Good post Karen.
The PIR sensor exploits the Albert Einstein photo-electric effect where IR photons hit the detecting material to generate charge.
Great primer on PIR, Karen!
When I was a kid, I had this science activity book that contained a page that was a Fresnel lens with instructions on using it to cook hot dogs--and a stern warning not to cook…
Solar cookers are fun! I have an old projection tv screen I salvaged that's waiting for spring, when the sun comes out more often here in the midwest. Don't know what I'm gonna "cook", but it's gonna be…
Great introduction. Just the right level of details to pique my interest. I have used them but never really spent any time understanding them.
Be careful, if what you cook splatters, you can get stuff on the lens.
Also be careful with the focus, it does not take a very large focus circle to generate a lot of heat in a small area.
Great if you are making charcoal, not so great if you actually want to eat what you cook.