Multiple signals to same pcb?

Joe,

Is your intent to push button #1 and have LED #1 light up, and/or press button #2 and have LED #2 light up?  What exactly are you trying to accomplish?

Maybe I can just cut that little resistor and make the common wire +5v for all and then put my own resistors from the signal wires to ground for each of them?  Thanks again.

If I connect the common wire to 4 different arduino pin signal wires, then is that problem? Reason being they may be active at the same time, so having two signal wires connected to the same circuit and each signaling at same maybe time burn something out?

you may have something like this (Based on description)

hope this helps

did you make the board yourself and are having difficulty getting it to work or is it a bought product?

can you provide a picture or a schematic like the one i just provided but showing how you have the parts connected

thanks

oh and post your sketch so we can see what your trying to do in the code as well

I was going to mention the resistors on the switches because I didn't recall Joe mentioning them in his first post, but I stepped away to eat some chicken pot pie instead.

What app are you using to make your whiteboard drawings, Peter?  Something on a surface I take it?  I don't suppose there is a copy cat app for my iPad.  I like it.

The board was connected to another proprietary computer that I am trying to replace.  Right now it is like the diagram below, and I can connect one led to a pin, e.g. pin 12, as shown.  If I switch the wires, so the common wire is ground, then the led doesn't work.  Actually now that's making me think those are diodes, and not resistors.  Regardless, what I don't know is if I can connect the Pin12 wire to Pin11 also, and then both the other wires to ground, or that zap something.  I'm thinking now the safest thing is to just cut the pcb and separate everything and solder new wires to make 4 separate circuits.

It would help to know what you are intending for the two buttons and two LEDs to do.  I think you are definitely going to need to re-wire the board.  As drawn, the schematic, to me at least, looks wrong.  Can you get us a picture of the existing PCB, preferably both sides?  Maybe we can give you direction on what needs to change to make it work.  LEDs are diodes and they only work in one direction.  If you look carefully at the Light Emitting Diode, one side of it should be flat.  That side is the cathode and it should go to ground and on one side or another you need a resistor, otherwise the LED can go POP.  The resistor should be about 560 Ohms in a 5V circuit for an LED.  There is an excellent book by Massimo Banzi "Getting Started with Arduino".  You might want to check it out.  He has a few examples that would be helpful for you.

Looking at those diodes, the only way I could see that board working is by connecting the common wire to GND.

Here is the board.

But I am looking at Mike's led pic and thinking maybe I didn't understand how leds work, which is to say that full current doesn't flow through the led, if at all, but current flows more around the led so to speak and stuff happens between the two sides and the resistor limits the current going around the two sides so not too much stuff happens between the two sides or poof?  So they are resistors and they aren't in parallel, they just look like they are.

So getting back to my original question, thinking now even if bad stuff doesn't happen between the arduino pins, it's moot because both leds would light up on either signal because arduino has individual positive and common ground, whereas the proprietary computer this board was connected to clearly has individual ground and common positive.  That means I either have to turn the led's around to change the common to ground or cut this thing and add more wires.

Anyway, anyone feel free to correct me if any of that sounds wrong.  Also any ideas are welcome.

Thanks again for all your help!