It used to be possible to make a radio receiver out of a diaper pin and a blue razor blade. The coating on the blade acted like a crystal. You needed a cheap pair of headphones or a tiny transistor radio speaker. I made one when I was a kid, and I could clearly pick up 77 ABC in New York City from 50 miles away.
Razor blades aren't blue anymore, but there must be other things that work.
The other day I learned that the National Ignition Facility uses actual cat whiskers.<p><a href="https://www.cbsnews.com/news/nuclear-fusion-60-minutes-2023-01-15/" rel="nofollow noreferrer">https://www.cbsnews.com/news/nuclear-fusion-60-minutes-2023-...</a><p>> Michael Stadermann: All the components are brought together under the microscope itself. And then the assembler uses electromechanical stages to put the parts where they're supposed to go-- move them together, and then we apply glue using a hair.<p>> Scott Pelley: A hair?<p>> Michael Stadermann: Yeah. Usually something like an eyelash or is similar, or a cat whisker.<p>> Scott Pelley: You apply glue with a cat whisker?<p>> Michael Stadermann: That's right.
> They regained prominence in World War II because of their ability to operate at microwave frequencies<p>I'd always understood the WWII relationship with cats whiskers to be due to PoWs making radios from materials that they had access to.<p>Edit: some evidence to suggest my understanding wasn't wrong, if not complete:
<a href="https://www.bbc.co.uk/ahistoryoftheworld/objects/C5q84AOFTtq8T20c1X5IzQ" rel="nofollow noreferrer">https://www.bbc.co.uk/ahistoryoftheworld/objects/C5q84AOFTtq...</a>
They also had memristive properties:
<a href="https://ieeexplore.ieee.org/document/6518277" rel="nofollow noreferrer">https://ieeexplore.ieee.org/document/6518277</a>