Eltab
Lord of the Hidden Layer
Put the mechanism of the trap inside the wall, construct a 3" thick lead panel in front of it, and place a normal façade in front of that, aligned correctly with the rest of the wall as the PCs see it.
Any spell will fail to find what is hidden behind the lead. Now you just have to be an artisan in the construction and home decoration industries, to fool mortal senses.
Any spell will fail to find what is hidden behind the lead. Now you just have to be an artisan in the construction and home decoration industries, to fool mortal senses.