Alarm

Alarm was an abjuration spell designed to alert its caster.

Effects
The caster picked an area of no more than 20 ft (6.1 m) wide that when crossed by a creature the spell would alert the caster. When casting the spell, the caster could choose what creatures would not trigger the alarm. The alarm itself was a "ping" in the mind of the caster that would wake them if they were asleep or an actual sound that lasted for six seconds.

Components
In addition to verbal and somatic components, the spell required a material component, a small bell and a length of slender silver wire.

History
The spell was attributed to Netherese arcanist Decampus in and was originally called Decampus's alarm.