PIR Motion Sensor using Raspberry Pi | Interfacing Tutorial

Table of Contents

In this project, we will see how to implement a PIR Motion Sensor using Raspberry Pi by learning how to interface a PIR Sensor with Raspberry Pi. In this project, when the PIR Sensor detects any human motion, a buzzer is activated. With this interface, you can implement a simple Motion Detection Alarm as a DIY Project.

Overview

Passive Infrared Sensors, often referred to as PIR Sensors (also IR Motion Sensors and Pyroelectric Sensors), are Motions Detectors that basically detects the changes in Infrared Radiations emitted by a person.

Every living and non-living thing which has a temperature greater than absolute zero will emit infrared radiations. Since the emitted energy is in the form of infrared radiation, whose wavelength is greater than that of our visible light, we humans cannot see those radiations.

But PIR Sensors are built to detect those infrared radiations. Hence, they are employed in a variety of applications like Motion Detectors, Security Systems, Intruder Alert and so forth.

The term “Passive” in the PIR Sensor means that the sensor will not emit any infrared energy but rather detects infrared radiations emitted by other objects. This is in contrast to active sensors, which perform both the actions (emitting and detection).

A Brief Note on the PIR Sensor

The PIR Sensor used in this project consists of a Pyroelectric Infrared Sensor, BISS0001 PIR Motion Detector IC, Fresnel lens and a few other components.

PIR Sensor

For connections, the PIR Sensor has three pins namely VCC, DATA and GND. Also, the PIR Sensor has two potentiometers: one for adjusting the sensitivity of the sensor (or rather the sensing distance of the sensor) and the other for adjusting the time for which the Output stays high upon detecting any human movement.

The Fresnel lens covering the Pyroelectric Sensor play an important role in focusing the infrared energy onto the sensor. With the help of this lens, the PIR Sensor can detect objects in 1200 angle. The range of the sensor is 8 meters i.e. it can detect human movement up to 8 meters.

PIR Sensor Adjustments

As mentioned earlier, there are two potentiometers for manually adjusting the sensitivity and output timing.

With the help of the first potentiometer, you can adjust the Sensitivity i.e. the Sensing Distance of the PIR Sensor. The range can be adjusted from 3 meters up to 8 meters. To increase the sensing distance, turn the POT in clockwise direction and to decrease, turn it in anti-clockwise direction.

PIR Motion Sensor using Raspberry Pi PIR Sensor Pins

Coming to the second potentiometer, you can adjust the duration for which the Output of the PIR Sensor stays HIGH. It can be varied anywhere between 0.3s to 600s. To increase the time, turn the POT in clockwise direction and in anti-clockwise direction to decrease the time.

PIR Motion Sensor using Raspberry Pi

As mentioned in the introduction, the aim of this project is to interface a PIR Sensor with Raspberry Pi and implement a PIR Motion Sensor using Raspberry Pi and Python Programming.

I have already implemented PIR Motion Sensor Module in several other projects like Automatic Room Lights using Arduino and PIR SensorAutomatic Door Opener using Arduino and PIR SensorArduino PIR Sensor Tutorial and GSM Based Home Security Alarm System Using Arduino.

The main advantage of the PIR Motion Sensor using Raspberry Pi over all the above mentioned projects is that Raspberry Pi can be easily connected to the Internet and allows IoT based application of the project.

Circuit Diagram

The following Fritzing based images shows all the connections with respect to the PIR Motion Sensor using Raspberry Pi.

PIR Motion Sensor using Raspberry Pi Circuit Diagram

Components Required

  • Raspberry Pi 3 Model B
  • PIR Sensor
  • 5V Buzzer
  • Connecting Wires
  • Mini Breadboard
  • Power Supply
  • Computer

Circuit Design

Connect the VCC and GND pins of the PIR Motion Sensor to +5V and GND pins of the Raspberry Pi. Connect the DATA Pin of the PIR Sensor to GPIO23 i.e. Physical Pin 16 of the Raspberry Pi.

A 5V Buzzer is connected to GPIO24 i.e. Physical Pin 18 of the Raspberry Pi. The other pin of the buzzer is connected to GND.

NOTE:

  • I have directly connected the Buzzer to Raspberry Pi. But if you are not sure, connect it through an NPN Transistor.
  • From the previous Raspberry Pi Projects, you already know that Raspberry Pi Input pins are 3.3V tolerant i.e. they work on 3.3V Logic.
  • If you are wondering why I connected the output Data pin of the PIR Sensor directly to the Raspberry Pi, then you need to be confused as I have checked the output levels of the PIR Sensor on HIGH state and got a result of around 3.5V.
  • You can also check for the same and then proceed with a level converter circuit (voltage divider) if it is required.

Code

The Programming part of the project is implemented using Python. The following is the Python Script for the PIR Motion Sensor using Raspberry Pi.

 

import RPi.GPIO as GPIO
import time
sensor = 16
buzzer = 18
GPIO.setmode(GPIO.BOARD)
GPIO.setup(sensor,GPIO.IN)
GPIO.setup(buzzer,GPIO.OUT)
GPIO.output(buzzer,False)
print “Initialzing PIR Sensor……”
time.sleep(12)
print “PIR Ready…”
print ” “
try:
while True:
if GPIO.input(sensor):
GPIO.output(buzzer,True)
print “Motion Detected”
while GPIO.input(sensor):
time.sleep(0.2)
else:
GPIO.output(buzzer,False)
except KeyboardInterrupt:
GPIO.cleanup()

 

Working

The working of the PIR Motion Sensor using Raspberry Pi is very simple. If the PIR Sensor detects any human movement, it raises its Data Pin to HIGH.

Raspberry Pi upon detecting a HIGH on the corresponding input pin, will activate the Buzzer.

Applications

The applications of the PIR Motion Sensor using Raspberry Pi project have already been mentioned. Some of them are:

  • Automatic Room Light
  • Motion Detection
  • Intruder Alert
  • Automatic Door Opening
  • Home Security System
Facebook
Twitter
LinkedIn
Pinterest

Similar Articles & Blogs

Explore similar articles on various electronics and electrical topics – 

Synchronous Counter

In the previous Asynchronous binary counter tutorial, we saw that the output of one counter stage is connected directly to the clock input of the

Learn More >>

Frequency Division

In the Sequential Logic tutorials we saw how D-type Flip-Flop´s work and how they can be connected together to form a Data Latch. Another useful

Learn More >>

Asynchronous Counter

An Asynchronous counter can have 2n-1 possible counting states e.g. MOD-16 for a 4-bit counter, (0-15) making it ideal for use in Frequency Division applications. But it

Learn More >>

Binary Weighted DAC

Digital-to-Analogue Converters, or DAC’s as they are more commonly known, are the opposite of the Analogue-to-Digital Converters we looked at in a previous tutorial. DAC’s convert binary

Learn More >>

R-2R DAC

We saw in the previous tutorial about the binary weighted digital-to-analogue converter that the analogue output voltage is the weighted sum of the individual inputs, and that

Learn More >>

Analogue to Digital Converter

Analogue-to-Digital Converters, (ADCs) allow micro-processor controlled circuits, Arduinos, Raspberry Pi, and other such digital logic circuits to communicate with the real world. In the real

Learn More >>