How to connect more than one arduino serial port together The idea is to connect more than 1 arduino slave to master as shown in schamatic



simulate this circuit &ndash; Schematic created using CircuitLab
The problem is TX slave can not just combine to master RX.
It need to done some trick like tri-state buffer to make slave TX one at time.
Anyway, avr port can config as tristate buffer.
(Q1)Is there any software solution to done this?
Second If I connnect TX to RX for half-duplex communication (using 1 data line). How to make Rx stop listenning to its self while transmiting data?
You can do it with two diodes and a resistor:



simulate this circuit &ndash; Schematic created using CircuitLab
You'll still have to implement some system to prevent collisions, but electrically that will be sound.