Don't have Telegram yet? Try it now!
https://hanzama.x0.to/2020/06/19/9m-to-the-first-smartphone-with-ultrasound-and-voice-input-itmedia-news/
9m先のスマートフォンを超音波で“攻撃” 人に聞かれずに音声入力も(ITmedia NEWS)