"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. "
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.
And that’s where the term “clicker” came from, as opposed to the more modern “remote”.