user81859: So I have 5 Nanos all trying to crack a password, the idea is each one has one fifth of the list so they can test 5 at a time, then when it is found, I want it to be displayed on a screen I have, the idea is to connect them all to a hub which would be the arduino uno, the Uno would then take the char was sent, and send it to the screen, it does not know which Arduino will send the char and the idea is to use serial.write but I am open to other options. What is the best way to go about accomplishing this task, is there some way I can have it reading the serial from all 5 Nanos, and can this be done without it being plugged into a computer?

user7508: Presumably you will avoid having two Nanos try the same item from the
list. Then, only one Nano can find the answer, and only one will try to
transmit data at any given time. In such a situation, yes, you could
connect all five Nanos to the same serial link:

Connect the Uno's TX directly to the RX each Nano. They will all
receive the data transmitted by the Uno.
Connect the Uno's RX to the TX of each Nano through this circuit:


simulate this circuit – Schematic created using CircuitLab
As long as at most one Nano tries to Serial.print() (or
Serial.write()) at any given time, the Uno will receive the data just
fine, although it will not be able to tell which of the Nanos sent it.

81859: <p>So I have 5 Nanos all trying to crack a password, the idea is each one has one fifth of the list so they can test 5 at a time, then when it is found, I want it to be displayed on a screen I have, the idea is to connect them all to a hub which would be the arduino uno, the Uno would then take the char was sent, and send it to the screen, it does not know which Arduino will send the char and the idea is to use serial.write but I am open to other options. What is the best way to go about accomplishing this task, is there some way I can have it reading the serial from all 5 Nanos, and can this be done without it being plugged into a computer?</p>
 7508: <p>Presumably you will avoid having two Nanos try the same item from the
list. Then, only one Nano can find the answer, and only one will try to
transmit data at any given time. In such a situation, yes, you could
connect all five Nanos to the same serial link:</p>
<ul>
<li>Connect the Uno's TX directly to the RX each Nano. They will all
receive the data transmitted by the Uno.</li>
<li>Connect the Uno's RX to the TX of each Nano through this circuit:</li>
</ul>

<p><img src="https://i.stack.imgur.com/pPEaC.png" alt="schematic" /></p>

<p><sup><a href="/plugins/schematics?image=http%3a%2f%2fi.stack.imgur.com%2fpPEaC.png">simulate this circuit</a> &ndash; Schematic created using <a href="https://www.circuitlab.com/" rel="nofollow">CircuitLab</a></sup></p>
<p>As long as at most one Nano tries to <code>Serial.print()</code> (or
<code>Serial.write()</code>) at any given time, the Uno will receive the data just
fine, although it will not be able to tell which of the Nanos sent it.</p>
