#4 Arduino Mega: Bluetooth Communication to Toggle the LED (using HC-05)

byAkshay Daga (APDaga) -November 22, 2017

0

IoT Tutorial #4 [ Arduino Mega Tutorials #4 ]
Here I will demonstrate the mini project, Turning ON / OFF the LED using wireless Serial Communication using Bluetooth Module HC-05 using Arduino Mega (ATMega 2560).

Problem Statement:
- To Turn ON / OFF the LED using wireless Serial Communication (Tx1 and Rx1).
- Serial communication will be done by USB cable (A to B) for cross-checking the output. (through Tx0 and Rx0)

Recommended Internet of Things (IOT) Courses:

Udemy: Complete Guide to Build IOT Things from Scratch to Market

LinkedIn: IoT Foundations: Fundamentals

edX: Introduction to the Internet of Things (IoT)

edureka: IoT Certification Training on Azure

Coursera: An Introduction to Programming the Internet of Things (IOT) Specialization

Eduonix: Internet Of Things (IOT) Bundle

Requirements:
- Arduino Mega (ATMega 2560)
- USB Cable (A to B)
- Android Phone with "Bluetooth Terminal" App installed in it.
- 1 LED
- 1k Resistor
- Bread Board
- Male to Male wires (minimum 6)

Program Outcome:

Output is shown using LED
If Mobile keypad key "a" / "A" is pressed  -> LED ON
If Mobile keypad key "b" / "B" is pressed  -> LED OFF

> Output message displayed on Arduino Terminal on Desktop 
  using serial communication (Tx0 and Rx0).

NOTE:

Baud Rate is set to 9600

Steps:

1. Install "Bluetooth Terminal" app (By Juan Sebastian Ochoa Zambrano) 
   on Android mobile from Play Store.
2. Make Physical Connections of the BLuetooth Module (HC-05) as given below.
3. On Android mobile, Search for Bluetooth and Connect to HC-05 
   and pair it using password "0000" or "1234".
4. Open "Bluetooth Terminal" App on the Mobile and 
   connect to paired HC-05 module

Physical Connection:

Arduino Mega -> BluetoothModule
Pin18(Tx1)   -> Rx
Pin19(Rx1)   -> Tx
Gnd          -> GND
Vcc          -> VCC(+5V)

Pin13        -> LED+
Gnd          -> LED-

Serial Communication through USB cable(Tx0 and Rx0) to
Arduino Terminal(Desktop)is used just to cross verify.

Downloads:

Download link is given in the Description of the YouTube video shown below.

Demonstration:

Program:

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600); //Tx0 and Rx0  //Set Baud Rate to 9600 for Serial Communication Tx0 and Rx0
  Serial1.begin(9600);  //Tx1 and Rx1  //Connected to Bluetooth Module HC-05 (Bluetooth 2.0)
  //Serial2;  //Tx2 and Rx2
  //Serial3;  //Tx3 and Rx3

  pinMode(13, OUTPUT);  //Set Pin 13 as Output (Connected to LED)

  Serial.println("press \"a\" or \"A\" to switch ON the LED");  //To Desktop
  Serial.println("press \"b\" or \"B\" to switch OFF the LED");
  Serial1.println("press \"a\" or \"A\" to switch ON the LED"); //To mobile
  Serial1.println("press \"b\" or \"B\" to switch OFF the LED");
}

void loop() {
  // put your main code here, to run repeatedly:
  
  if(Serial1.available()>0)
  {
    int buffer_value = Serial1.read();
    if(buffer_value == 'a' || buffer_value == 'A')
    {
      digitalWrite(13, HIGH);    //Turn ON LED
      Serial.println("LED ON");  //Arduino Terminal of Desktop 
      Serial1.println("LED ON"); //Bluetooth Terminal on Mobile
    }
    else if(buffer_value == 'b' || buffer_value == 'B')
    {
      digitalWrite(13, LOW);      //Turn OFF LED
      Serial.println("LED OFF");  //Arduino Terminal on Desktop
      Serial1.println("LED OFF"); //Bluetooth Terminal on Mobile 
    }
  }
}

#4 Arduino Mega: Bluetooth Communication to Toggle the LED (using HC-05)

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