A cheap and easy-to-make infrared TV signal repeater

At present, the radio and television network has upgraded the original analog signal to a digital signal, which needs to be demodulated by a set-top box before it can be viewed. Since a set-top box can only connect to one TV, if there are two TVs in a home, two set-top boxes are needed. For those that are not used at the same time, infrared repeaters can be used to share them. For this purpose, through searching for information, making, improving, and using it, the working principle is briefly introduced, see the attached figure.

The components used in this circuit are all easy-to-purchase common components with strong anti-interference, low cost, easy to make, and can work normally without debugging.

The circuit is based on the commonly used time base circuit NE555. The infrared receiving head needs to use an integrated high level in static state and a low level when receiving the remote control signal, otherwise the circuit cannot work properly. The infrared emitting diode is a common infrared emitting tube, and other components can be as given in the figure. Its working principle is that the infrared integrated receiving head receives the infrared signal sent by the remote control to control the conduction and cutoff of the Q1 tube to achieve whether the IC is powered. Once the IC is powered, it will generate a 38kHz signal by itself, and output a high level through the ③ pin to turn on Q2, and the infrared emitting tube sends out an infrared signal.

It is connected by a universal board, and can be powered on for testing after checking the circuit diagram. After it is normal, place the receiving head in the room, extend the transmitting tube with a lead to the vicinity of the infrared receiving window of the receiver, and then the set-top box can be remotely controlled.