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.
It sort of explains it, if you already know how RF charging works. It’s still pretty new tech, but has been around for a bit.
“RF wireless charging is a type of uncoupled wireless charging in which an antenna embedded in an electronic device can pick up low level radio frequency waves from external sources and convert the waves’ energy to direct current (DC) voltage.”
So knowing that and the article referencing about wireless light switches already being a thing, but being battery powered, it seems that it’s a standard wireless light switch that has just been modified with an rf wireless charging receiver that will charge a small battery or some capacitors to run the light switch.
IMO, until you’re using rf to power more than just light switches, you’re wasting a lot more electricity than it’s worth, compared to changing out batteries in your light switches once every like 5 years. If RF gets standardized completely and it starts helping to power a whole mess of things like your smart watches, phones, air tags, clocks, etc then it will be pretty sweet.
Didn’t the soviet union have radio bugs that worked like that? No power of their own and hard to detect but if you blast them with RF they can use some of that energy to turn into small very weak signal transmitters. One of the culprits of ‘Havana sickness’ if I remember.
Found the sauce
https://en.m.wikipedia.org/wiki/The_Thing_(listening_device)
“RF wireless charging is a type of uncoupled wireless charging in which an antenna embedded in an electronic device can pick up low level radio frequency waves from external sources and convert the waves’ energy to direct current (DC) voltage.”
I can’t find that quote in the article—or anything that definitively indicates they’re talking about RF power rather than RFID signals (other than saying the transmitters “power up” all the switches, which could just be sloppy terminology.)
The article says they are powering it using dedicated transmitters:
“each floor would have one or two RF (radio frequency) power transmitters to power up all switches inside the house.”
It’s confusing because earlier they talk about energy harvesting, which implies “free”. But then they talk about how you will need to run these transmitters, which certainly isn’t free.
Isn’t this ambient RF that’s there anyway, like your WiFi network and stuff like that? I don’t see any harm in harnessing it for low power applications like those switches, sensors, etc.
No. They need a separate rf field generator. Not just picking up on any stray rf or rf from your wifi. It says as much in the article.
As to the technical reasons behind why your routers frequency can’t be used, I don’t know. I’m guessing the 2.4 and 5ghz range just isn’t something that works at a proper enough frequency to oscillate and gather charge. They’ve been using a lower frequency of around 915 mhz for rf chargers.
