Arcane Spotter

You create a Small, invisible observer that acts as a warning system.

Choose a point within range - the invisible observer is created in the space you choose. A creature that can see objects and creatures that are Invisible (such as through the use of the True Seeing spell) sees a luminous orb about the size of your eye, which cannot move from its space.

Until the spell ends, you become aware of any creature's presence within 20 ft. of the observer, but only if you are on the same plane of existence as it. As a bonus action, you can choose to see what the observer sees, and hear what it hears - during this time, you are Blind and Deaf in regards to your own senses. You can choose to revert to your own senses with another bonus action.

While looking through the observer's senses, you can choose to cast a spell of 2nd level or lower as if you were in the observer's space - when you do, this spell ends.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the level of spell you can cast through the observer increases by 1 per level of slot above 3rd.