A low cost portable optical fibre sensor measuring instrument (hardware development) / Azmi Ramli

Fibre optie sensor technology is an outgrowth of today's rapidly growing telecommunications and opto-electronic industries. A low-cost portable méasuring instrument by using optical fibre sensor in conjunction with the personal computer is developed. This méasuring instrument has been designed for the measurement of micrometer displacements and colour variations. The scope of my work is to further develop the hardware such as putting in a variable voltage reference, a signal conditioner for the display panel meter, changing the fibre bifiircation, fabricating a new optical fibre sensor cable, using a blue light emitting diode (LED) instead of red light emitting diode (LED) and frnally putting the whole components into a metal box casing. This is done to enhance the reliability and efficiency of the méasuring instrument. The méasuring instrument employed LED as a light source and semiconductor photodiode as a photodetector where it converts the light signals to an electrical signal. The optical fibre cable is used as a media of transmission between light source, sensors and photodetector. All components connection are developed on a breadboard before PCB fabrication. The signal output is in the form of voltage level representing the colour variations or micrometer displacements detected through the same optical fibre sensor. The instrument can measure displacement with an accuracy of ± 5.0 u,m.