BLE食用说明——Arduino服务端

BLE服务端头文件

#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

BLE特性包

BLECharacteristic *pCharacteristic;
bool deviceConnected = false;

BLE UUID定义

#define SERVICE_UUID           "6E400001-B5A3-F393-E0A9-E50E24DCCA9E" // UART service UUID
#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"
#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"

Server Callback，服务端连接后的回调

class MyServerCallbacks: public BLEServerCallbacks {
    void onConnect(BLEServer* pServer) {
      deviceConnected = true;
    };
 
    void onDisconnect(BLEServer* pServer) {
      deviceConnected = false;
      // 在有设备接入后Advertising广播会被停止，所以要在设备断开连接时重新开启广播
      // 不然的话只有重启ESP32后才能重新搜索到
      pServer->startAdvertising(); //该行效果同 BLEDevice::startAdvertising();
    }
};

 

Characteristic Callback，特性回调

class MyCallbacks: public BLECharacteristicCallbacks {
    void onWrite(BLECharacteristic *pCharacteristic) {
      String rxValue = pCharacteristic->getValue();
 
      if (rxValue.length() > 0) {
        Serial.print("------>Received Value: ");
 
        for (int i = 0; i < rxValue.length(); i++) {
          Serial.print(rxValue[i]);
        }
        Serial.println();
      }
    }
};

注册回调，并开始广播

void setup() {
  Serial.begin(115200);
  
  // Create the BLE Device
  BLEDevice::init("ESP32 BLE Test"); 

创建BLE服务，并且设置服务回调

  // 创建蓝牙服务
  BLEServer *pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

创建链接服务

  //链接服务
  BLEService *pService = pServer->createService(SERVICE_UUID);

创建特性服务

  pCharacteristic = pService->createCharacteristic(CHARACTERISTIC_UUID_TX, BLECharacteristic::PROPERTY_NOTIFY);
                   
  pCharacteristic->addDescriptor(new BLE2902());
  
  BLECharacteristic *pCharacteristic = pService->createCharacteristic(CHARACTERISTIC_UUID_RX, BLECharacteristic::PROPERTY_WRITE);
  
  pCharacteristic->setCallbacks(new MyCallbacks());

开始蓝牙服务

  // 开始蓝牙链接服务
  pService->start();

开始广播服务

  // 开始广播
  pServer->getAdvertising()->start();
  Serial.println("Waiting a client connection to notify...");

 

void loop() {
  if (deviceConnected) {//设备连接后，每秒钟发送txValue。
    memset(BLEbuf, 0, 32);
    memcpy(BLEbuf, (char*)"Hello BLE APP!", 32); 
    pCharacteristic->setValue(BLEbuf);
    
    pCharacteristic->notify(); // Send the value to the app!
    Serial.print("*** Sent Value: ");
    Serial.print(BLEbuf);
    Serial.println(" ***");
  }
  delay(1000);
}