TemplateForEsp32BLE.cpp

#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
#include <BLE2901.h> //this is the name descriptor 

/*Defines*/
#define DEVICE_NAME "GLOVE SENSOR"
bool deviceConnected = false;
bool oldDeviceConnected = false;

#define SERVICE_1_UUID "186ff4e3-45c7-4b73-8db2-6612a3278c2b"
#define CHARACTERISTIC_1A_UUID "ed0fe5c3-1064-47e5-b9d9-f6912652e16d"

/*Callbacks*/
class MyServerCallbacks : public BLEServerCallbacks { // we are writing a class and it is a subclass of BLEServerCallbacks

  void onConnect(BLEServer *pServer) {
    deviceConnected = true; // these are our function signatures 
    digitalWrite(2, HIGH);
    Serial.println("Client Connected");
  }

   void onDisconnect(BLEServer *pServer) { // these are our function signatures
   deviceConnected = false;
    digitalWrite(2, LOW);
    delay(500);
    Serial.println("Client Disconnected");

   }
};



class MyCharacteristicCallbacks: public BLECharacteristicCallbacks{

  void onRead(BLECharacteristic *pCharacteristic){
    uint32_t currentMillis = millis()/1000;
    pCharacteristic -> setValue(currentMillis);
  }
};

void setup() {
  // put your setup code here, to run once:

 
  Serial.begin(9600);
  Serial.println("ESP32 BLE Server setup beginning...");

  //Pin mode 
   pinMode(2,OUTPUT);


  //initilizating device
  BLEDevice::init(DEVICE_NAME); //BLEDevice is a class and they want only one device to be initilized, library uses a lot of static function


  //creating server
  BLEServer *pServer = BLEDevice::createServer(); // holds the address of the server 
  pServer -> setCallbacks(new MyServerCallbacks()); // when we use a pointer we have to use the -> instead of . operator, just creates a new server call back ahandler to the server


  //Services
  BLEService *pService = pServer->createService(SERVICE_1_UUID); //we are making a new pointer called pServer which is pointing to a BLEService Object  which we are using the createServer class to create a service

  //characteristics
  BLECharacteristic *pCharacteristic = pService ->createCharacteristic( // pCharacteristic is pointing to the BLECharacteristic Object and the refrence is being provided by pService & a refrence is just attached to what variable we are using and cannot be detached 
    CHARACTERISTIC_1A_UUID,
    BLECharacteristic::PROPERTY_READ | BLECharacteristic::PROPERTY_WRITE // we need to take the UUID and it wants some properties like a read, write, and notify by changing the bits on different bits

  );

  pCharacteristic->setCallbacks(new MyCharacteristicCallbacks());

 


  //descriptors
  BLE2901 *pDescriptor_2901 = new BLE2901();//creating a new descriptor using 2901
  pDescriptor_2901 ->setDescription("Time"); //having the pointer descriptor have the function of counting time
  pCharacteristic ->addDescriptor(pDescriptor_2901); //since it is nested ble the pCharacteristic is pointed to the pDescriptor using the function of addDescriptor
  
  pService->start();  // starting from the pService class


  //start advertisng 
  BLEAdvertising *pAdvertising = BLEDevice::getAdvertising(); // we have a pointer that is pointing to the class BLEAdvertising and we are getting the BLEDevice to get the getAdvertising object

  // there is passive scan and active scan  the passive scan is basically for the bare minimum information while an active scan is for more information by getting a querey w/o connecting to it 

  BLEAdvertisementData advertismentData;// this is for passive scannning  we are making an instance of the BLEAdvertismentData 
  advertismentData.setName(DEVICE_NAME); // the advertismentData has some functions like setName and manufactureData
  advertismentData.setManufacturerData("Chinese Factory");

  BLEAdvertisementData scanResponseData; //active scanning creating a new object for active sccanning from the BLEAdvertisment data 
  scanResponseData.setName("Extra Scan Data");

  pAdvertising->setAdvertisementData(advertismentData); // this is what data is going to be spat out by the device
  pAdvertising->setScanResponseData(scanResponseData);

  pAdvertising ->addServiceUUID(SERVICE_1_UUID); //we are adding our SERVICE_1_UUID to our pointer for advertising
  pAdvertising ->setScanResponse(true); // when someone qurries/asks for data we will send them data 


  BLEDevice::startAdvertising();


}


void loop(){
  //handle reconnection 
  if(!deviceConnected && oldDeviceConnected){ // if the device isn't connected & the oldDevice isnt connected due to it being false then we start advertising again after a delay 
    delay(500);
    BLEDevice::startAdvertising();
    Serial.println("Restarting...");
    oldDeviceConnected = deviceConnected;
  }
  else if(deviceConnected && !oldDeviceConnected) { //else then the old device is the same as the device that is currently connected
    oldDeviceConnected = deviceConnected;
  }
}