this post was submitted on 18 Aug 2023
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Serious question from a beginner in electronics. For reasons I do not fully understand, I have become fixated on the idea of collecting small amounts of electricity from “interesting” sources. I don’t mean “free energy”, instead, I mean things like extracting a few mV from being so close to a AM radio tower using two tuned loop antennas in phase with each other, or getting a few mV from the rain’s kinetic energy with PTFE and using two electrodes which are shorted when a drop of rain hits it. In short, I’ve done small experiments to confirm that I can get a few mV and enough to get me excited but not much more. I know I’m not going to get much power out of this, but I’ve been able to charge a NiMH battery a few mV by being a quarter mile from an AM radio station with my antenna setup. It would be fascinating to me if I could store these small charges in something like a 5V USB power brick eventually.

The smarter idea would be for me to harvest energy with the sun or from the wind or a stream. I’m tinkering with this as well, but larger amounts of electricity scare me for right now. I guess I’ve seen enough experimental sources of harvesting electricity and I’ve gotten the itch to invent, which is a dangerous itch for a newbie like me to have.

The best advice I’ve seen online (ok, it was ChatGPT) is that it’s just not worth it to work with such small amounts of electricity, because the equipment required is too expensive and sophisticated (e.g, devices to read the charge of a capacitor without discharging it) to make anything that’s efficient enough to be worthwhile. Would you agree? Do you know of some other fascinating source of gathering electricity that I should also waste lots of time on?

I just have all these electronic components and magnets and when I move them together the numbers on multimeter get bigger. it’s neat.

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[–] [email protected] 3 points 1 year ago (1 children)

Yeah, exactly. This isn't how radio signals work at all. This is a tall tale and never happened. When I searched for such a story, none came up. When I removed the location and searched for the same type of story, thousands of them are floating around the internet. Powering military tents from radar emissions, powering homes from radio tower emissions, all of them are re-tellings of stories someone once heard from the 1930s, 1940s, and so on. They're effectively chain letters for the confused.

[–] [email protected] 2 points 1 year ago

I've heard teachers telling the same story, but so it happened locally in a different country entirely. Sounds like a scare legend.