基于ESP32的BLE蓝牙开关

构思：

蓝牙无线插座的硬件设备有：ESP32-WROOM-32、OLED（Organic Light-Emitting Diode）显示模块、继电器、电源转换器、插头部件、插座部件。具体结构如下图所示。 

硬件电路的基本工作流程如下:接通电源，模块220V的AC（Alternating current）电流转换成5V的DC（Direct Current）电流，整流电路将5V转为3.3V，ESP32可以获得稳定的电流并正常工作。用户可以用手机打开蓝牙并启动蓝牙APP，手机与插座配对蓝牙，继电器模块发送开启指令后，控制插座开关OLED屏幕开始运行，显示插座运行时间，并通过蓝牙向手机发送数据APP端。

标题

Arduino代码

#include <BLEDevice.h> #include <BLEServer.h> #include <BLEUtils.h> #include <BLE2902.h>  #include <Wire.h> // 引入驱动OLED0.91所需的库 #include <Adafruit_GFX.h> #include <Adafruit_SSD1306.h>   #define SCREEN_WIDTH 128 // 设置OLED单位：像素 #define SCREEN_HEIGHT 32 // 设置OLED高度，单位：像素  // 虽然教程没有使用自定义重置引脚，但是Adafruit_SSD1306库文件库文件 #define OLED_RESET 4 Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);   BLEServer *pServer = NULL; BLECharacteristic * pTxCharacteristic; bool deviceConnected = false; bool oldDeviceConnected = false;  bool deviceswitch = false;  uint8_t txValue = 0;  uint8_t runtime = 0;  // See the following for generating UUIDs: // https://ww.uuidgenerator.net/

#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"


class MyServerCallbacks: public BLEServerCallbacks { 
        
    void onConnect(BLEServer* pServer) { 
        
      deviceConnected = true;
    };

    void onDisconnect(BLEServer* pServer) { 
        
      deviceConnected = false;
    }
};

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

      if (rxValue.length() > 0) { 
        
        Serial.println("*********");
        Serial.print("Received Value: ");
        for (int i = 0; i < rxValue.length(); i++)
          Serial.print(rxValue[i]);
        if(rxValue[0]=='a')
        { 
        
          digitalWrite(2,HIGH);//open switch
          
          deviceswitch=true;

          runtime = millis() / 1000;
        }

        if(rxValue[0]=='b')
          { 
        
            digitalWrite(2,LOW);//open switch
            deviceswitch=false;
          }
        Serial.println();
        Serial.println("*********");
      }
    }
};


void setup() { 
        
  Serial.begin(115200);

  pinMode(2,OUTPUT);//设置输出2脚
  digitalWrite(2,LOW);//默认低电平

  Wire.begin(/*SDA*/22,/*SCL*/21);
  // 初始化OLED并设置其IIC地址为 0x3C
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);

  // Create the BLE Device
  BLEDevice::init("UART Service");

  // Create the BLE Server
  pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

  // Create the BLE Service
  BLEService *pService = pServer->createService(SERVICE_UUID);

  // Create a BLE Characteristic
  pTxCharacteristic = pService->createCharacteristic(
                    CHARACTERISTIC_UUID_TX,
                    BLECharacteristic::PROPERTY_NOTIFY
                  );
                      
  pTxCharacteristic->addDescriptor(new BLE2902());

  BLECharacteristic * pRxCharacteristic = pService->createCharacteristic(
                       CHARACTERISTIC_UUID_RX,
                      BLECharacteristic::PROPERTY_WRITE
                    );

  pRxCharacteristic->setCallbacks(new MyCallbacks());

  // Start the service
  pService->start();

  // Start advertising
  pServer->getAdvertising()->start();
  Serial.println("Waiting a client connection to notify...");
}

void loop() { 
        

    if (deviceConnected) { 
        
        pTxCharacteristic->setValue(&txValue, 1);
        pTxCharacteristic->notify();
        txValue++;
    delay(10); // bluetooth stack will go into congestion, if too many packets are sent
  }

    // disconnecting
    if (!deviceConnected && oldDeviceConnected) { 
        
        delay(500); // give the bluetooth stack the chance to get things ready
        pServer->startAdvertising(); // restart advertising
        Serial.println("start advertising");
        oldDeviceConnected = deviceConnected;
    }
    // connecting
    if (deviceConnected && !oldDeviceConnected) { 
        
    // do stuff here on connecting
        oldDeviceConnected = deviceConnected;
    }
    if(deviceswitch==true)
     { 
        
      words_display();
      display.display();
      //Serial.println("start advertising");
      
     }
}

void words_display()
{ 
        
  uint8_t runtime0 = (millis() / 1000)-runtime;
  // 清除屏幕
  display.clearDisplay();

  // 设置字体颜色,白色可见
  display.setTextColor(WHITE);

  //设置字体大小
  display.setTextSize(1.5);

  //设置光标位置
  display.setCursor(0, 0);
  display.print("BLE SWITCH");

  display.setCursor(0, 10);
  display.print("Run time: ");
  //打印自开发板重置以来的秒数：
  if(runtime0>3600)
  { 
        
      display.print(runtime0/3600);
      display.print(" h");
    }
  if(runtime0>60)
  { 
        
      display.print(runtime0/60);
      display.print(" min");
    }
  else
{ 
        
      display.print(runtime0);
      display.print(" s");
}

  display.setCursor(0, 20);
  //Serial.println(runtime);
  //ESP.restart(); //ESP.reset();
}

最后说明一下，保存的代码有两个文件夹，如果上述不能使用请下载压缩包， 有论述性文章可供参考。