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Infrared approach detector / sensor

2014-11-01 11:58  
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Basic operation of the monitor attached to the circuit is to detect objects (obstacles), at distances ranging from a few millimeters to and a few centimeters. Depending circuits used in industry and hospitals. The position sensor IC2 optoapomonotis used a type of Siemens SFH900 someone similar. The sign shows, led to a phase locked circuit (contained in IC1), which compares with signal frequency an oscillator which is also located within the same chip. For as long as the frequencies of two signals coincide, the pin output of IC1 (pin 8) is still reasonable 'O'.
Infrared approach detector / sensor

The internal oscillator frequency signal produces approximately 4.5 kHz, based on the time constant set netting R1-C1. The rectangular output signal at pin 5, ends at the base of the transistor T 1, whereby the anathosthinei same frequency as the LED's optoapomonoti. Provided that the LED flashes reflected in a barrier and are captured by the phototransistor, the input pin 3 of IC 1 receives a signal, the frequency of which compares with that of the integrated oscillator. If two frequencies are identical, the output of IC 8 is driven to logical 'O' and the LED L1 fototholei. Otherwise the case, the output remains at '1 '. The use of phase locked loop (RLL) guarantees that the circuit is insensitive to diffuse light or any kind of spurious flashes from other light sources. The detector's sensitivity is adjusted via the P1 and the requirements of a stream (if usedMaterials marked) ranging between 10-30 mA. In place of optoapomonoti you can place different types of components corresponding or even a pair of LED and phototransistor. In the latter case you should note that the phototransistor to receive the light of LED only through reflection and not directly. Between the output of IC 1 and ground, you can put a solid-state switch (SSR, Solid State Relay), which is able to supply loads with higher requirements. Remember that the current that can absorb the spike 8 reaches 100 mA. If your design needs require the maximum output current, remove the LED D1.

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