USB show stop button

Hi all, so I have a show stop macro made and working but I am wanting to trigger it from a “big red button” The sound department have one so we are all a little jealous and thought we would copy. 

I was wondering if it is possible to just plug a USB emergency button into the desk? If it isn’t possible what would I need to carry this out but if it is possible how would I go about triggering the macro from that button? 

Thank you.