Circuit Lake

Electronic Project and Circuit Collection

Ultrasonic Security System

06/29/2012 Category: AVR, Microcontroller, Security System

This portable security system is built based on Atmega644 microcontroller. It can detect intruders based on their physical presence. The system uses URM37v3.2 ultrasonic sensor which is connected to MCU through rs232 serial communication. To rotate sensor for wide coverage range, the system is equipped with Parallax servomotor. For user interface, there are LCD and keypad wired to PORTC and PORTA of MCU.

Ultrasonic Security Alarm

How It Works?
The ultrasonic transmitter periodically emits ultrasonic signals into an open area in front of it. A rotating servomotor is used to allow the sensor (transmitter and receiver pair) to cover wide range (roughly 180 degrees). If the signal hits a physical object, it will be reflected back and the receiver part of the sensor will capture it and detect its distance. The security system activates sound alarm for alert and sends the object position to PC via RS232. In the PC side, MATLAB script plots object position on a graph and log the record. To keep user notified of potential privacy violation, the system will send log of the record to email. The ultrasonic security system is designed by Gen Masuda and Xuefan Zhang.

Ultrasonic Alarm
Project Firmware, Schematic and Documentation