zza ni |
a lot of these traps default back to the 'Alarm' spell, which by itself doesn't roll perception. it auto find anything not 'Ethereal or astral'.
but the size and such do normally work the same:
"it thereafter sounds a mental or audible alarm each time a creature of
Tiny or larger size enters the warded area or touches it. A creature that speaks the password (determined by you at the time of casting) does not set off the alarm."
id go with the same if asked - any tiny or bigger creature that enter set it off (so cats yes, bats\mice no). if it gives a perception check it goes vs the stealth of the target (in case the target try to hide, remember invisible get +20 if moving and 40 if not etc)