AD&D

Wizard spellLevel 1

Alarm

School
Abjuration, Evocation
Range
10 yds.
Components
V / S / M
Duration
4 hrs. + 1 ⁄2 hr./level
Casting time
1 rd.
Area of effect
Up to 20-ft. cube
None
Source
PHB

Flavor

The caster traces a ward over a doorway or patch of floor; anything crossing it unbidden sets off a sharp ringing only the protected area produces.

Mechanics

Wards an area up to a 20-ft. cube for 4 hrs. + 1/2 hr./. Any creature larger than ~1/2 cubic foot / ~3 lbs entering, touching, or crossing the warded zone without speaking a caster-set password triggers a loud ring audible within 60 ft (reduced 10 ft per closed door, 20 ft per solid wall). Ethereal/astral creatures don't trigger it; invisible, flying, levitating, gaseous, or incorporeal ones do. Caster can dismiss with a word. : a tiny bell and fine silver wire.