Bringing up an aspiring engineer? The KidzLabsMetal Detector Robot Kitmight be a perfect gift for them.
You need to build the robot from part by part, including gears and electrical wiring. Don't worry though - there's a detailed manual to help you. And when it's all assembled, you can bring it to life with a pair of googly eyes.
The robot rides back and forth, and you can control it with a wired remote. When it comes across anything metal, it lets you know with characteristic beeping.
You can detach the detector for a hand-held mode and go exploring for metals around the house or outdoors.