Title

Programmable Logic Controller Based Fibre Bragg Grating In-ground Intrusion Detection System

Document Type

Conference Proceeding

Publisher

secau, Edith Cowan University

Editor(s)

David Brooks and Craig Valli

Faculty

Faculty of Computing, Health and Science

School

School of Engineering (SOE) / Centre for Communications Engineering Research

RAS ID

13286

Comments

This article was originally published as: Allwood, G. A., Wild, G. , & Hinckley, S. (2011). Programmable Logic Controller Based Fibre Bragg Grating In-ground Intrusion Detection System. Paper presented at the secau 2011 Security Congress: The 4th Australian Security and Intelligence Conference. Perth, Australia. Original article available here

Abstract

In this paper we present an in-ground intrusion detection system for security applications. Here, an optical fibre pressure switch is directly connected to a standard digital input of a programmable logic controller (PLC). This is achieved using an intensiometric detection system, where a laser diode and Fibre Bragg Grating (FBG) are optically mismatched, resulting in a static dc offset from the transmitted and reflected optical power signals. Pressure applied to the FBG, as the intruder stepped on it, induced a wavelength shift in the FBG. The wavelength shift was then converted into an intensity change as the wavelength of the FBG matched the wavelength of the laser. The change in intensity, measured by the optical detectors, resulted in a significant change in the DC offset, behaving as on optical switch. When connected to the PLC the optical pressure switch was used to drive a digital output, sounding an alarm in addition to displaying the intrusion event on the human machine interface.

Access Rights

Open Access