3. Infrared (IR) Sensor

The infrared sensor is used to detect obstacles by measuring distance using infrared radiation. The distance measured however is limited to 80cm. It has a transmitter and a receiver of radiation. The output signal differs in accordance to the obstacles. It remains high ‘1’ when there are no obstacles and low ‘0’otherwise. There is also a red led on its back that glows purple when it meets an obstacle.

3.1. Connecting the IR Sensor

The wires of the sensor are as follows:

  • Red – 5V
  • Green – GND
  • Yellow – Digital output
In this example:
  1. Red wire is connected to pin#2
  2. Green wire is connected to pin#6
  3. Yellow wire is connected to pin#7

The wiring of the Raspberry Pi to the breadboard, and the sensor is shown the figure below:

../_images/infraredsensor.jpg

3.2. Python Program to Show Obstacle Detection

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import RPi.GPIO as GPIO
import time

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(7,GPIO.IN)

while True:
    print GPIO.input(7)	
    time.sleep(0.5)