Sensors 2011, 11(12), 11856-11870; doi:10.3390/s111211856
Article

Characterization of a Low-Cost Optical Flow Sensor When Using an External Laser as a Direct Illumination Source

Received: 21 November 2011; in revised form: 16 December 2011 / Accepted: 17 December 2011 / Published: 20 December 2011
(This article belongs to the Special Issue Ultra-Small Sensor Systems and Components)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: In this paper, a low cost optical flow sensor is combined with an external laser device to measure surface displacements and mechanical oscillations. The measurement system is based on applying coherent light to a diffuser surface and using an optical flow sensor to analyze the reflected and transferred light to estimate the displacement of the surface or the laser spot. This work is focused on the characterization of this measurement system, which can have the optical flow sensor placed at different angles and distances from the diffuser surface. The results have shown that the displacement of the diffuser surface is badly estimated when the optical mouse sensor is placed in front of the diffuser surface (angular orientation >150°) while the highest sensitivity is obtained when the sensor is located behind the diffuser surface and on the axis of the laser source (angular orientation 0°). In this case, the coefficient of determination of the measured displacement, R2, was very high (>0.99) with a relative error of less than 1.29%. Increasing the distance between the surface and the sensor also increased the sensitivity which increases linearly, R2 = 0.99. Finally, this measurement setup was proposed to measure very low frequency mechanical oscillations applied to the laser device, up to 0.01 Hz in this work. The results have shown that increasing the distance between the surface and the optical flow sensor also increases the sensitivity and the measurement range.
Keywords: optical mouse sensor; external laser source; displacement; oscillatory motion
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MDPI and ACS Style

Font, D.; Tresanchez, M.; Pallejà, T.; Teixidó, M.; Palacín, J. Characterization of a Low-Cost Optical Flow Sensor When Using an External Laser as a Direct Illumination Source. Sensors 2011, 11, 11856-11870.

AMA Style

Font D, Tresanchez M, Pallejà T, Teixidó M, Palacín J. Characterization of a Low-Cost Optical Flow Sensor When Using an External Laser as a Direct Illumination Source. Sensors. 2011; 11(12):11856-11870.

Chicago/Turabian Style

Font, Davinia; Tresanchez, Marcel; Pallejà, Tomàs; Teixidó, Mercè; Palacín, Jordi. 2011. "Characterization of a Low-Cost Optical Flow Sensor When Using an External Laser as a Direct Illumination Source." Sensors 11, no. 12: 11856-11870.

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