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Photovoltaic (PV) energy harvesting is commonly used to power autonomous devices, and maximum power point tracking (MPPT) is often used to optimize its efficiency. This paper describes an ultra low-power MPPT circuit with a novel sample-and-hold and cold-start arrangement, enabling MPPT across the range of light intensities found indoors, which has not been reported before. The circuit has been validated in practice and found to cold-start and operate from 100 lux (typical of dim indoor lighting) up to 5000 lux with a 55 cm2 amorphous silicon PV module. It is more efficient than non-MPPT circuits, which are the state-of-the-art for indoor PV systems. The proposed circuit maximizes the active time of the PV module by carrying out samples only once per minute. The MPPT control arrangement draws a quiescent current draw of only 8 μA, and does not require an additional light sensor as has been required by previously reported low-power MPPT circuits. [ABSTRACT FROM PUBLISHER]

The article reports that technology company Apple has admitted that Apple admitted the heart rate monitor on the Apple Watch, which uses a light sensor, may not work for people with arm tattoos and can also impact heart rate sensor performance.

The article offers information on the Dartmouth College researchers who are experimenting smart spaces using light to transmit data. Topics include the integrated-visible light communication (iVLC) project, the smart spaces that feature an interplay of algorithms, ceiling-mounted light-emitting diodes (LEDs)and light sensors, and the statement of Xia Zhou, principal investigator of the project, regarding the importance of the ubiquity of lights.

The article focuses on the study conducted by the provider of software application IHS Inc. increasing demand for Light and proximity sensors in mobile handsets and tablets developed by maker of consumer electronic products Apple Inc. and Samsung Electronic Co. IHS refers to various sensors such as ambient light, RBG and proximity. Marwan Boustany, an analyst at IHS, states that the sustained growth in sales of smart phones and computer tablets augurs well for the future of light sensors.