Determining the efficiency of optical sources using a smartphone’s ambient light sensor

Abstract

This work reports the use of a smartphone's ambient light sensor as a valuable tool to study and characterize the efficiency of an optical source. Here, we have measured both luminous efficacy and efficiency of several optical sources (incandescent bulb and halogen lamp) as a function of the electric power consumed and the distance to the optical detector. The illuminance of LEDs as a function of the distance to the optical detector is characterized for different wavelength emissions. Analysis of the results confirms an inverse-square law of the illuminance with the detector-source distance and shows good agreement with values obtained by classical experiments. This experience will trigger awareness in students in terms of sustainability, light propagation and efficiency of different optical sources.

Characterization of linear light sources with the smartphone’s ambient light sensor

“…To perform a new measurement, the sensor was covered with an opaque black cloth until it was placed at the new posi- T he smartphone's ambient light sensor has been used in the literature to study different physical phenomena. [1][2][3][4][5] For instance, Malus's law, which involves the polarized light, has been verified by using simultaneously the orientation and light sensors of a smartphone. 1 The illuminance of point light sources has been characterized also using the light sensor of smartphones and tablets, demonstrating in this way the well-known inverse-square law of distance.…”

“…2,3 Moreover, these kinds of illuminance measurements with the ambient light sensor have allowed the determination of the luminous efficiency of different quasi-point optical sources (incandescent and halogen lamps) as a function of the electric power supplied. 4 Regarding mechanical systems, the inverse-square law of distance has also been used to investigate the speed and acceleration of a moving light source on an inclined plane 5 or to study coupled and damped oscillations. 6 In the present work, we go further in presenting a simple laboratory experiment using the smartphone's ambient light sensor in order to characterize a non-point light source, a linear fluorescent tube in our case.…”

Measurement of spring constants of various spring-mass systems by using smartphones: a teaching proposal

“…It is understandable that when the phone manufacturers have placed the sensors, some of which are light sensors, proximity sensors, accelerometers, gyroscopes, barometers, and magnetometers, they have most likely not anticipated the educational and scientific purposes. Nevertheless, these portable tool boxes lead to a new route to measure many concepts in physics education (Díaz-Melián et al, 2018), to give some examples, in astronomy (Barrera-Garrido, 2015), thermodynamics (Monteiro & Martí, 2016), magnetism (Taspika et al, 2018) and optics (Sans et al, 2016).…”

Smartphones y caída libre: Diseño y evaluación de una experiencia práctica

“…En la bibliografía reciente se pueden encontrar numerosas propuestas de experiencias prácticas de Física basadas en la utilización de smartphones y/o tablets como herramientas de medida en experiencias de mecánica (Kuhn y Vogt, 2012;Vogt y Kuhn, 2012a, 2012bCastro-Palacio, Velázquez-Abad, Giménez y Monsoriu, 2013;Vieyra y Vieyra, 2014;Hochberg, Gröber, Kuhn y Müller, 2014;Monteiro, Stari, Cabeza y Martí, 2015), acústica (Parolin y Pezzi, 2013;Kuhn y Vogt, 2013b;Kuhn, Vogt y Hirth, 2014;Parolin y Pezzi, 2015;González y González, 2016;Di Laccio Caceres et al, 2017) u óptica (Sitar, 2012;Thoms, Colicchia y Girwidz, 2013;Monteiro, Stari, Cabeza y Martí, 2017;Sans et al, 2017;Salinas, Giménez, Monsoriu y Castro-Palacio, 2018). Sin embargo, hasta ahora no se ha empezado a comprobar la eficacia de la utilización de smartphones y/o tablets como herramientas de medida en experiencias prácticas en el aprendizaje de la Física por parte del alumnado.…”