Arcane Clock

An image resembling and hourglass, clock face, or other timekeeping device appears on the surface you touch. Upon casting this spell, you set the spell's duration up to a maximum of 12 hours. For the duration of the spell, the image is animated in a way to represent the remaining duration of the spell. 

When the spell's duration comes to an end, the image begins flashing and a chiming alert audible within 30 feet plays for an additional duration of 1 round before the image and sound fade away.

This spell can be ended early(without triggering the chime) as a bonus action by anyone by touching the image and speaking a command word assigned during casting.