cross-posted from: https://lemmy.ml/post/18426215
Tale as old as time. And guess what will happen? Wifi signal strength will go down.
Any receiving antenna is basically an energy harvesting device. Usually, it is specially designed to harvest just enough energy to actually receive the signal in order not to weaken the field. In the 2.4GHz spectrum, where WiFi and BT are at home, a sender is limited to 10mW of power. The more power energy harvesting devices draw from this field, the less will be available for other devices to actually receive the information.
Technically, an electromagnetic field of a frequency f will induce an alternating current in an antenna of length lambda/2 (or lambda/4 or even lambda/8, with less power received the smaller they get and lambda=wavelength=speed of light/frequency) that the receiver can “take out” at the antennas mid point and feed it into an amplification circuit.
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.
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.
Maybe i left out too much context.
Im not talking about the research itself, but about how it could be utilized.
Their idea (having small devices that can be powered by nothing but stray radiowaves) apparently works and is great by itself.
However its usefullness is limited if you cant somehow connect those devices with the rest of the world. Thats the issue im complaining about.
There are tons of small devices that don’t have to be connected to be useful. Lots of personal items or small sensors.
This is the same take as people thinking wind energy steals wind, or solar energy reduces the sun’s efficacy.
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.
Wind energy does.
It’s just that we can’t extract sufficient energy from it to have any meaningful impact.
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.
That’s interesting! I thought that if you for example have a 50w RF transmitter, taking 40w from it would make it act as a 10w one for the other devices around it.
Thx for the explanation :3
It you could build a 40w antenna sure, but it’d basically have to be a dome surrounding the transmitting one at that point.
The dawn of the Matrix is almost here chunmers!
