Vishay has added to its optoelectronics portfolio a family of mid-range infrared (IR) sensors featuring digital and analog outputs in three package types. With a fast response time of 300 μs and low supply current of 0,85 mA, the detectors have a range of up to 30 m when used as part of an interrupter design and a range of up to 3 m when used as part of a reflective sensor.
Some object detecting sensors adjust their detection threshold depending on the amount of ambient light and optical noise present in the environment. To avoid false detections in the presence of noise, the gain of the amplifier may adjust itself to such a low level that sensor responsiveness is affected. In low ambient light conditions, the sensor may increase its gain and make the receiver too sensitive, such that it will detect and respond to reflected or stray light. The TSOP4038, TSOP58038 and TSOP5038 IR sensors with digital output eliminate these problems by featuring a fixed gain. With a fixed gain the detection threshold and resulting detection distance is fixed. Once the design of the optical parameters such as the intensity of the emitter, the aperture in front of the receiver, and the alignment of emitter and detector are determined, the sensor will have stable, repeatable performance under all lighting conditions.
Many other applications require a reflective sensor that detects not only presence but also proximity by measuring the strength or weakness of the reflected signal. Instead of a fixed detection threshold, analog information from the sensor is needed. This is possible with Vishay’s new proximity sensors. The length of the sensor’s output pulse in response to the emitter signal varies in proportion to the amount of light reflected from the object being detected. For near objects, the output pulse approaches 100% of the emitted pulse; for far objects, the output pulse becomes shorter.
These mid-range sensors enable a wide variety of safety mechanisms and automatic fixtures in homes, businesses and industrial settings. Typical applications include safety switches for garage doors, elevator doors, gates, perimeter guards and industrial light curtains, and reflective sensors for toilets, urinals, faucets, hand dryers, towel dispensers and LCD monitor power sensors.
The IR sensors provide shielding against EMI and a supply voltage of 2,7 V to 5,5 V. To simplify designs, they feature a photo detector and preamplifier in one package, while visible light is suppressed by an internal IR filter.
For more information contact EBV Electrolink, +27 (0)21 402 1940, [email protected], www.ebv.com
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