PIR Sensor, a pyroelectric device…

After working on Sensors with Arduino i have dicided to pass my knowledge via blogs. I will start sharing few project that already done and some are in scope but yet to be materilized in Robotics and AI.

I will be posting regular articles here as I build a data collection system using Arduino, python and Sensors. Visulization on collected data is also in scope.

My projects are mainly based on Home security system therefore now onward call my self “The Agent 360!”

I have created a seperate menu “Robotics” at www.ammozon.co.in for all my robotics blog and projects to avoid confusion on Big Data stuff”.

I am not a company but its all just a hobby to me and i love it. i am only a single person working on maintaning to this site, so be patient if the site has any problem, or there are things that need improving, i’m doing the best i can.

Let me know if you have any suggestions, helpful advice at admin@ammozon.co.in.

Lets start with theoratical infomation about our first sensor i.e. PIR(Passive infrared) based security system.

A PIR Sensor is a pyroelectric device that can sense infrared (IR) radiation changes within its viewing range. These sensors are sensitive to moving objects radiating IR. A PIR sensor creates temporary electric potential whenever a change of IR radiation occurs on the viewing range of the sensor, but the electric potential generated is very small in amplitude and must be amplified significantly. That is because PIR sensors cannot be used alone, instead they become one of the key components of a passive infrared device (PID) with some other circuitry. The basic structure of a PID consists of a Fresnel lens, a PIR sensor, an amplifier circuitry and a comparator plus time delayer circuitry.

PIR Sensor based Security System can switch on a lam or alarm when it detects the heat from an object like a moving person. The name Passive Infrared Sensor is called so becauseit receives the infrared rays passively and do not emit any inrrared rays. The alarm that goes off can be manually reset.

The PIR Sensor based Security System provides application of unauthorised intruder detection in household, commercial & industrial premises……promising relatively lower cost of installation and maintenance compared to other existing safety systems.

The same system can act as an Automatic Energy Saving System by switching on the lights along with the buzzer when human presence is detected…..

The applications of the systems include
• Public doorways in grocery stores
• Hospitals
• Libraries
• Hotels
• Staircases
• Military application…..

The future of ectronics industry guarantees the use of PIR sensors integrated with telecommunication and GPS systems to provide sophisticated safety solutions….


• The system is single ended, unlike light beam/laser barriers, which require aligned transmitters and receivers.
• The system is passive: Intruders can’t detect the presence and location of the detectors (unlike radar systems).
• The detectors consume less power than IR- or radar-based units.
• They are unaffected by light, with the detectors working equally well day or night.
• Precision optics enable detectors to cover narrow areas accurately.
• The detectors complement cameras, allowing fewer cameras to cover the area.
• Small size and unobtrusive design help the detectors blend in with their surroundings.


• Can be fooled by someone moving especially slowly.
• If the sensor was set to the required sensitivity, it would be activated by the cooling of a nearby wall in the evening, or by very small animals.
• Someone walking straight towards a PIR sensor, will not be detected until they are very close by.
• PIR sensors are temperature sensitive – they work optimally at ambient air temperatures of around 15-20 degrees Celsius. If the temperature is over 30 degrees, the field of view narrows and the sensor will be less sensitive. Alternatively, if the temperature is below 15 degrees, the field of view widens and smaller or more distant objects will activate the sensor.

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