The Smart Alarm System is an embedded security solution designed to detect suspicious activity and notify the user in real time. The system monitors motion and ambient light levels using dedicated sensors and activates visual and sound alarms whenever suspicious events are detected, especially during nighttime conditions.

The main purpose of the project is to provide a simple, low-cost and efficient security system that can be used in homes, offices or restricted areas. In addition to local alarms, the device also supports Bluetooth communication, allowing users to monitor alerts and retrieve system logs remotely from a smartphone.

The initial idea behind the project was to develop a practical embedded system capable of detecting and reporting suspicious events in real time, in order to enhance security and improve response time in potentially dangerous situations.

The project can provide significant value in everyday environments where safety and continuous monitoring are essential, offering an accessible and efficient solution for improving security in homes, offices and other restricted areas.

The architecture of the Smart Alarm System is built around the ATmega328P Microcontroller, which coordinates communication between all hardware and software modules and manages the overall operation of the system.

The PIR Motion Sensor is responsible for detecting movement inside the monitored area. Whenever motion is detected, the sensor sends a digital signal to the microcontroller, which analyzes the event together with the ambient light information.

The Light Sensor (LDR) is used to monitor environmental brightness levels. The sensor is connected to the ADC module of the microcontroller and provides analog values that allow the system to determine whether the environment is in daytime or nighttime conditions.

The ATmega328P Microcontroller processes the information received from both sensors and executes the decision-making logic implemented in software. If suspicious activity is detected, such as movement during low-light conditions, the microcontroller activates the alarm subsystem.

The Buzzer Module is used for generating sound alerts and is controlled through PWM signals generated by the microcontroller. At the same time, the LED Indicators provide visual feedback regarding the current state of the system, such as standby mode, alarm activation or Bluetooth connection status.

The Bluetooth Module (HC-05) enables wireless communication between the embedded system and a smartphone. Through UART communication, the user can monitor alerts, retrieve event logs using commands such as GETLOG and interact remotely with the system.

The Push Buttons allow local interaction with the device and are used for functions such as arming, disarming or resetting the alarm system. These inputs are handled directly by the microcontroller using GPIO pins and interrupt-based detection.

The Power Supply Module provides stable voltage to all hardware components and ensures reliable operation of the entire embedded system.

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