:o newb here.
Can a uno or mega communicate with one or more (10-15 or more) pro mini/micro using the tx/rx pins?
My thoughts are as follows...
One uno or mega (more input pins) controlling many minis/micros with a four wire daisy chain style setup.
I want the uno to be the master that sends a quick easy code down the line that all the minis receive at the same time. Each mini reads the code and decides if it recognizes it, then does the appropiate task. Each may have 1-5-10 tasks they are programmed to do, but only the mini that that does that task responds.
OK so, you push button 'light number 5' uno reads pin 8, uno sends code '58239' down the line. All the minis read the code, only mini 7 recognizes the code, and turns on pin 5 clicking relay 5, turning on light 5.
I know, sounds confuzzling but it makes sense if you get really high and don't think to hard.
I want only 4 wire cord to run the distance. Power, ground, tx, rx...
Also, is there sensors/senders for fiber optic for arduino? That would mean two wires and optic to do it all.
Probably not. Serial is not really intended to daisy chain. It's more point to point. However, with a slight modification, your idea may still work. The Hardware for I2C is different. They are intended to daisy chain. You would make one Arduino the master and the others are slaves. The protocol would probably also be changed a bit. Each Card has it's own address. So instead of sending the same command to all the Cards and most of the Cards ignore it, you say "Hey Card 3, Execute Command 27". Only Card 3 will receive the command and the others will have mute ears.
You can easily connect one Serial TX to several seria RX pins and they will all receive the same data. (If you have many RXs you will probably need to boost the signal power). You can include an identifier as part of the message so that each receiving device can know which messages to ignore.
Things only get complicated if you want to connect several RX pins to one TX pin. It is technically possible using diodes to isolate the signals from each other. But you will also need a system to ensure that only one TX transmits at any one time.
...R
Serial Input Basics