The sensor is designed for electrical control or to work with the security system. He reacts to it humans or approximation in any subject. Depending on the spotted Noah trimpot sensitive range of activities triggering can be from a few metres to a few centimeters.
Schema based on lies LM567 chip that represents the dimensions of the decoder. Because setting the frequency decoding depends on the frequency of a built-in generator, and in fact it is equal, you can use this frequency as pulse modulation source of infrared radiation.
The frequency of a built-in generator micro schemes depends on RC circuits R7-C2. When the pulses can be removed with the withdrawal of 5 chips. That here and done. Pulses with 5 output A1 through R4-C3 comes to the input of the amplifier to VT1 and VT2 zistorah Tran, the output of which (in the reservoir chain VT1) included infra red led HL1.
Thus, the IR emitter serves HL1 and the receiver phototransistor is VT3.
HL1 и VT3 взаимно расположены так, что, прямой оптической связи между ними нет. Они направлены в одну сторону, – в ту сторону, и между ними имеется непрозрачная перегородка, в качестве которой может быть, например, столешница стола (например, HL1 на столе, а VТ3 под столом).
Если перед датчиком, состоящим из HL1 и VT3 появляется человек или какой-то предмет, ИК-луч, излученный светодиодом HL1 отражается от его поверхности, и попадает на фототранзистор VТ3. Так как луч был модулирован импульсами от генератора микросхемы А1, то на эмиттере VТ3 образуются импульсы фототока такой же частоты. Они через подстроечный резистор R6, регулирующий чувствительность, и конденсатор С1, поступают на вход декодера микросхемы А1. Так как по частоте они совпадают с частотой генератора на R7 и С2, а иначе и быть не может, открывается ключ на выходе микросхемы А1, он выходит коллектором на её вывод 8. Это создает ток на базе транзистора VТ4. Он открывается и напряжение на его коллекторе поднимается до напряжения питания.
If a sensor consisting of HL1 and VT3 appears a person or some object, infrared ray, rejected House led light reflected from its surface HL1 and hits the phototransistor VT3. Because the beam was modulated pulses from the generator chip A1, then the emitter VT3 formed impulses photocurrent of the same frequency. They through trimmer resistor R6, governing sensitivity, and capacitor C1, arrive at the entrance of the decoder chip A1. Because they coincide with the frequency generator frequency on R7 and C2, and it could not be otherwise, the key is opened at the exit of the A1 chips, it goes black, a lecturer at the output 8. This creates a current of transistor-based VT4. It opens and the voltage on its manifold rises to power.
IR-led domestic production production AL 123 and you can replace virtually any IR led timer, were received for remotes remote systems remote control.
Nominal value of R7 and C2 may differ materially from those indicated in the diagram. To work practically it sensor has no effect, because the same chain R7-S2 works as a reference frequency generator for the phase detector A1 chip decoder and generator for modulation infrared LEDs. That is, the transmit and receive frequencies in any case are the same, because the heat were one and the same generator.
All applied capacitors shall be designed for maximum voltage supply voltage not below the proposal.
The sensitivity of the sensor (the range of response) can be adjusted in two ways. In the first case, this trimmer resistor R6 is the sensitivity of the decoder. In the second case, this selection of resistance rezis Tora R5, which limits the current through the infrared led. Choose this resistor is less than 3-4 Ohms.
Literature:
- Two machine control lighting on Czech television. g. Radio, 2008, no. 3, p. 37.
Author: Gorchuk N.v.
