Not fully related, but early TV remotes used sound rather than IR. The buttons made a distinctive “click” noise, from a mechanical mechanism. The different clicks were detected in the TV and used as input.
Plus side, no batteries to deal with.
Down side, about as (un)reliable as you would expect.
…when have remote signals ever used microphones?
Not fully related, but early TV remotes used sound rather than IR. The buttons made a distinctive “click” noise, from a mechanical mechanism. The different clicks were detected in the TV and used as input.
Plus side, no batteries to deal with.
Down side, about as (un)reliable as you would expect.
That’s wild. How did the TVs identify the distinctive sound? That seems like it would be a pretty interesting engineering trick.
I believe it was old school analogue electronics, but I’m speculating there.
I just looked it up, it was ultrasonic signals. The main one was the Zenith Space Command.