ESP32 board: Turn ON and OFF LED using Bluetooth from mobile device

This this video how turn ON or OFF LED using your mobile phone and ESP32
To learn how to control 3 LED see This page
The link to use in the "preferences" of Arduino IDE for ESP32 board https://dl.espressif.com/dl/package_esp32_index.json
Resources for this sketch

Arduion Code


 /*
 * Turn LED ON or OFF from your phone
 * 
 * Using ESP32's Bluetooth and Mobile app
 * turn ON and OFF LED
 * 
 * Updated/Written by Ahmad Shamshiri 
 * On August 25, 2019 in Ajax, Ontario, Canada
 * Watch video instruction for this cod:
 * https://youtu.be/4OOFlS75owA
 * www.Robojax.com 
 * 
 Get this code and other Arduino codes from Robojax.com
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 *  * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.* 
 * This code has been download from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

//This example code is in the Public Domain (or CC0 licensed, at your option.)
//By Evandro Copercini - 2018
//
//This example creates a bridge between Serial and Classical Bluetooth (SPP)
//and also demonstrate that SerialBT have the same functionalities of a normal Serial

#include "BluetoothSerial.h"

#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
#endif

BluetoothSerial SerialBT;
int received;// received value will be stored in this variable
char receivedChar;// received value will be stored as CHAR in this variable

const char turnON ='a';
const char turnOFF ='b';
const int LEDpin = 23;

void setup() {
  Serial.begin(115200);
  SerialBT.begin("ESP32_Robojax"); //Bluetooth device name
  Serial.println("The device started, now you can pair it with bluetooth!");
  Serial.println("To turn ON send: a");//print on serial monitor  
  Serial.println("To turn OFF send: b"); //print on serial monitor 
  pinMode(LEDpin, OUTPUT);
 
}

void loop() {
    receivedChar =(char)SerialBT.read();

  if (Serial.available()) {
    SerialBT.write(Serial.read());
  
  }
  if (SerialBT.available()) {
    
    SerialBT.print("Received:");// write on BT app
    SerialBT.println(receivedChar);// write on BT app      
    Serial.print ("Received:");//print on serial monitor
    Serial.println(receivedChar);//print on serial monitor    
    //SerialBT.println(receivedChar);//print on the app    
    //SerialBT.write(receivedChar); //print on serial monitor
    if(receivedChar == turnON)
    {
     SerialBT.println("LED ON:");// write on BT app
     Serial.println("LED ON:");//write on serial monitor
     digitalWrite(LEDpin, HIGH);// turn the LED ON
       
    }
    if(receivedChar == turnOFF)
    {
     SerialBT.println("LED OFF:");// write on BT app
     Serial.println("LED OFF:");//write on serial monitor
      digitalWrite(LEDpin, LOW);// turn the LED off 
    }    
     
  

  }
  delay(20);
}