Lesson 9 IR Receiver Module

Introduction

An infrared-receiver (as shown below) is a component which receives infrared signals and can independently receive infrared rays and output signals compatible with TTL level. It is similar with a normal plastic-packaged transistor in size and is suitable for all kinds of infrared remote control and infrared transmission.

Required Components

• 1 * Raspberry Pi

• 1 * Breadboard

• 1 * IR receiver module

• 1 * IR Remote Controller

• 1 * 3-Pin anti-reverse cable

Experimental Principle

In this experiment, send signals to IR receiver by pressing buttons on the IR remote controller. The counter will add 1 every time it receives signals; in other words, the increased number indicates IR signals are received.

The schematic diagram of the module is as shown below:

Experimental Procedures

Step 1: Build the circuit.

Raspberry Pi	GPIO Extension Board	IR Receiver Module
GPIO0	GPIO17	SIG
3.3V	3V3	VCC
GND	GND	GND

For C Users:

Step 2: Change directory.

cd /home/pi/SunFounder_SensorKit_for_RPi2/C/09_ir_receiver/

Step 3: Compile.

gcc ir_receiver.c -lwiringPi

Note

If it does not work after running, or there is an error prompt wiringPi.h: No such file or directory, please refer to WiringPi to install it.

Step 4: Run.

sudo ./a.out

Code

#include <wiringPi.h>
#include <stdio.h>

#define    IR    0

int cnt = 0;

void myISR(void)
{
    printf("Received infrared. cnt = %d\n", ++cnt);
}

int main(void)
{
    if(wiringPiSetup() == -1){ //when initialize wiring failed,print messageto screen
        printf("setup wiringPi failed !");
        return 1;
    }

    if(wiringPiISR(IR, INT_EDGE_FALLING, &myISR) == -1){
        printf("setup ISR failed !");
        return 1;
    }

    //pinMode(IR, INPUT);

    while(1);

    return 0;
}

For Python Users:

Step 2: Change directory.

cd /home/pi/SunFounder_SensorKit_for_RPi2/Python/

Step 3: Run.

sudo python3 09_ir_receiver.py

Code

#!/usr/bin/env python3
import RPi.GPIO as GPIO

IrPin  = 11
count = 0

def setup():
    GPIO.setmode(GPIO.BOARD)       # Numbers GPIOs by physical location
    GPIO.setup(IrPin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

def cnt(ev=None):
    global count
    count += 1
    print ('Received infrared. cnt = ', count)

def loop():
    GPIO.add_event_detect(IrPin, GPIO.FALLING, callback=cnt) # wait for falling
    while True:
        pass   # Don't do anything

def destroy():
    GPIO.cleanup()                     # Release resource

if __name__ == '__main__':     # Program start from here
    setup()
    try:
        loop()
    except KeyboardInterrupt:  # When 'Ctrl+C' is pressed, the child program destroy() will be  executed.
        destroy()

Press any key of the remote. Then you can see the LED on the module blinking, and “Received infrared. cnt = xxx” printed on the screen. “xxx” means the time you pressed the key(s).