Determining the efficiency of optical sources using a smartphone's ambient light sensor
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 agree-
ment 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.