I was doing a little research in RFID technology, and I was wondering…
According to this they can store up to two kilobytes of information, yet don’t need a power source to transmit it. Apparently the radio signal that the antenna on the chip powers the return signal as well.
I was talking about this to the office crackpot and he was saying that Tesla invented this a hundred years ago.
:dubious:
I know that supposedly he was able to light up florescent light bulbs wirelessly. Was the crackpot even close?
It’s nothing fancy. RF energy is energy. A crystal radio is powered only by the electrical signal that is induced into its antenna by the RF transmission. Strictly speaking, you could rebroadcast this with its own power, and it would be a weak transmission. All you’d need is a sensitive receiver to pick it up.
Well, I don’t quite understand the second sentence here, but the RFID tag is not really “transmitting” as much as it is “reflecting”. As your linked article states, this technology is not really that new - it’s just getting cheap enough to be practical.
Tesla “invented” it in the sense that he helped come up with the framework for early radar technology, which is similar to what’s going on with these RFID tags. It’s like saying the Wright brothers “invented” the 747.
Also, unconnected fluorescent light bulbs will light up in the presence of a large enough electric field; look up “Van de Graaf generators”.
I don’t know if Tesla really invented it, but Tesla was definately aware of the fact that you can transmit energy via radio waves. Tesla had a grand idea for transmitting residential power via radio waves. It would basically be free energy for everyone. All you had to do was stick an antenna up and receive it. Unfortunately, his idea just wasn’t practical.
Do a google search for “tesla radiant energy system” for more details.
Tesla did end up with some patents related to his system, so in that respect one could easily make the claim that he “invented” the system for transmitting energy via radio waves. Your office crackpot was right in this case.
There are several different types of RF tags. Some use diodes, which reflect back energy. The exact combination of RF diodes will determine which frequencies are reflected back, thus encoding a unique binary number into the tag. These types of tags aren’t used much any more, at least not in the US.
The most commonly used type of tags have an integrated circuit in them. They receive an encoded data packet, then transmit out a data packet which includes the unique ID encoded into the tag. These types of tags are not reflecting. They are receiving and transmitting. They come in two types, beam powered and battery powered. The beam powered tags take incoming energy from the RF beam and store it in a capacitor. Once the capacitor is charged, the chip switches on and does its thing. The battery powered ones typically have a much longer range than the beam powered ones, but then you’ve got the battery to deal with, which doesn’t last forever.
EZ-Pass toll systems and many building security ID cards use the beam powered tags. Beam powered and battery powered tags are used on freight systems and cargo containers. RFID chips implanted into pets are beam powered.
Knowing Tesla, he had a half a dozen methods of wireless transmission of electricity, but in the case of the “free electricity” deal, wasn’t it transmitted through the earth? I seem to remember an anecdote WRT to that that involved a number of pissed off horses getting shocks through their horseshoes.
Nope, it was transmitted through the air. If you wanted power, you just put up an antenna with a capacitor attached to it. I don’t recall what mechanism Tesla dreamed up for conditioning the power after it came off of the antenna rig.
I’ve never heard of a system that transmitted power soley through the earth. It’s kinda hard to do, since the earth tends to act as one great big ground sink (that’s why electrical grounds are referred to as “ground” or “earth”). There have been power systems that used the earth as half of their circuit. You run a wire from your generator out to all of your loads, then instead of running return wires all the way back to the generator, you just ground all of the returns. This means you get to use only half as many wires, and if you are a fledgling power company and you have miles and miles and miles of wire to run, cutting your wire cost in half becomes important. These systems had reliability problems, as well as suffering from problems of having the ground conductance in an area change with the seasons. Plus, in some areas, it was just hard to get a good ground connection. It’s pretty easy to see how horses and other animals might get a bit upset if there is a voltage gradient across the ground they are walking on due to poor conductivity.
What tesla invented was a primative system of radio control. He had a continouos wave low-frequency RF transmitter, tuned to one frequncy. He would then key the signal 9turn it on and off). This signal was received by a small electrically powered boat,he had a sensing circuit that responded to the RF signals 9which included a “NAND” gate-the building block of modern computers. tesla called this invention “telautomatics”, and filed patent covering these inventions in 1891! Is was in no way comparable to an RFID system, but incorporated most of the modern elements of RF remote control.
tesla demontrated this to the US Navy (he thought it would be useful for controlling torpedos). the navy expressed no interest.
I heard that many years later, patent lawyers at IBM were preparing patenst of IBM’s digital computers. they stumbled across the tesla teleautomation patenst, and discoverd that tesla had invented the NAND gate some 60 years before.
