It&#x27;s a unique idea that I could see being useful in select situations. The reliance on wearable microphones sounds like a downside.<p>Also I guess this might be annoying for pets that can hear well beyond 20 kHz.

Unlikely because it’s ultrasonic sound, at least if you have brick walls.<p>Could work for drywalls

If you are constantly looking at your smartphone and ignore the real world ... yes ;-)

Do you need a signal that tells you the window is open if you are in the same room?

The microphone is on a smart watch the user is wearing.

Im not sure I got it. It generates acoustic signals and a microphone server picks them up.<p>If so, will it penetrate through walls?

Trivia time! The first practical wireless remote control for TVs also used ultrasound: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=MLPk1Us62xQ" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=MLPk1Us62xQ</a>