this post was submitted on 05 Dec 2023
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Researcher has developed, at a cost of less than one dollar, a wireless light switch that runs without batteries, can be installed anywhere on a wall and could reduce the cost of wiring a house by ...::A U of A engineering researcher has developed a wireless light switch that could reduce the cost of wiring a house by as much as 50 per cent.

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[–] FlyingSquid@lemmy.world 10 points 2 years ago (4 children)

What makes his system unique is that the switches run without batteries, harvesting energy from ambient sources such as radio frequency signals.

That is mind-blowing.

[–] DreadPotato@sopuli.xyz 12 points 2 years ago (1 children)

Last time i saw a product claiming to run on energy harvested from radio-waves, it was a kickstarter project that (surprise surprise) turned out to be a complete scam.

[–] luthis@lemmy.nz 5 points 2 years ago (1 children)

It is totally possible to harvest energy from radio waves, it's just such a tiny amount that you could barely light a LED

[–] DreadPotato@sopuli.xyz 1 points 2 years ago* (last edited 2 years ago) (1 children)

Yeah that's my point, the energy you can actually harvest is ridiculously small. Even if it was slowly charging a capacitor with this harvested power and saving it for later use, how often can i use the switch before depleting the energy faster than it charges? "oh sorry, you'll have to wait 5min to turn on your lights again, It's not quite charged enough"

[–] luthis@lemmy.nz 1 points 2 years ago

My guess is you would get a couple seconds of light before needing several hours to charge it up again.

[–] dgriffith@aussie.zone 3 points 2 years ago* (last edited 2 years ago)

I have a Philips Hue wireless switch that has no batteries. The click action when you press the button is enough to drive the transmitter. The button moves in about 4-5mm when pressed and that is all that's needed to drive the transmitter.

What's really mind-blowing is that such trivial amounts of energy runs a transmitter that sends a specially coded pulse (not even just an on off pulse of RF) thirty feet to the receiver.

[–] BrianTheeBiscuiteer@lemmy.world 3 points 2 years ago

I've heard of this before but I think it's really a trickle charge. Not practical for charging a phone or anything like that.