Researchers demonstrate temperature sensor powered by nearby electrical wiring

Researchers at the University of Arkansas and the University of Michigan demonstrated a battery-free temperature sensor powered by energy captured from magnetic fields near electrical wiring, New Atlas reports. A graphene inductor with a steel core captures energy from changing magnetic fields. A circuit converts the resulting alternating current into direct current, raises its voltage and stores energy in three capacitors. The researchers say the harvester replenishes energy faster than their custom nanowatt sensor consumes it. The demonstration required sufficiently strong fields near wiring and initially charged capacitors. It did not establish that the system can start from a completely discharged state, and its output cannot power standard electronics.