Infrared remote control light switch circuit (3)

The infrared remote control lamp introduced in this example does not require a separate infrared light emitter. It
can be controlled by using any existing infrared remote control at home, such as TVs, nVI machines, audio equipment, etc.
To control the turning on and off of the electric light, the circuit of the infrared remote control light is shown in Figure 21 3. The circuit
consists of an infrared sensor, an infrared light amplifier, a transmitter, an IU inverter and a power circuit.
    We know that infrared remote controls such as Wu-Lun TVs and DVD players all emit infrared light containing
: i0-, Okfiz's pulse modulation signal string. Although the encoded signals are different, we do not need to master the
encoding. And as long as the remote control sends out the initial pulse.
    When infrared receiving_pole tube VI. When receiving the infrared light from the remote control, the infrared light signal is converted
into the corresponding electrical signal, which is coupled to the infrared tlc through G. The input terminal IN of the 7 detector A1 is decoded and purified by the internal
circuit . , "set fire" and clear non-infrared signals. Finally, the output terminal () UT, that is, the first pin outputs a series of
pure external pulses, which are sent to the stable trigger (, Pl terminal) composed of 1/2A through f. Make the output terminal Ql, that is,
the ⑤ pin, output a low level and maintain it for about 2s. This period of time is determined by the time constant of R. If you change
the value of G or R, the length of the time can be shortened. A2 The other half forms a bistable circuit.
The low-level signal output by pin ⑤ is directly sent to the CP2 terminal of the bistable circuit, which is pin 0, causing the bistable circuit to flip, and
its output terminal Q2, or pin ◎, becomes low. Cow changes. If the original low level becomes high level, VT is turned on, the relay K is closed, its moving contact kl is closed, and the light E lights up. When you need to turn off the light, just press the infrared remote control
again
, the ⑨ pin of A2 suddenly changes from high level to low level, VT is cut off, the contact kl jumps open, and the light E
goes out.
    The purpose of setting the monostable trigger in the circuit is to broaden the pulse, because the tr external remote digging is required In order to change the fast single tone pulse emitted by the device
into a longer logic pulse that is easier to handle, the pulse stretching technology must be implemented, that is, time
delay. Once the VI receives the infrared signal, the monostable trigger is basically locked. Keep the output low level long enough
to prevent pulse input. Only after this period of time, the monostable trigger can continue to receive and process
infrared signals. In other words, transmitting the first infrared remote control signal can cause the subsequent two The stable circuit flips once and the light status
changes once. After transmitting a remote control signal, you must wait 2s before transmitting the signal again to make
the circuit flip again.
    VI, you can use PH302 type and other infrared receiving diodes, [requires CC1 Type high-frequency ceramic capacitor, K
Town. IZL 22F, D [I5V ultra-small low-power electromagnetic relay, no special requirements for other components. This circuit
  generally does not need to be used for any tests, it can enter normal operation, maximum control The distance is about iOm.