One button to control two Arduinos

Other Hardware General Electronics
1

Is it possible to use one button to send a signal to two Arduinos at the same time?

I have one Arduion Uno with a CNC stepper motor controller and one Arduino Mini Pro for temperature and LCd info on the controller box.
I would like to have buttons to send a stop, hold and reset tol the CNC controller and at the same time pick up the button actions to show on the LCD.
The two cards are not powered from the same power, so they will not have the same + and -
The Uno used for CNC is powered both with USB and the stepper controller from 24VDC.
The Mini Pro gets 7VDC power from the 24VDC via a downstepper.

The buttons have 5 pins.
+/- 24V for light
NO, NC and C
The buttons from Amazon.com

2

If the powers are different then you'll need to opto-isolate at least one of them.

3

Ok, but how do I do that.
I'm a beginner :slight_smile:

4

With an optoisolator and google search? Do some research and report back with what you think
might work and people will check you are on the right track.

5

Thnx, I'm on it :slight_smile:

6

Or use a double pole switch/button, one pole for each Arduino.

7

I allready have the buttons, so I think a 4 channel opto-isolator will work.
One like this:

8

Thats quite flexible yes - you get pull-ups on the output and transistor on the input so it
will be quite sensitive should you need it (not an issue with a push-button).

You only need one channel for your needs, choose the device that will be powered on first/last
for the button and input to the opto isolator.

9

I was thinking 1 channel for each button. 3 buttons need 3 channels?
Is it possible to let 3 buttons use only 1 channel?

10

You should use a 4pole momentary switch and connect one side to one arduino and the opposite site to another arduino..