Household multi-channel infrared remote control circuit b

Nowadays, in families, there are multiple remote controls for color TVs, air conditioners, and stereos. How great would it be if one remote control controlled multiple electrical appliances? This circuit can
control multiple household appliances at the same time. The circuit is simple, reliable, energy-saving, and easy to make. The remote control distance is more than 8m.
    How the circuit works. This circuit consists of two parts: transmitting and receiving, as shown in Figure 18-30.
    1) Transmitting circuit: The transmitting circuit is shown in Figure a, with LC2190 as the core. It adopts a dual-in-line @-pin plastic packaging structure and contains
an encoder, modulator, etc. In the transmitting circuit, S1-S6 are coding switches. When the switch is pressed, different coding
methods are formed inside the integrated circuit, which can generate 6 binary codes. Among them, S1 and S2 are continuous emission modes. S3-S6 are single launch modes. According to the connection method in the figure,
after adding VD1 and VD2, Sl and S2 will also become a single transmission mode. C2 is the pulse interval timing capacitor, which determines
the time interval between two transmissions of remote control information. The compiled binary code further modulates the internally generated 38kHz square wave. The modulated coded signal is output by IC1① pin
, amplified by VT1, and then emitted by infrared light-emitting diode LED1. C2, RP and internal integrated circuit form a 76kHz oscillator. The 76kHz signal
is divided internally to obtain a 38kHz signal. It can be seen that adjusting RP can change the carrier frequency. When the integrated circuit is in the emitting state,
it also drives the light-emitting diode LEDZ for luminous indication. R3 is its current limiting resistor.
． z) Receiving circuit: As shown in Figure b, the receiving circuit uses 'LC2200 as the core. The coded signal emitted by the remote control
is processed by the infrared receiving circuit CX20106 and sent to the LC2200 decoding output to control each load. CX20106 contains limiting amplification, band-pass filtering, detection,
integration and shaping circuits. IJC2200 contains circuits such as amplitude amplification, color shaping, decoding and error recognition. In the receiving circuit, the modulated
coded signal is received by the gt external receiving tube LED3 and sent to the inside of CX20106. , after IC internal limiting amplification, detection, and integration. After shaping
, the IC2⑦ pin outputs a coded signal consistent with the transmitter, with the 38kHz carrier removed. Brother and G constitute the negative feedback loop of the internal preamplifier
, (is the detection capacitor. Ca is the integrating capacitor, used to filter out the 38kHz carrier signal and its harmonic components. The
encoded enters the decoder IC3⑩ pin, After internal shaping and decoding of 1C3, it is restored to 6 signals, which are output by terminals A to F respectively.
The outputs of A to F have two modes: self-locking and interlocking, which can be selected by using the M terminal of ⑩ pin. When M When connected to VI, it is an interlocking mode, that is,
A to F can only have one output at the same time; when M is connected to ground, it is a self-locking mode, that is, the output terminals of A to F form independent switches. This circuit only
draws one output output, the rest of the output circuits are exactly the same. Everyone can choose the corresponding number of output channels according to actual needs. When C outputs a high level,
the high level drives the light-emitting diode LED4 to illuminate, indicating that the remote control signal is received. At the same time, use VT2 is turned on, relay K is powered
on, the normally open contact is closed, the power socket has power, and the electrical appliances connected to the socket start to work. Until the remote control switch S3 is pressed again, the C output
end returns to low level. VT2 is cut off, K is released, and the electrical appliances stop working. In order to control multiple electrical appliances, several more power sockets Xl, X2...
X can be connected in parallel.