4 ms·
The basic thought here is that there's a ton of energy in our environment, specifically in the form of high-amplitude RF waves from TV broadcasts, and we should
by willscott 13y ago
The basic thought here is that there's a ton of energy in our environment, specifically in the form of high-amplitude RF waves from TV broadcasts, and we should be able to use that energy to do work.
This project is trying to figure out what the equivalent of an rfid tag looks like with that power model. They come up with a scheme of being able to absorb versus reflect the ambient signal to communicate between unpowered tags. Maybe the most productive way to think about this is as a step into the larger research area of how to effectively harvest energy and do useful stuff with devices that don't need batteries.
- femto 13y agoWhen I was at university, there was a final year undergraduate project that used similar technology. In this case, the student was trying to build a passive radar jammer, which modulated the reflected radar signal in a way that the driver of a car could select what speed they wanted to appear on a traffic radar. The method was to build a corner reflector out of three orthogonal conducting sheets, but to connect one of the sheets to ground via a PIN diode switch. By turning the diode on and off, the reflection coefficient of the corner reflector could be modulated, in turn modulating the reflected signal.
- jevinskie 13y agoDo you have a link? That is fascinating! Did it end up working?
- femto 13y agoI don't have a link. It got written up as an undergraduate thesis in about 1991, but as far as I know the University of Sydney doesn't keep copies of such documents. I'm not sure what the outcome was, though it must have gotten to a certain point of success, since I've memories of a car driving around with a corner reflector on it. The same student was experimenting with using a plasma as the modulated reflector, but that one ended when he connected the wrong end of the vacuum pump to his gear, accidentally pressurised it, and blew it up!
- StandardFuture 13y agoSo it's not really some new uber-complex 'recycled communications network' as much as it is purely "Radio Solar Powered" ...
- waster 13y agoToo bad Nikolai Tesla's not around to help us figure out how to harness that energy.
- NicksTCoil 13y agoHis coil works in reverse too. ;-)
- EEGuy 13y agoThere isn't much useful "work" one can do with a microwatt at "human" scale in a day. Except, as this paper shows, build a networkable wireless system camping on those microwatts. Not meaning to be critical, rather just want to clarify that our modern-day gigawatt-scale energy grid yields an enormous 15 orders of magnitude more electrical power than the microwatt-scale "harvesting" of TV signals can. That's an enormous power spectrum, shown to have a newly useful application (batteryless mesh networking) at microwatt scale.