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Heat sensitive sensor Direction detector

2014-11-15 18:24  
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The sensor has a throughput detection device with several throughput detection membranes perpendicular to the flow, each with heating sections  and temp. detection sections.The longer side of each membrane is at least twice that of its shorter side and the longer side extends along the flow direction to be measured. A heat-sensitive sensor can be used to construct a direction detector. Such a sensor reacts to all animal heat. The one used in this design has a sensitive surface that has been divided into two. It, therefore, makes a difference, whether the heat approaches from the left or the right. The indication for cold objects is, of course, exactly the opposite. Circuit IC1B forms a symmetric supply. Terminal s of the sensor is its output. The signal at s is amplified in IC1A by a factor of about 70 before it is available at the output of the detector. To obtain good directivity, it is best to place the sensor behind a single narrow slit, rather than behind the usual raster of a multifacetted mirror. The circuit draws a current of only a few mA from a 5-V supply. Electrical output is a function of the rate of change in detector temperature rather than temperature itself. This characteristic is one of the reasons why pyroelectric sensors are widely used as thermal motion detectors.

Thermally Operated Direction Detector