Dr Daniel Reardon, a research fellow at a Melbourne university, was building a necklace that sounds an alarm on facial contact, when the mishap occurred on Thursday night.

The 27 year-old astrophysicist, who studies pulsars and gravitational waves, said he was trying to liven up the boredom of self-isolation with the four powerful neodymium magnets.

“I have some electronic equipment but really no experience or expertise in building circuits or things,” he told Guardian Australia.

“I had a part that detects magnetic fields. I thought that if I built a circuit that could detect the magnetic field, and we wore magnets on our wrists, then it could set off an alarm if you brought it too close to your face. A bit of boredom in isolation made me think of that.”