In modern systems of remote control (RC) television and other equipment generally used infrared (IR) photodetectors with a specific carrier frequency. This IR receiver must restore the data from the two-phase encoding, to respond to rapid changes in signal level, regardless of interference and do not feel the ambient light. To satisfy all of these requirements is not easy.
Recently, a large widespread Three-terminal integrated IR receivers. In one case, they combine a photodiode, a preamplifier and a pulse shaper. The output signal is formed by a conventional TTL pulse without filling (36 kHz) suitable for further processing digital IC. Such receivers are manufactured by many companies: SFH-506 f.Siemens, TSOP1736 f. Leau, TFMS5360 f.Tetyu, ILM5360 production of «Integral» and others. There are several standards (protocols) control, for example, RC-5, which differ in particular carrier frequency. Developed integrated receivers for different frequencies.
In amateur designs with remote control via IR channel, you can use the TV remote control and other equipment. The main thing that was a photodetector of the same standard (protocol) as the transmitter. Given the high sensitivity of the integrated photodetectors to interference on nutrition in their supply chains should be used RC- filters.
Functions of the delay element, excluding excessively rapid change in brightness, performs counter DD1. He divides the frequency of the received pulse signal 16 such that the inlet 16 IR pulse photodetector output pulse corresponding to 1 meter. Therefore, for a complete change in brightness from zero to maximum and back have to hold the remote button down for a few seconds.
Chain VD1-C2-R3 resets the counter DD1 some time after you release the button remote that there is no overflow and its false alarm with repeated use the remote control to control staffing device (TV, stereo and so on.). When receiving a signal from the remote control output DA1 pulses occur, the first C2 discharges through the VD1 and the inner core transistor DA1. After the termination of the signal diode VD1 is closed and the capacitor C2 is charged through R3. Once the voltage across C2 reaches «1», the counter is reset DD1.
Counting pulses output from DD1 are input to the counter DD2, which together with the elements DD3.1 … DD3.4 generating circuit forms binary codewords each of which corresponds to a brightness level of incandescent EL1. Binary combination of LED displays line HL1 … HL4 and enters the resistive matrix R10 .. .R14, whose task is to form a control voltage for the pulse position in the analog dimmer unijunction transistor (VT1, VT2, C7, R15 … R18, VS1 ).
The essence of the method of pulse position brightness control is to change the date of opening of the thyristor, considering the transition from sinewave mains voltage zero crossing. The longer the delay the opening of the thyristor, the lower the brightness of the lamp, and vice versa. The desired delay for the thyristor matrix provide resistors R10 … R14 together with the capacitor C7. The greater the output voltage of a resistive matrix, the smaller the time constant of the chain (R10 … R14) -C7, and hence the greater the brightness of an incandescent lamp.
Parametric stabilizer (DA1, SOC C4) transformerless power source (VD2, VD3 VD6 …, C5, C6, R8 and R9) provided with two ballast capacitors C5 and Sb. Resistors R8 and R9 included to discharge capacitors after disconnecting the device from the network.
Some disadvantage of this machine can be considered the need for the selection of resistors R10 … R14 for smooth brightness control.
The device is assembled on the circuit board of the bilateral fiberglass dimensions 78×78 mm and fits into a standard plastic box in a network splitter device used fixed resistors Type MLT-0,125, ballast capacitors C5 and C6 in the circuit stabilizatora- type K73-17 for voltage less than 400 V, and the rest — K10-17, electrolytic — K50-35 or imported. LEDs — super-bright red and green color with a diameter of 5 mm. Zener diodes VD2 and VD11 in metal housings for voltage stabilization 9 … 12 can be of the type D809, D814B (B, D, E) or similar, diode bridges — vertical design, type RS407L. All IC series KR1564 (74NShh) are interchangeable on the corresponding analogues series KR1554 (74AShh). The integrated regulator — type KR1181EN5A (78L05).