Use of multi-frequency ultrasonic sensors with PIR sensors to enhance the sensing probability of an embedded surveillance system

In this paper we design and implement an embedded surveillance system by use of multi-frequency ultrasonic sensors with multiple Pyroelectric Infrared sensors (PIR). The ultrasonic sensor module consists of a transmitter and a receiver which are placed in a line; however, ultrasonic sensors with the same frequency are disturbed by crosstalk with each other and have a high miss rate. To overcome these disadvantages of the ultrasonic sensor, we propose the use of improved multi-frequency ultrasonic sensors. In order to reduce the miss rate, both ultrasonic sensors and PIR sensors are managed by the majority voting mechanism (MVM).