Tiny flashlight so they can read in the dark when their parents think they’re asleep OR they can read top secret documents in secret!
Invisible ink that can only be read with the UV light they build so they can either pass notes in class and not get caught OR they can record top secret messages and pass it to other spies!
An alarm system to guard their bedroom or diary drawer from their little brother OR can act as a deterrent to protect top secret documents!
The first one I built a prototype for in P Comp, but I’m contemplating better designs for it. Since the second is also a flashlight, I want to ponder a little longer how to make the first two feel like truly different builds. But the third one — the alarm system — I’ve never built before so I made a first prototype.