The Smart Alarm System is an embedded security solution designed to monitor environmental conditions and detect suspicious activity in real time. The system combines multiple hardware and software components in order to improve safety and provide fast user notifications in critical situations.

The project uses motion detection sensors and ambient light monitoring to determine whether an event should be considered dangerous, such as movement detected during nighttime. When suspicious activity is identified, the system activates visual and sound alarms using LEDs and a PWM-controlled buzzer. In addition, the device communicates through Bluetooth, allowing the user to access system logs and monitor alerts directly from a mobile phone using commands such as GETLOG.

The Smart Alarm System is an embedded security solution designed to detect suspicious activity and alert the user in real time. The system monitors both motion and ambient light levels in the environment and decides whether to trigger an alarm based on predefined conditions.

The core of the system is a microcontroller that acquires data from sensors, processes it, and controls the output devices. When motion is detected in a low-light environment (for example, at night), the system considers the event as an intrusion attempt and activates visual and sound alarms.

The system also includes a Bluetooth module that allows the user to communicate with the device from a smartphone. Through simple commands (e.g., GETLOG), the user can retrieve logs and monitor the system status remotely.

The project is designed to be low-cost, reliable and easily extensible, making it suitable for home security, offices or restricted areas.

Key Features

• Motion detection using PIR sensor
• Ambient light monitoring using LDR
• Sound and visual alarm (buzzer + LEDs)
• Bluetooth communication for remote monitoring
• Event logging and retrieval through GETLOG command
• Low power consumption and real-time operation

_Block Diagram_

• ATmega328P microcontroller
• PIR motion sensor
• Light sensor (LDR)
• Buzzer controlled through PWM
• Status LEDs
• Bluetooth module
• Power supply module