Autonomous (without batteries) wireless temperature sensor, door opening, etc. Which ones exist, how do they work?

Question

Smart House

Hello!
Interested in sensors on the principle of "attach and forget", capable of independently extracting energy from heat, light, radio waves, etc. for wireless transmission of measured parameters, incl. for alarms or "Smart Home" systems, strain gauges.
What exist, on what technologies, what are the prospects?

Answer 1

Look here www.arroweurope.com/markets-solutions/solutions/the-drop.html

Answer 2

It's probably easiest for you to use a battery + solar battery. the rest just seems expensive to me

Answer 3

well, I haven’t seen anything like this yet, there are just more ergonomic sensors, like the Ajax security alarm system . So it turns out a sensor on batteries, but they keep the norms. Well, they even work when, but they work often at work, then enough is enough. In any case, sensors with batteries will also have to be charged.