This is a most excellent place for technology news and articles.
In no way is this a discovery.
This is what crystal diode radios are from the '40s.
Some guy built one in Japan, it's basically just a thousand transceivers in a box hooked up to a USB port harvesting radio/wifi signals.
Here's a guy using them to make light:
It's super cool, but not a discovery.
A friend of mine was working on a car chassis and that thing suddenly started to receive radio. You could faintly hear it coming from the chassis and not from somewhere else. We thought we were going crazy. Touching the chassis made it go away.
When I was a kid, I got a stereo system for my birthday one year alongside two big speakers. The speakers, if they stayed powered while the stereo was off, would receive faint traces of radio signal. So round midnight when the house is quiet I could always hear faint voices, just barely loud enough to hear, but quiet enough to make you wonder if you're really hearing it. Nearly scared the dick off me, I thought my parents gave me a haunted stereo. No, turns out it was just haunted by the ghosts of local AM radio.
Haha, that's so cool.
This would be neat for a bunch of passive IoT buttons. No need for a piezo to generate power, good for a couple presses at a time, just simple stuff like that.
Charge up a capacitor and allow a single button press to send a radio signal. Or maybe have enough power to send a WiFi signal.
You're right, that would be the preferred application atm.
I remember making a crystal diode radio with my dad as a kid. You can still buy kits for those.
From Radio Shack?!
Definitely not new. This is how RFID tags work. They harvest energy from the transmitter to power the circuitry in the tag to send back a response.
Not new indeed. Kinda reminds me of old Nextel phones that you would put a little LED on the antenna and it would blink from the EMI when sending and receiving data.
Tap-to-pay on credit card chips, too.
https://en.m.wikipedia.org/wiki/Rectenna
What they've done here is use the very old existing rectenna technology and new types of nanoscale rectenna arrays to capture very low energy radio waves without an external antenna. We're taking -20 dBm or 10 μW.
In the end, I welcome any rectenna advances because if we ever build an efficient optical rectenna it'll blow photovoltaics out of the water by efficiency. Optical rectennas are like fusion power in just how revolutionary they would be to our energy economy.
Dang that's actually a super interesting concept. Thanks for the wikipedia link!
Once its implementation is feasible and it can extract the waste energy efficiently, this innovation will enable new types of devices and uses that will be critical for commercial, scientific, medical and personal.
Sounds like it's still more theoretical than realized, at this point. Still, I can't help thinking this would be really cool for something like a watch or hearing aids.
It's realized, just not scaled.
I was a little careless with how I phrased that. They said in the article they've done it, but it's not "realized" in the sense that it's not to a level of practicality that they'd want it to be. It can currently harvest signals to -20dBm, but they think they can get that to -62dBm for greater efficiency.
The main hurdle, according to them, is there's no schottky diode that fits their needs, and they'll have to engineer a new variant (at the nano scale...?). So, still a theoretical possibility on a more practical level, but this is hopeful news nonetheless.
I agree, it's still very hopeful news that this type of research is being conducted at all, I'm still looking forward to transceivers being built into cell phone batteries and slowly trickle charging constantly.
It will be used for ads...as usual...
it's called an antenna. That's its job.
Tale as old as time. And guess what will happen? Wifi signal strength will go down.
This sort of thing is already being done with many commercial devices. See www.powercastco.com for one of the companies.
This ain't free at all it's more like stealing electricity with extra steps. Though if it does not degrade wifi or radio signal I'm up for it be used aside from just wasting away.
No radio expert here, but would'nt this at some point interfere with the transmissions if deployed at a large scale?
Wouldn't this just decrease the reception for rf devices? Isn't it just stealing power from the system to power other devices?
No more than any random objects.
Think of it like a solar panel. Yes, it blocks light from things behind it, but it doesn't suck light from nearby.
I would find this super cool if it wasnt for the fact that all of the radio frequencies are owned by the military and corporations. Outdoor IoT could be amazing, but it is kind of dead because you cant actually connect it to the internet without laying down cable or using 4G which is horrible for low power applications.
I don't know what kind of idea you are getting. Radio and wi-ifi are waves. The wave is what can be used, you don't care who generated it. To say it somehow the wave is in the air and you just take advantage of it being there to convert it to energy. Doesn't matter what the wave could have been read as. In general a radio station is not going to stop working for a whole region just to stop you from using it.
This is the same take as people thinking wind energy steals wind, or solar energy reduces the sun's efficacy.
Wind energy does.
It's just that we can't extract sufficient energy from it to have any meaningful impact.
Technically, a properly tuned receiver that's using the signal for power can create radio "shadows" behind the device. People have also been caught with giant coils in their attic siphoning power from nearby radio stations and high voltage power lines, because they can detect the power draw.
