Voice-activated recording on Shabbat and Yom Tov

Hi,

Speaking, and thereby activating a voice-activated recorder, is prohibited on Shabbat and Yom Tov, even where one does not intend to activate the recorder, where that is a guaranteed result of one's speech.

(Rav Moshe Feinstein, Igrot Moshe Yoreh Deah 1:173)

Have a great day,
Mordechai