Full disclosure: I work for an audio beacon startup (in bio).<p>It&#x27;s great to see this article getting attention.  I also shared it two days ago in a comment on a story about audio beacons (<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10563134" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10563134</a>).<p>Mainly my goal was to remind people there are some realistic use cases where audio beacons &gt;&gt; BLE beacons.  For some reason audio beacons seem to be often forgotten about as a viable alternative.