Identify all items within range C#

Hi, I'm learning Unity and trying to do my first project. I've got a problem with a rather simple mechanism I want to implement:

In a top-down 2D game I want the player to be able to fire a probe (by pressing a key) that would identify all items within its range. All it needs to do is to show the labels with the names of those items above them. I want the range to move with the player (he's not dropping the probe, but is carrying it). It should only work once though - when I press the key only what happens to be within the range is identified.

I almost did it by creating a script that spawns a child object of the player. I wanted this object to have a circle collider that would activate the labels of the objects, but the collider of a child only works on the parent collider it seems.

I'd be very grateful for any help.

Thanks! All the best!