IoT-Based Low-Cost Smart Security System with Motion and Temperature Sensing

This study presents a smart, low-cost alarm system with temperature and motion detection capabilities for real-time monitoring and security applications. The system uses a passive infrared (PIR) sensor and LM35 temperature sensor integrated with an ESP8266 microcontroller to send alerts through the IFTTT app, enabling remote monitoring and immediate notifications while simultaneously triggering an audio buzzer through a relay circuit. Low-cost bipolar junction transistors (BJTs) are used for signal amplification and relay switching. Experimental results validate the realized system’s reliability under real-world conditions, with motion tested at different angles and distances, and high temperatures (mimicking fire hazard) applied near the designed and realized printed circuit board (PCB) of the system. The system provides continuous monitoring results on a developed smart dashboard along with both audible alerts and phone notifications to notify the user effectively in real-time with more than 95% accuracy.