PIR Motion Detecting Sensor

3 min readSep 20, 2020

Using this sensor we can detect if there any motion and can be used for security purpose.

A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena. The output is generally a signal that is converted to human-readable display at the sensor location or transmitted electronically over a network for reading or further processing.

Different Types of Sensors

The following is a list of different types of sensors that are commonly used in various applications. All these sensors are used for measuring one of the physical properties like Temperature, Resistance, Capacitance, Conduction, Heat Transfer etc.

Temperature Sensor
Proximity Sensor
Accelerometer
IR Sensor (Infrared Sensor)
Pressure Sensor
Light Sensor
Ultrasonic Sensor
Smoke, Gas and Alcohol Sensor
Touch Sensor
Color Sensor
Humidity Sensor
Tilt Sensor
Flow and Level Sensor

A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared(IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms and automatic lighting applications.

PIR sensors detect general movement, but do not give information on who or what moved. For that purpose, an imaging IR sensor is required.

PIR sensors are commonly called simply “PIR”, or sometimes “PID”, for “passive infrared detector”. The term passive refers to the fact that PIR devices do not radiate energy for detection purposes. They work entirely by detecting infrared radiation(radiant heat) emitted by or reflected from objects.

Generally, PIR can detect animal/human movement in a requirement range, which is determined by the spec of the specific sensor. The detector itself does not emit any energy but passively receives it, detects infrared radiation from the environment. Once there is infrared radiation from the human body/ particle with temperature, focusing on the optical system causes the pyroelectric device to generate a sudden electrical signal and an alarm is issued.