You set an alarm against unwanted intrusion. Choose a door, a window, or an area within range that is no larger than a 20-foot cube. Until the spell ends, an alarm alerts you whenever a Tiny or larger creature touches or enters the warded area. When you cast the spell, you can designate creatures that won't set off the alarm. You also choose whether the alarm is mental or audible.

A mental alarm alerts you with a ping in your mind if you are within 1 mile of the warded area. This ping awakens you if you are sleeping.

An audible alarm produces the sound of a hand bell for 10 seconds within 60 feet.

Mentally defining a protected area, envision an invisible spiderweb with a central bell. Unwelcome intruders will unwittingly walk into your web, ringing the bell and alerting you to their presence.

I Cast Alarm
In my arcane tinkering, I string a wire through a bell's hanger eye. Whispering, "Ring in my mind," I name friends, ensuring the bell won't toll for them. Placing it, I enchant the area. Later, a chime might awaken me, signaling an interloper and transforming my arcane tinkering into a vigilant guardian.