US team builds graphene sensor that runs 24 hours without a battery

Researchers at the University of Arkansas and University of Michigan have built a graphene device that harvests energy from magnetic fields around household wiring to power an ultra-low-power temperature sensor. Stored charge keeps it running for at least 24 hours during a power outage, and potentially up to a week.

• A graphene inductor harvests energy from magnetic fields around power lines
• The sensor draws nanowatts and can run unattended for years
• Stored energy lasts at least 24 hours without power, up to a week
• Next step is combining light, heat, sound and motion harvesting