Investigation on a macro bending based-fiber extensometer as displacement sensor with light source modulation for power supply efficiency

Abstract

This paper describes a fiber extensometer system that utilizes pulse width modulation in its light source for power efficiency reason. The fiber extensometer was used to monitor displacement by intensity modulation techniques based on macro bending effects. The fiber extensometer consisted of an Arduino microcontroller; to modulate laser sources into optical pulses and to regulate data transmission; a bent fiber for displacement sensor, detector and amplifier, GSM module, antennas and power supply system which was solar cell based. The ON - OFF pulse timer from the programming using the C + language in the Arduino sets the pulse time difference ON - OFF of laser light. The modulated light was then launched to the sensor fiber, received and amplified by detector system. When displacement occurs, the diameter of the fiber bent will change as well as the sensor output. Furthermore, the microcontroller instructed the GSM module to send the output signals contain information about displacement to the user's mobile phone in the form of short message service (SMS). It was obtained that power savings that can be achieved using pulse width modulation techniques on this fiber extensometer system reached 30%, compared to that of fiber extensometers that used continuous laser.