PIR Motion Sensor Alarm System

Introduction

PIR sensors detect infrared radiation from warm bodies, making them perfect for motion detection applications.

How PIR Works

The sensor contains two pyroelectric elements. Motion causes differential heating, generating a signal.

Wiring the Circuit

PIR sensors have three pins: VCC, GND, and OUT. The output goes HIGH when motion is detected.

Basic Alarm Code

Read the sensor state and trigger a buzzer when motion is detected. Add a delay to prevent continuous triggering.

Adding Notifications

With a WiFi module like the ESP8266, you can send push notifications or emails when the alarm triggers.

Next Steps

Add multiple zones, entry/exit delays, or integrate with a home automation system.