Irvine (CA) - Electrical engineers at the University of California Irvine have developed a 1.5 volt biased carbon nanotube receiver which can convert AM radio waves into sound.  The system looks like a laboratory experiment right now, but demonstrates the EM signal detection capabilities of carbon nanotubes in a very straight-forward way.

Researchers began with the basic component of any modern music system, an iPod.  They then ran its output through a device which took the modulated audio signal and converted it to AM radio waves at 1 GHz.  The signal was broadcast through the air to a receiving device which contained a carbon nanotube detector, a 1.5 volt battery, an amplifier and speaker.  Overall, the signal demonstrated traveled just a few feet, but it was demonstrated that it could be blocked by placing an aluminum plate between the transmitter and the receiver.  In addition, when the 1.5 volt battery was remove the carbon nanotube was no longer biased and the sound quality dropped to almost static and white noise.  Inserting the battery brought back the sound.

The basic radio components are 1) Transmitter, 2) iPod, 3) transmit antenna, 4) receive antenna, 5) bias plus carbon nanotube modulator, 6) battery, 7) preamplifier and 8) speakers.

The carbon nanotubes were grown in the lab.  They then had palladium electrodes grafted onto them through optical lithography.  The device was constructed and tested using relatively straight-forward radio components.  The team performing the work consisted of only two researchers, associate professor Peter J. Burke and Chris Rutherglen.

The practical applications of a carbon nanotube based receiver are not found easily in AM radio transmissions, which rely on a constant frequency and variable signal amplitude for conveyance.  The true potential lies in more complex systems, such as tunable frequency applications.  Now that it's been shown that a carbon nanotube can attenuate radio waves accurately, the possibility exists of increasing the frequency and moving from AM signals to FM and PCM (Pulse Code Modulation).  These kinds of signals are used typically with wireless devices, including cell phones and WiFi.

Carbon nanotubes are proving to be very capable in a wide array of disciplines.  It would not surprise TG Daily to learn that this foundational component wiles its way into many devices of the future.  So far the carbon nanotubes have been shown to be excellent conductors of heat, both conductors and insulators of electricity with proper doping or other structures added, and now electrical modulation.

What a wonder-drug

Oct 25, 2007 12:32     

It's like the penicillin of the tech world! Good stuff! Next thing up, figure out how to use it for fuel cells and break that free-energy barrier!
Jay report abuse vote down vote up Votes: +0

nice powersource...

Oct 25, 2007 13:30     

good news for nano-power generation plants. Use radio waves to feed the power to the nano-generator, then use acoustic waves to power the rest. Isn't 1GHz a little too high for AM?
dennis report abuse vote down vote up Votes: +0

Wow! They invented the Crystal Radio

Oct 25, 2007 15:14     

Many substances can demodulate AM radio. This technology is a hundred years old.
J Doe report abuse vote down vote up Votes: +0

I saw this on Gilligan's island

Oct 25, 2007 15:24     

There was an episode where Gilligan was receiving radio stations in his mouth. His dental fillings were demodulating the radio waves.
anon report abuse vote down vote up Votes: +0

AM

Oct 25, 2007 15:27     

You can us AM on any frequency. while its not realy in the range of your home sterio the process is the same no matter what frequency you use. This just may have been a concept for the frequency range they where testing.
anon report abuse vote down vote up Votes: +0

How can it be a 100 years old??

Oct 25, 2007 16:49     

J Doe - You propose that this technology is around 100 years old. Please elaborate more, as that carbon nanotubes were created in the 1900s but we know that the discovery of these tubes wasnt till 1990s. AM is used on wide range of frequencies not just the AM Radio frequencies assigned by the FCC. AM is the modification of the amplification waves to send audio signal
Brad report abuse vote down vote up Votes: +0

miniturization yah

Oct 25, 2007 18:18     

Soon we can have that AM radio implant in your ear. I guess anything that gets basic components smaller will result in cheaper and better energy consumption. Its good that they are starting to make practical components from these materials. Soon we can have an Intel P10 the size of an Ipod nano that connects to your TV with WIFI or to monitor contact lenses with your virtual mouse and keyboard controlled by brain waves hehe, extra brain ram please.

Jason report abuse vote down vote up Votes: +0

carbon nanotubes

Oct 25, 2007 19:15     

I think carbon nanotubes are cool but at $100-$300 a gram going to be a while. Oh and palladium is more expensive than platinum. That is one expensive ass radio.
Ben report abuse vote down vote up Votes: +0

Ben, $300 buys you, what, 8.4x10^20 buckyballs?

Oct 25, 2007 20:33     

For $300, everyone on the planet gets 100 billion of them. Sounds pretty cheap to me... yeah... I know... the nanotubes have many times more atoms than the buckyballs. But it still just doesn't sound that expensive. I wonder what the signal bandwidth is on these?
TeraMedia report abuse vote down vote up Votes: +0

We did this ten years ago

Nov 05, 2007 20:29     

I am glad to see interest in this area which we first pioneered over ten years ago, and have 7 patents issued to date. More details at http://www.ambitcorp.com
Bob Crowley report abuse vote down vote up Votes: +0

Gilligan and Laurie Partridge

Dec 17, 2007 18:59     

I do not recall an episode where Gilligan picked up radio signals, but I do remember Laurie Partridge picking up the Rolling Stones on her braces.
Mike report abuse vote down vote up Votes: +0