A Near-Ultrasound (NUS) Data Link
canopic jug writes:
Bunnie Huang has published a reference design for a near-ultrasound data link.
We were requested to investigate near ultrasound" (NUS) links as part of our research on developing the Simmel reference design for a privacy-preserving COVID-19 contact tracing device. After a month of poking at it, the TL;DR is that, as suspected, the physics of NUS is not conducive to reliable contact tracing. While BLE has the problem that you have too many false positive contacts, NUS has the problem of too many false negatives: pockets, purses, and your own body can effectively block the signal.
That being said, we did develop a pretty decent-performing NUS data link, so we've packed up what we did into an open source reference design that you can clone and use in your own projects.
Previously:
(2020) Your Apps Can Pick Up Ultrasonic Signals You Can't Hear
(2017) Ultrasound Tracking Could be Used to Deanonymize Tor Users
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