main.cpp

/*
    Based on Neil Kolban example for IDF: https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/tests/BLE%20Tests/SampleWrite.cpp
    Ported to Arduino ESP32 by Evandro Copercini
*/

#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>
#include <Base64.h>

// See the following for generating UUIDs:
// https://www.uuidgenerator.net/

#define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"

#define led 32


class MyCallbacks : public BLECharacteristicCallbacks {
    void onWrite(BLECharacteristic *pCharacteristic) {
      String value = pCharacteristic->getValue();

      if (value.length() > 0) {
        Serial.println("*********");
        Serial.print("New value: ");
        for (int i = 0; i < value.length(); i++) {
          Serial.print(value[i]);
        }
        Serial.println();
        Serial.println("*********");
        
        Serial.println(value);
        if (value == "on") {
          digitalWrite(led, HIGH);
        } else if (value == "off") {
          digitalWrite(led, LOW);
        }else if (value =="req_cert") {
          Serial.println("Sending 'new-string-value' to connected device...");
                pCharacteristic->setValue("new-string-value");
                pCharacteristic->notify();
        }
      }
    }
};


void setup() {
  Serial.begin(115200);
  pinMode(led, OUTPUT);

  Serial.println("1- Download and install an BLE scanner app in your phone");
  Serial.println("2- Scan for BLE devices in the app");
  Serial.println("3- Connect to MyESP32");
  Serial.println("4- Go to CUSTOM CHARACTERISTIC in CUSTOM SERVICE and write something");
  Serial.println("5- See the magic =)");

  BLEDevice::init("MyESP32");
  BLEServer *pServer = BLEDevice::createServer();

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

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

  pCharacteristic->setCallbacks(new MyCallbacks());

  pCharacteristic->setValue("Hello World");
  pService->start();

  BLEAdvertising *pAdvertising = pServer->getAdvertising();
  pAdvertising->start();

  BLEDevice::setMTU(512);
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(2000);
}