I know this is somewhat of an odd question, but I'm curious about whether or not a small (or maybe matching*) voltage on a wire can represent a closed switch.
** more about this in a moment*.
First of all, take a look at this terribly simple (and poorly drawn illustration) of my garage door opener set up.
Okay, so when I press the wall switch button the circuit is closed and the garage door opener is activated.
Here's what I'm curious about:
If I took the ground (neutral) wire and plugged it into a bread board and applied 5v directly to that wire, would the garaage door activate? Would that represent a closed circuit to the system? Is that dangerous to do? I would think not, since it is only 5v.
Not Mains Power
Also note, those wires represent just the activating switch, not the mains power. That's why even though this is connected into a US home (wired as 110v) the line shown is only about 5v.
I know I could attach a relay to a bread board, then connect both the hot and ground to the bread board through the relay (via NO) and then apply voltage to the relay thus closing the relaying switch and completing the circuit.
However, I'm wondering if in this case (low voltage) if you could just apply 5v to the ground to simulate the circuit closing.
I'm not sure if what I am saying is dangerous or there is another way to do this or if the answer is simply use a relay and forget about other methods.
EDIT - Added another diagram and more notes
So imagine that the bread board in the diagram is used and the ground is now connected to another power source of 5v. Now I can apply the 5v from the other location or I can close the original switch. Can you explain why this is a problem? A short when both are on maybe? But if they were guaranteed to only be one on at a time would it work?
Edit 2 - added schematic
Okay, take a look at the schematic. We're talking about the momentary switch section. It's 12v. That's fine, change my diagrams above (in your head) to 12v. :)
There are comments that say "don't do it!!!" That's fine, I believe you, but can you explain why or why not? And don't just say, "you'll die!" :)