Stone of Alarm

Wondrous item, uncommon (requires attunement)

This thumb-sized flat stone is inscribed with runes of warning. You can attach the stone of alarm to another object by concentrating for 1 minute. Once attached, if any creature other than you moves the item more than 1 foot away from you, the stone of alarm triggers an alert identical to an alarm spell.

You determine when you attach the stone of alarm whether the alarm will be mental or audible. Once the stone of alarm has been triggered, you cannot reset the alarm (either on the same object or a new object) until you complete a long rest.