BLE code

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

// Define the BLE Service and Characteristic UUIDs
#define SERVICE_UUID        "12345678-1234-5678-1234-56789abcdef0"
#define CHARACTERISTIC_UUID "12345678-1234-5678-1234-56789abcdef1"

// Create a BLE Server and Characteristic
BLEServer *pServer = nullptr;
BLECharacteristic *pCharacteristic = nullptr;

void setup() {
  Serial.begin(115200);
  BLEDevice::init("ESP32_BLE_Server"); // Initialize BLE with a name

  // Create the BLE Server
  pServer = BLEDevice::createServer();

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

  // Create the BLE Characteristic
  pCharacteristic = pService->createCharacteristic(
                      CHARACTERISTIC_UUID,
                      BLECharacteristic::PROPERTY_READ
                    );

  // Set the initial value of the characteristic
  pCharacteristic->setValue("Hello from ESP32");

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

  // Start advertising
  BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
  pAdvertising->addServiceUUID(SERVICE_UUID);
  pAdvertising->start();

  Serial.println("BLE Server is running, waiting for clients to connect...");
}

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