An electrical engineer has created a replica of the magical hammer belonging to the Marvel Comics superhero Thor, and he has succeeded in making it so that only he is "worthy" to lift it up, using electromagnetics and biometrics.
Thor is a god of thunder from Norse mythology who is also seen in Marvel Comics and the Marvel Cinematic Universe films as a superhero from the fictional realm of Asgard. After disobeying the orders of Odin, the king of Asgard, Thor (played by Chris Hemsworth) is stripped of his superhuman powers and exiled to Earth to live as a mortal, accompanied only by Mjölnir, a hammer protected by an enchantment that allows only the worthy to wield it.
Although occasionally someone else can pick the hammer up, such as the being Vision in Avengers: Age of Ultron, for the most part, no one is considered to be "worthy".
But now Allen Pan, an electrical engineer who runs the YouTube channel Sufficiently Advanced in the US has managed to build a real Mjölnir that absolutely refuses to budge if anyone other than Pan tries to pick it up.
To make it work, Pan's version of the hammer includes a microwave oven transformer electromagnet in the head of the hammer, which uses electricity from four 12v SLA batteries to produce a powerful magnetic field. The handle of the hammer, meanwhile, contains a capacitive touch fingerprint sensor attached to an Arduino Pro Mini microcontroller and a solid state relay.
If anyone other than Pan tries to pick up the hammer, the fingerprint sensor will trigger the solid state relay to turn the magnets on. The magnets then exert magnetic pull so strong that when the hammer is placed on a heavy metal surface that cannot easy be lifted, such as a locked manhole cover, it is impossible to lift the hammer up.
However, if Pan tries to pick up the hammer, the fingerprint scanner will authenticate that it is him and the magnets will turn off, allowing him to lift the hammer immediately.
Pan took his Mjölnir to Venice Beach in California, where he challenged regular people and Muscle Beach bodybuilders to prove their "worth". As the video below shows, his invention certainly makes for a very entertaining prank: