A daylight sensor for automated window-shading applications that incorporates at least one (and optionally more than one) of three aspects: an optimized Field-of-View (FOV), angle-diversity sensing (via at least two sub-sensors with different FOVs, whose outputs are processed in a particular way to yield the overall sensor output), and multi-spectral sensing (via at least two sub-sensors with differing spectral responses and, optionally, different FOVs, whose outputs are processed in a particular way to yield the sensor output). These aspects improve the correlation between the sensor output and the subjectively-perceived daylight level (especially under glare-inducing conditions, such as in the presence of low-angle direct sunlight), thereby enabling more effective automatic control of daylight admitted into a room.

Embodiments of the present disclosure are directed toward techniques and configurations for a photonic apparatus with a photodetector with bias control to provide substantially constant responsivity. The apparatus includes a first photodetector, to receive an optical input and provide a corresponding electrical output; a second photodetector coupled with the first photodetector, wherein the second photodetector is free from receipt of the optical input; and circuitry coupled with the first and second photodetectors, to generate a bias voltage, based at least in part on a dark current generated by the second photodetector in an absence of the optical input, and provide the generated bias voltage to the first photodetector. The first photodetector is to provide a substantially constant ratio of the electrical output to optical input in response to the provision of the generated bias voltage. Additional embodiments may be described and claimed.

An optical measurement device includes a light source, a first detector, and a second detector. The light source emits light to a measurement site of a patient and one or more detectors detect the light from the light source. At least a portion of a detector is translucent and the light passes through the translucent portion prior to reaching the measurement site. A detector receives the light after attenuation and/or reflection or refraction by the measurement site. A processor determines a light intensity of the light source, a light intensity through a tissue site, or a light intensity of reflected or refracted light based on light detected by the one or more detectors. The processor can estimate a concentration of an analyte at the measurement site or an absorption or reflection at the measurement site.

Certain aspects pertain to a cloud detector comprising a first detector module directed to a first region of the sky and a second detector module directed to a second region of the sky. Each detector module has a tube enclosing one or more sensing elements. The one or more sensing elements of the first detector module are configured to take weather condition readings from the first region of the sky. The one or more sensing elements of the second detector module are configured to take weather condition readings from the second region of the sky. In one aspect, the cloud detector is configured to detect cloud cover based on these weather condition readings. In some cases, the one or more sensing elements comprise an infrared radiation detector (e.g., thermopile) for measuring infrared radiation intensity and a photosensor element for measuring sunlight intensity.

A semiconductor device comprising a plurality of photoelectric conversion elements arrayed on a substrate, a readout unit configured to read out signals from the plurality of photoelectric conversion elements, and a light source unit driver configured to drive a light source unit, wherein the plurality of photoelectric conversion elements include a first element configured to receive incident light and a second element configured to be shielded from the incident light, and the light source unit driver drives the light source based on both a signal from the first element and a signal from the second element read out by the readout unit.

An optical apparatus includes a first light receiving unit including a first avalanche photodiode, a second light receiving unit including a second avalanche photodiode whose light receiving surface is shielded from light, and a voltage control unit configured to apply a first reverse bias voltage to the first avalanche photodiode and a second reverse bias voltage to the second avalanche photodiode. The voltage control unit controls the first reverse bias voltage based on the second reverse bias voltage.

A technique and apparatus for monitoring a plant canopy over a field is disclosed. The technique includes receiving first sensor values from a plurality of plant canopy sensors disposed in or on a ground of the field under the plant canopy. The first sensor values are indicative of near-infrared (IR) light reflected or reradiated from the plant canopy. Second sensor values are also received from the plant canopy sensors. The second sensor values are indicative of red light that is incident through the plant canopy. A map of the plant canopy may be generated based upon the first and second sensor values.

An apparatus containing an optical emitter configured to emit optical radiation is provided. Further, the apparatus includes a first hermetically sealed measurement cell filled with a first gas. The first gas is configured to absorb the optical radiation at least partially at one or more predetermined wavelengths. Additionally, the apparatus includes a first microphone arranged in the measurement cell and configured to generate a first microphone signal on a basis of a photoacoustic excitation of the first gas by the optical radiation. The apparatus moreover includes an evaluation circuit configured to take the first microphone signal as a basis for generating a first measurement signal indicating an emission intensity of the optical emitter at the one or more predetermined wavelengths.

An example device includes a wireless charging circuit to wirelessly charge a portable electronic device. The device further includes a first photosensor positioned within an effective charging range of the wireless charging circuit, the first photosensor to output a first signal, and a second photosensor positioned outside the effective charging range, the second photosensor to output a second signal. The device further includes a control circuit connected to the wireless charging circuit, the first photosensor, and the second photosensor. The control circuit detects the portable electronic device positioned within the effective charging range of the wireless charging circuit by detecting a difference between the first signal and the second signal. The control circuit turns on the wireless charging circuit in response to detecting the difference. The control circuit turns off the wireless charging circuit in response to detecting that the first signal matches the second signal.

A system and method with AC coupling that reserves photodiode bandwidth in a biased configuration, allows optimal transimpedance amplifier performance, retains DC signal measurement capability, and does not introduce noise into the balanced detection signal.