I don't know about a script. But I've done this many times with eventing.
Here's how:
Create the item which scans, making it call a common event.
Inside the common event, turn on a switch.
Make a second common event activated when that switch is on.
Everywhere you place this 'findable' item on the map, give the event a page with an icon marking it's location when the same switch is on.
When I did this, I made a blank text box appear on the second common event, and set the switch to turn off when the text box was closed by player input.
I've been thinking of making a tutorial on how to do this for a long time. It's really cool, and really easy. Anyway, if you have any questions about it, just hit me up and I'll explain it further.
EDIT: I just made a tutorial on this subject. You can check it out over here:
http://www.rpgmakervx.net/index.php?showtopic=48177