Year
1989
Abstract
The Stellar Systems' E-Flex II is an intrusion detection system for outdoor perimeter and indoor security. The system is designed to be a primary sensor for medium security applications or a secondary sensor for high security applications. The E-Flex II consists of a main processing unit with a sense module and a sensor cable, which is typically attached to a fence surrounding the perimeter to be protected. The sensor cable is a passive detector cable designed on the principle of the triboelectric effect. This effect is defined as an electrical signal generated within a cable by the mechanical stressing of the cable. The sensor module amplifies and filters this electrical signal and passes it to the main processing unit for further analysis. Testing showed that a typical fence produces frequencies in the sensor cable ranging from few hertz to several kilohertz. The sense module filter stages contain a switched capacitor filter circuit tuned to 300Hz. Testing showed the cable has an active response from DC to 5KHz. Attempts to use the system for other applications or on mediums other than fences highlighted the need for launching an investigative study of some of these applications for the E-Flex II. The system is passive which introduces an opportunity for a wide range of applications. The switched capacitor filtering allows for a wide range of bandpass and center frequency selections. This paper covers a study investigating other applications, selecting the optimum center frequency for each application, and outlining the design changes that can be implemented to achieve the variable center frequency for the switchedcapacitor filter.