"Wireless" transmission of sounds through the air to achieve some programmatic purpose is relatively widespread, although not very well-known. The air is a noisy medium, so ultrasound is often used to move the sounds squarely out of the frequency range that humans can produce or hear, but usually keeping it within ranges that off-the-shelf microphones can record and speakers can produce.
In recent years, one particularly significant contributor is Boris Smus [1] who released some example code in 2013 and went on to develop the Google Chromecast's ultrasonic pairing mode [2].
Ultrasonic networking has also been leveraged by tracking apps and SDKs [3], and has occasionally featured as a product pitch [4]. It also pops up every once in a while as a proof-of-concept, Show HN, or github code dump -- it's one of those "I can't believe this isn't done more often, so I'm gonna do it" ideas whose deployment is actually more widespread that most people suspect.
In recent years, one particularly significant contributor is Boris Smus [1] who released some example code in 2013 and went on to develop the Google Chromecast's ultrasonic pairing mode [2].
Ultrasonic networking has also been leveraged by tracking apps and SDKs [3], and has occasionally featured as a product pitch [4]. It also pops up every once in a while as a proof-of-concept, Show HN, or github code dump -- it's one of those "I can't believe this isn't done more often, so I'm gonna do it" ideas whose deployment is actually more widespread that most people suspect.
[1] http://smus.com/ultrasonic-networking/ [2] https://gigaom.com/2014/06/26/chromecast-will-use-ultrasonic... [3] https://news.ycombinator.com/item?id=13337949 [4] https://www.chirp.io/