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.

Components
To cast this spell, the wielder needed a small bell and a length of slender silver wire.

Appearances

 * Player's Handbook 5th edition