Vibration sensor with tunable signals using bundled fiber probe

A low cost and simple vibration sensor with tunable signals is proposed and demonstrated based on the principle of extrinsic reflective intensity modulation of displacement measurement for monitoring the heart beat.The front slope of the displacement sensor has a sensitivity of 0.44 mV/µm and linearity of 88% within a measurement range between 0 and 100 µm, while for the back slope, it shows a sensitivity of 0.06 mV/µm and linearity of 97% within a range from 150 µm to 750 µm. By placing the diaphragm of the concave surface loudspeaker within the linear range (in the back slope) from the probe, the vibration frequency of the object can be measured with an error percentage of less than 0.2%. The graphs of three various inputs against outputs frequency in sine, square, and triangle waveform show very high linearity up to 99%. Slope for tunable signals (e.g. sine, square and triangle frequency range) is obtained at 0.98 for all waveforms. Effortlessness, long-haul security, low power utilization, wide frequency ranges, lower noise, toughness, linearity and light weight make it is a promising candidate in contrast to other well-set up strategies for vibration frequency detection.