Batteries Not Included, or Required, for These Smart Home Sensors

3 days ago

Georgia Tech researchers developed small, battery-free metal tags that use unique ultrasonic fingerprints to detect movements such as door openings, gym reps, and bathroom use. The tags cost only a few cents each and are smaller than a penny.
The tags are mounted on surfaces like cabinets, with a tab attached to moving parts. When opened, the tab strikes the metal disk, generating an ultrasonic pulse detectable by wearable devices. The tag's shape determines its frequency, allowing unique identification for activity recognition.
Applications include monitoring water use, assisting elderly care, counting gym exercises, and tracking items in archiving or waste management systems. The tags operate in the ultrasonic range (above 20 kHz), making them silent to humans and private due to limited sound travel.
Researchers created a simulation tool to design metal disks that produce specific ultrasonic frequencies, with potential for thousands of unique tags. The system uses simple algorithms instead of complex machine learning, reducing computational power requirements.
The project is a collaboration between engineering and computing researchers, supported by funding from the National Science Foundation and other organizations. A viral Instagram video generated widespread interest, with suggestions for diverse applications.

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