Smart Home Security System

The Passive infrared (PIR) sensors have been employed for human detection, tracking, and identification due to their low cost, small size, and operation stability under varying temperatures. The existing systems employ the passive PIR sensor that uses dual elements to form a differential measurement, so that it can detect the thermal change of the environment (rather than the absolute temperature). This configuration enables it to detect the moving thermal source, but also limits its application for static targets. PIR based security system saves the power consumption and memory space of the recording systems has been proposed. PIR (passive infrared radiation) sensors detect the change in infrared radiations of warm blooded moving objects in its detection range. According to the change in infrared radiations there is a change in the voltage generated which is then amplified and triggers the alarm through relay. Pyroelectric sensors are low-cost, low-power small components commonly used only to trigger alarm in presence of humans or moving objects. However, the use of an array of pyroelectric sensors can lead to extraction of more features such as direction of movements, speed, number of people and other characteristics. In this work a low-cost pyroelectric infrared sensor based wireless network is set up to be used for tracking people motion. A novel technique is proposed to distinguish the direction of movement and the number of people passing. The approach has low computational requirements, therefore it is well-suited to limited-resources devices such as wireless nodes. Tests performed gave promising results.