Development of An IoT-Based Smart Home Security System Using Laser Beams and LDR Sensors

This study to analyze the design and performance evaluation of an Internet of Things (IoT) based home security prototype combining RFID access authentication with laser light dependent resistor (LDR) intrusion detection. The prototype employed an Arduino Uno, RFID RC522, laser emitter, LDR voltage divider, relay-controlled solenoid door lock, buzzer, and ESP32-CAM for image acquisition and Telegram notifications. Engineering research involved system design, prototype construction, and subsystem and integrated testing. Across 13 alarm test observations, LDR analog-to-digital converter readings ranged from 56 to 1004, a threshold of 850 distinguished the nine interrupted-beam observations from four uninterrupted-beam observations under the tested lighting conditions. RFID card were detected at distances of 1–6 cm but not at 7–9 cm. Registered credentials activated the door lock, whereas unregistered credentials were rejected. In 30 response-time tests, the buzzer responded in 120.87 ± 4.25 ms (mean ± standard deviation); Telegram transmission required 2290 ± 75.20 ms. The results demonstrate the functional integration of local authentication, beam-interruption detection, actuation, image capture, and remote notification. The findings apply to the tested prototype and environmental and network conditions.