How to use a wire to transmit a signal to an IR receiver?

Question

Arduino

I have the following diagram.
How can I directly transfer the signal from arduino A to arduino B? Allegedly, this receiver caught the IR signal. Yes, I know, you can make an IR diode, but I'm interested in using a wire

Answer 1

Well, firstly, connect the earth, and secondly, add a current-limiting resistor so that the diode and the dunya do not burn each other. and try to send

Answer 2

1. The scheme is finally nonsense. You are trying to connect an IR receiver to two Arduinos at the same time, while only B will receive a signal.
2. If you want both to receive a signal, connect the GND pins on both boards. Although this is stupidity.
3. If you want the boards to communicate with each other via IR, then you must have a separate IR emitter and IR receiver on each board. Although this is also stupidity, with the exception of rare cases.
4. If you want "by wire" then you have at least 4 options:
1) UART . The simplest option, but it is used in programming. Therefore, before uploading the sketch, the connection must be disconnected
2) Software UART. The principle is the same, but it will take CPU time and memory. But you can assign any conclusions.
3) SPI . consumes a lot of output.
4) I2C Personally, I think that this is the most acceptable option