Abstract: A signal current I1 that is output from output terminal of semiconductor position detection element is converted to a signal voltage V1 by a current/voltage conversion unit and a signal current I2 that is output from output terminal is converted to a signal voltage V2 by a current/voltage conversion unit. Signal voltages V1 and V2 are compared in magnitude by a comparison circuit and a comparison signal is output so that maximum signal Vmax and minimum signal Vmin are selected. In A/D conversion circuit, the A/D conversion range is set using maximum signal Vmax, and minimum signal Vmin is converted to a digital signal and output. The position of beam incidence on semiconductor position detection element is found by incidence position calculating unit using the comparison signal and digital signal.

Abstract: An occupant sensor has a photodetective portion having a photosensitive surface capable of receiving a reflection R of a light curtain (two-dimensional light) projected from a light projecting portion. Masks cover part of the photosensitive surface. The apparatus can quickly detect presence/absence of an occupant, because the masks block entry of unwanted light. Control of an airbag is carried out based on the presence/absence of occupant.

Abstract: A signal current I1 that is output from output terminal of semiconductor position detection element is converted to a signal voltage V1 by a current/voltage conversion unit and a signal current I2 that is output from output terminal is converted to a signal voltage V2 by a current/voltage conversion unit. Signal voltages V1 and V2 are compared in magnitude by a comparison circuit and a comparison signal is output so that maximum signal Vmax and minimum signal Vmin are selected. In A/D conversion circuit, the A/D conversion range is set using maximum signal Vmax, and minimum signal Vmin is converted to a digital signal and output. The position of beam incidence on semiconductor position detection element is found by incidence position calculating unit using the comparison signal and digital signal.

Abstract: An occupant sensor has a photodetective portion having a photosensitive surface capable of receiving a reflection R of a light curtain (two-dimensional light) projected from a light projecting portion. Masks cover part of the photosensitive surface. The apparatus can quickly detect presence/absence of an occupant, because the masks block entry of unwanted light. Control of an airbag is carried out based on the presence/absence of occupant.

Abstract: The smoke detecting apparatus of the present invention comprises a detection space (52) into which generated smoke is to be introduced; light-emitting means (2) for emitting a predetermined coded light pulse train into the detection space (52); light-detecting means (3) for detecting scattered light which is generated when the light emitted from the light-emitting means (2) is scattered by the smoke and generating an electric signal corresponding to the detected light; and control means (4) for generating a burst code signal composed of a pulse train coded with a reference pulse to the light-emitting means (2) and judging that the smoke exists in the detection space (52) when the pulse patterns of thus compared signals coincide with each other. According to this configuration, the apparatus can securely operate at the time of smoking and cannot detect when there is no smoke.