I have a push button switch that is single-pole, that I need to independently control two circuits. The button will be connected to a digital pin of two different microcontrollers. So its a low current application. Unfortunately, in this case, a two-pole button cannot be used. Is there a way of doing this?
Obviously the first that springs to mind is opto-coupling, however, there is a chance that one circuit is not powered, which would mean there is a chance the opto-coupler is not powered.
It cannot be guaranteed that these two circuits share the same power supplies, hence the complications. Technically the two circuits should be +5V, however the grounds aren't necessarily common.