Could it be that the internal pullups are now not enough?
Could it be that the internal pullups are now not enough? The copper path is actually copper pipe, over 4 meters of it, so it is one big ol' conductor.
I just wondered if it might be a potential case before I go meddling.
Just a thought, but is the ring insulted where the person is touching it? It may help to isolate the person (big ol' antenna) from the ring.
I agree, the reason why I asked is because the whole thing is soldered onto one of those proto strip boards and they're horrible to work with; shorts etc.