How to Use IR Remote Control with Arduino?

1.Introduction
 

Infrared remote control is a low-cost, easy-to-use wireless communication technology. IR light is very similar to visible light, except that it has a slightly longer wavelength. This means that infrared rays cannot be detected by the human eye, which is perfect for wireless communication. For example, when you press a button on the TV remote control, an infrared LED will switch on and off repeatedly at a frequency of 38,000 times per second, sending information (such as volume or channel control) to the infrared sensor on the TV.
 

We will first explain how common IR communication protocols work. Then we will start this project with a remote control and an IR receiving component. We have prepared a home cartoon board. When we press the button of the remote control, the light on the house will be on, and when we press the button again, it will be off.
 

2.Components Required
 

3.Component Knowledge

What is infrared?

Infrared radiation is a form of light similar to the light we see all around us. The only difference between IR light and visible light is the frequency and wavelength. Infrared radiation lies outside the range of visible light, so humans can’t see it.

Because IR is a type of light, IR communication requires a direct line of sight from the receiver to the transmitter. It can’t transmit through walls or other materials like WiFi or Bluetooth.
 

How IR and receiver work
 

A typical infrared communication system requires an IR transmitter and an IR receiver. The transmitter looks just like a standard LED, except it produces light in the IR spectrum instead of the visible spectrum. If you have a look at TV remote, you’ll see the IR transmitter.

LED:

The IR receiver is a photodiode and pre-amplifier that converts the IR light into an electrical signal. IR receiver diodes typically look like this:

IR signal modulation：
 

IR light is emitted by the sun, light bulbs, and anything else that produces heat. That means there is a lot of IR light noise all around us. To prevent this noise from interfering with the IR signal, a signal modulation technique is used. In IR signal modulation, an encoder on the IR remote controller converts a binary signal into a modulated electrical signal. This electrical signal is sent to the transmitting LED. The transmitting LED converts the modulated electrical signal into a modulated IR light signal. The IR receiver then demodulates the IR light signal and converts it back to binary before passing on the information to a microcontroller.

The modulated IR signal is a series of IR light pulses switched on and off at a high frequency known as the carrier frequency. The carrier frequency used by most transmitters is 38 kHz, because it is rare in nature and thus can be distinguished from ambient noise. This way the IR receiver will know that the 38 kHz signal was sent from the transmitter and not picked up from the surrounding environment. The receiver diode detects all frequencies of IR light, but it has a band-pass filter and only lets through IR at 38 kHz. It then amplifies the modulated signal with a pre-amplifier and converts it to a binary signal before sending it to a microcontroller.

IR Codes:
 

This is the information that is modulated and sent over IR to the receiver. In order to decipher which key is pressed, the receiving microcontroller needs to know which code corresponds to each key on the remote.

Different remotes send different codes for the buttons, so you’ll need to determine the code generated for each key on your particular remote. If you can find the datasheet, the IR key codes should be listed. If not though, there is a simple Arduino sketch that will read most of the popular remote controls and print the hexadecimal codes to the serial monitor when you press a key. I’ll show you how to set up in a minute, but first we need to connect the receiver to the Plus mainboard.
 

4.Decode the IR Signals
 

We connect the infrared receiver module to the Plus mainboard according to the wiring diagram below.

Install the IR remote library:
 

We’ll use the IR remote library for all of the code examples below.

Note: The library file needs to be installed in the code. If the “Arduino-IRremote-master” library file has been added, ignore the process of adding the library file below.

Decompress the library files in the folder, that is, put the decompressed “Arduino-IRremote-master” folder into “Arduino libraries” under the compiler installation directory.After successful placement, you need to restart the compiler, otherwise the compilation will not work.

e.g：C: \Program Files\Arduino\libraries

/*
Decoded_infrared_signal
http//www.keyestudio.com
*/
#include <IRremote.h>
int RECV_PIN = 11;
IRrecv irrecv(RECV_PIN);
decode_results results;
void setup()
{
  Serial.begin(9600);
  irrecv.enableIRIn(); // start receiving signals
}
void loop() {
  if (irrecv.decode(&results)) {
    Serial.println(results.value, HEX);
    irrecv.resume(); // receive the next value
  }
  delay(100);
}

Upload the code to the Plus Mainboard, connect the wires and power on first. Then open the serial monitor at a baud rate of 9600.

You will see a code on the serial monitor. Press the same button several times to make sure you have the right code for that button. If you see FFFFFFFF, just ignore it.

Write down the code associated with each button, because you’ll need that information later.

5. Circuit Diagram and Wiring Diagram
 

Now I’ll show you how to control the Arduino’s output pins using IR remote. In this project, we will light up an LED. You can easily modify the code to do things like control servo motors, or activate relays with any button press from the remote.

Connect the LEDs with resistors to pin 8, 9, 10.

6. Code
 

/*
IR Remote Control
http//www.keyestudio.com
*/
#include <IRremote.h>
int IR_Recv = 11;   //the pin of the IR receiver is 11
int bluePin = 10;
int greenPin = 9;
int yellowPin = 8;
IRrecv irrecv(IR_Recv);
decode_results results;
void setup(){
  Serial.begin(9600);  //start serial communication
  irrecv.enableIRIn(); // start receiving
  pinMode(bluePin, OUTPUT);      // set the digital pin to OUTPUT
  pinMode(greenPin, OUTPUT);      // set the digital pin to OUTPUT
  pinMode(yellowPin, OUTPUT);      // set the digital pin to OUTPUT
}
 void loop(){
  // decode the IR signals input
  if (irrecv.decode(&results)){
    long int decCode = results.value;
    Serial.println(results.value,HEX);
    //switch to case to use the selected remote control button
    switch (results.value){
      case  0x00FF6897: //when you press the button 1
        digitalWrite(bluePin, HIGH);
        break;   
      case  0x00FF30CF: //when you press the button 4
        digitalWrite(bluePin, LOW);   
        break;
       case 0x00FF9867: //when you press the button 2
        digitalWrite(greenPin, HIGH);
        break;           
       case 0x00FF18E7: //when you press the button 5
        digitalWrite(greenPin, LOW);
        break;       
       case 0x00FFB04F: //when you press the button 3
        digitalWrite(yellowPin, HIGH);
        break;       
       case 0x00FF7A85: //when you press the button 6
        digitalWrite(yellowPin, LOW);
        break;
    }
    irrecv.resume(); // receive the next value
  }
  delay(10);
}

Note: Add “IRremote” folder into installation directory Arduino compiler libraries, or you will fail to compile it.

7.Result
 

Upload the code to the Plus mainboard, connect the wires and power on first. Press button 1 and 4 to turn on and off the first LED. Press button 2 and 5 to control the second LED. And press button 3 and 6 to control the state of the third LED.