低功耗蓝牙数据传输源码

以下是一个简单的低功耗蓝牙数据传输的示例代码：

#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"

BLECharacteristic *pCharacteristic;

class MyServerCallbacks: public BLEServerCallbacks {
    void onConnect(BLEServer* pServer) {
      Serial.println("Device connected");
    };

    void onDisconnect(BLEServer* pServer) {
      Serial.println("Device disconnected");
    }
};

void setup() {
  Serial.begin(115200);
  Serial.println("Starting BLE work!");

  BLEDevice::init("MyDevice");
  BLEServer *pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

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

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

  pCharacteristic->setValue("Hello World");

  pService->start();

  BLEAdvertising *pAdvertising = pServer->getAdvertising();
  pAdvertising->addServiceUUID(SERVICE_UUID);
  pAdvertising->setScanResponse(true);
  pAdvertising->setMinPreferred(0x06);  // functions that help with iPhone connections issue
  pAdvertising->setMinPreferred(0x12);
  BLEDevice::startAdvertising();
  Serial.println("Characteristic defined! Now you can read it in your phone!");
}

void loop() {
  // nothing to do here
}

此代码使用了 `BLEDevice` 库，该库提供了便利的封装，使得使用低功耗蓝牙变得更加简单。代码中创建了一个服务和一个特征，特征可读可写。设备初始化后，它将等待连接并将“Hello World”作为特征值返回给连接的设备。