Ubicomp paper presents batteryless, electronics-free ultrasound tags that attach to household objects and are identified by a wearable microphone via unique acoustic signatures.
Key Takeaways
Tags are passive mechanical structures (no power, no circuitry) placed on doors, faucets, cabinets; movement causes unique ultrasonic emissions above 20 kHz.
A wearable device bandpass-filters 20-100 kHz input, extracts spectral peaks across three frequency bins, and classifies tags using a tolerance-based matching algorithm.
Physics-based geometric modeling generates thousands of distinguishable tag designs; open-source pipeline includes fabrication guide and Home Assistant integration.
Classification requires 40% of labeled frequencies matched within ±400 Hz and a penalty score below 0.2, providing robustness to environmental noise.
Targets elder care, smart home automation, and building instrumentation without cameras or microphones capturing private content.
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