### Project 13 I receive a signal

**1.Introduction**

IR is widely used in remote control. In this lesson, we will use a IR receiver module as a decoder of command from any IR remote controller. Thus, you know how IR can realize control of a robot or how IR is applied in interactive works.

**2.Hardware required**

- EASY plug controller Board x1
- USB cable x1
- EASY plug cable x2
- EASY plug IR Receiver Module x1
- EASY plug 1602 I2C Module x1
- Mini IR remote controller x1 (not included)

Below is a brief introduction of IR Receiver Module so you can gain a better idea of how IR remote control works.

![](media/image-20251126150743485.png)

Infrared receiver is a component with functions of reception, amplification, and demodulation. Its internal IC has already completed demodulation so it directly outputs digital signal. This module is usually used together with IR transmitter module. Below are its specifications:

- Power Supply: 5V
- Interface:Digital
- Modulate Frequency: 38Khz
- Module interface socket:JST PH2.0
- Size: 38*20mm
- Weight: 4g

**3.Connection Diagram**

Now, connect the IR Receiver Module to the D11 port of the controller board, and LCD module to IIC port using the EASY plug cables.

![](media/image-20251126150842136.png)

**4.Sample Code**

Connect the board to your PC using the USB cable; copy below code into Arduino IDE, and click upload to upload it to your board.

```c
#include <IRremote.h>    // place file “IRremote.h” under the directory “libraries” of Arduino
#include <Wire.h>    // place file “Wire.h” under the directory “libraries” of Arduino
#include <LiquidCrystal_I2C.h>   // place file “LiquidCrystal_I2C.h” under the directory “libraries” of Arduino
int RECV_PIN = 11; //define input pin on Arduino
IRrecv irrecv(RECV_PIN);
decode_results results;
LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
  lcd.init();                      // initialize the lcd 
  lcd.init();
  // Print a message to the LCD.
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("remote control:");
  irrecv.enableIRIn(); // Start the receiver
}

void loop() 
{
  if (irrecv.decode(&results)) 
  {
    lcd.setCursor(3,1);
    lcd.print(results.value, HEX);
    delay(500);
    irrecv.resume(); // Receive the next value
  }
  else
  {
    lcd.setCursor(3,1);
    lcd.print("          ");
  }
}
```

**5.Result**

After the above are done, you can see the first line of LCD displays “remote control:”; after you press buttons on the remote controller, in the second line of LCD, you can see it displays a hexadecimal number for 0.5S corresponding to each button; if you hold a button in pressed state, you can see the second line displays “FFFFFFFF”.

![](media/image-20251126151036037.png)