Passive Infrared Sensor's also popularly known as PIR sensors are infrared sensors that are used for various purposes. We used the Infrared Sensor to detect intrusion.

The PIR sensors work as mentioned in the below screenshot.

When there is a energy difference between two halves of the sensor, an ouput signal is sent indicating movment in front of the sensor. The sensor generally sends signals between 0 - 2047. When there is a movement the sensor sends a signal between 2048 - 4095

We used the below setup to connect the PIR sensor to a Photon particle.

Just for demo purpose we also used an led to show how we can use signals from the photon to blink an led ( which could be a light alarm in the real world). As can be seen below this was the final setup and we used code written in particle to flash lights on the LED based on signals from the PIR sensor.

Then we used Mosquitto MQTT client to publish the messages from the photon particle. Once the signals were published to the Mosquitto message broker we used a simple web client to relay the messages to an HTML GUI. We also implemented a mail client using SMTP that would send emails to configured mail id's based on the frequency of intrusions.

This project is therefore a end to end implementation of an intrusion detection system based using PIR sensors, Particle Photon, LED, Mosquitto and SMTP.