An Optical Sensing based System for Real Time Measurement of Vibration of a Cantilever Beam

We present here in details about the development and experimental validation of an optical sensing-based system for measurement of vibration of a cantilever beam. The system consists of a light dependent resistor, a light emitting diode, a signal conditioning circuit, and a data acquisition system for real-time monitoring. The light dependent resistor detects light intensity variations due to vibration of the beam, which is then converted into voltage signals and processed by using a buffer and an instrumentation amplifier circuit. The amplified signal is measured by using a digital storage oscilloscope and recorded by LabVIEW-based data acquisition system, allowing precise measurement of displacement, frequency, and phase of the vibrating beam. Experiments are conducted on four different cantilever specimens with varying mechanical properties. The vibration parameters obtained from LabVIEW-based analysis are in agreement with parameters measured by using digital storage oscilloscope, establishing the accuracy and reliability of the proposed system. The novelty of the proposed system lies in its simple in design, use of inexpensive components for instrumentation and independency of surface reflectivity of the cantilever beam. The proposed system offers an alternative to traditional vibration measurement techniques, making it suitable for applications in structural health monitoring, material characterization, and industrial diagnostics. Future work will focus on improving ambient light compensation, multi-axis vibration detection, and machine learning-based signal analysis for enhanced accuracy.