"By pressing a button on the remote, you set off a spring-loaded hammer that strikes a solid aluminum rod in the device, which then rings out at an ultrasonic frequency. "
And that's where the term "clicker" came from, as opposed to the more modern "remote".
I had a TV with an ultrasonic remote. It was a nightmare. Whenever I moved the curtains, random things happened with the TV, including the volume hitting a 10 in the middle of the night...
maybe still better than the flashlight/photocell types!
I had one of these TVs when I was a kid, it came from my grandparents' house when they got a new one. We also had a dog that wore a steel-linked choker collar, and the TV channels would change, or the TV would turn on an off when he ran around and jangled the collar.
this is a space for Cassette Futurism -- retro images, media, design and technology from the 70s and 80s
*reposts to get started, mods welcome