

// Motor 2
int motor2Pin1 = 18;
int motor2Pin2 = 19;
int enable2Pin = 5;

const int freq = 30000;
const int pwmChannel = 0;
const int resolution = 8;
int dutyCycle = 200;

class MyCallbacks: public BLECharacteristicCallbacks {
    void onWrite(BLECharacteristic *pCharacteristic) {
      std::string value = pCharacteristic->getValue();

      if (value.length() > 0) {
        if (value[0] == '1') {
          dutyCycle = 200;
          Serial.println("Moving Forward");
          digitalWrite(motor1Pin1, LOW);
          digitalWrite(motor1Pin2, HIGH);
          digitalWrite(motor2Pin1, LOW);
          digitalWrite(motor2Pin2, HIGH);
          while (dutyCycle <= 255) {
            ledcWrite(pwmChannel, dutyCycle);
            dutyCycle = dutyCycle + 5;
            delay(500);
          }

        }
        if (value[0] == '4') {
          dutyCycle = 200;
          Serial.println("Moving Backwards");
          digitalWrite(motor1Pin1, HIGH);
          digitalWrite(motor1Pin2, LOW);
          digitalWrite(motor2Pin1, HIGH);
          digitalWrite(motor2Pin2, LOW);
          while (dutyCycle <= 255) {
            ledcWrite(pwmChannel, dutyCycle);
            dutyCycle = dutyCycle + 5;
            delay(500);
          }
        }
        if (value[0] == '2') {
          dutyCycle = 100;
          Serial.println("Motor right");
          digitalWrite(motor1Pin1, LOW);
          digitalWrite(motor1Pin2, HIGH);
          digitalWrite(motor2Pin1, HIGH);
          digitalWrite(motor2Pin2, LOW);
        }
        if (value[0] == '3') {
          dutyCycle = 100;
          Serial.println("Motor left");
          digitalWrite(motor1Pin1, HIGH);
          digitalWrite(motor1Pin2, LOW);
          digitalWrite(motor2Pin1, LOW);
          digitalWrite(motor2Pin2, HIGH);
        }
        if (value[0] == '0') {
          Serial.println("Motor stopped");
          digitalWrite(motor1Pin1, LOW);
          digitalWrite(motor1Pin2, LOW);
          digitalWrite(motor2Pin1, LOW);
          digitalWrite(motor2Pin2, LOW);
        }
      }
    }
};


void setup() {
  Serial.begin(115200);
  BLEDevice::init("Andruino");
  BLEServer *pServer = BLEDevice::createServer();

  BLEService *pService = pServer->createService(SERVICE_UUID);

  BLECharacteristic *pCharacteristic = pService->createCharacteristic(
                                         CHARACTERISTIC_UUID,
                                         BLECharacteristic::PROPERTY_WRITE
                                       );

  pCharacteristic->setCallbacks(new MyCallbacks());
  pService->start();

  BLEAdvertising *pAdvertising = pServer->getAdvertising();
  pAdvertising->start();

  pinMode(motor1Pin1, OUTPUT);
  pinMode(motor1Pin2, OUTPUT);
  pinMode(enable1Pin, OUTPUT);

  pinMode(motor2Pin1, OUTPUT);
  pinMode(motor2Pin2, OUTPUT);
  pinMode(enable2Pin, OUTPUT);

  ledcSetup(pwmChannel, freq, resolution);

  ledcAttachPin(enable1Pin, pwmChannel);
  ledcAttachPin(enable2Pin, pwmChannel);
 
  ledcWrite(pwmChannel, dutyCycle);
}

void loop() {

}

如何通过蓝牙将数据从我的 android 应用程序发送到 esp32？

Answer 1

为了让这个工作，如果我是你，我会做以下事情：-

A 部分：使用现有的 Android 应用程序（例如 nRF Connect - 也许您已经完成了这部分）

从 Play 商店下载并安装 nRF Connect 应用程序。
启动 nRF Connect 应用程序并扫描设备。
如果找到，请连接到您的 ESP32。
浏览 GATT table 并找到控制 ESP32 的特征的 UUID 和句柄。这很重要，因为它将在 B 部分中使用。
找到后，尝试将值 0、1、2、3 和 4 写入此特征，并确保一切正常。

如果上面的部分对您来说是新的，请查看下面的链接。如果您已成功完成上述所有操作，请转到 B 部分：-

B 部分：使用您的 Android 应用程序使其正常工作：-

与 nRF Connect 应用程序类似，您的应用程序需要扫描并连接到 ESP32。您可以找到有关如何执行此操作的示例 here.
连接后，您需要浏览 GATT Table 并找到正确的特性。您可以找到此 .
找到正确的特征及其句柄（这是您在上面的第 4 步中记下的）后，继续为该特征写入值。您可以找到示例 here, and .

如果所有这些都已就绪但仍无法正常工作，请检查以下事项：-

Are you waiting for the GATT write completion callback? Also check this.
Are you using the right Android write operation?
您发送的是整数数据而不是字符串数据吗？该应用需要整数数据才能正常工作。

您可以在以下链接中找到有关上述步骤的示例和说明：-

How to Send Data over a BLE Link
Use BLE to connect to devices in an Android app
The Ultimate Guide to Android BLE Development
Getting Started with Bluetooth Low Energy on Android
How to Use Android BLE to Communicate with Devices

Answer 2

我认为最好的方法是从这篇文章开始 - making-android-ble-work-part。

您的数据未传输到设备的原因有很多：

设备固件（使用 nRF Connect 应用检查）
Android 代码中的逻辑错误（翻阅文章尝试修复它们）

Android + ESP32 通过蓝牙发送数据 (BLE)

Android + ESP32 send data over bluetooth (BLE)

android

bluetooth

arduino

bluetooth-lowenergy

esp32