In Marvel comics, Thor’s legendary hammer Mjolnir is famous for being able to be wielded only by the worthy (Captain America is a little worthy). For the unworthy, literally everyone except Thor, the Mjolnir simply cannot be lifted off the ground.
It is this property that electrical engineer Allen Pan, aka Sufficiently Advanced on YouTube, decided to replicate in his very own take on a “working” Mjolnir.
To make the hammer immoveable Pan utilised an electromagnet inside the head of the Mjolnir, salvaged from a microwave oven transformer. This creates a strong magnetic field such that when placed on a metal surface, pulling on it will make it seem to heavy to lift.
The handle is attached to a capacitive touch sensor, which in turn is attached to an Arduino Pro Mini and a solid state relay, which serves as a switching device. As soon as someone grasps the handle, the electromagnets switch on, attaching the hammer to the metal surface.
However, the hammer can be turned off via a fingerprint sensor keyed to Pan’s thumbprint. When Pan grasps the hammer, the magnets switch on. When he moves his thumb over the sensor, it switches off again, allowing Pan to lift the hammer.
Pan took his invention to the streets of Venice Beach, California, where he challenged unsuspecting passersby to lift it. It’s a magnificent prank… and, just like in the comics and films, there may be more than one who is worthy. Sometimes brain does beat brawn.