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--------------------------------- 2623 - NANOTUBE - how to build a radio?
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- When I was a kid, about Noah’s age of 12, I built my first radio. I think it was a Boy Scout merit badge. I used an oatmeal box, salvaged the copper wire from an old solenoid, and wrapped a coil of wire around the box. Sanded off the insulation in a strip. Then, slid a leaf spring along the coils to tune the radio.
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- What an amazing experience to actually listen to a radio signal on my own Crystal Radio.
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- A whole new radio has been invented using nanotechnology. The radio is so small it cannot be seen without the aid of a microscope. The radio is a single carbon nanotube that is much smaller than a wavelength of light. The nanotube is a few nanometers in diameter and 10 to 100 nanometers in length. The wavelength of red light is 700 nanometers and the wavelength of blue light is 400 nanometers.
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--------------------------To get you acquainted with nanometers:
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---------------------------- Your height -------- 1,000,000,000 nanometers
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---------------------------- A computer chip ------- 1,000,000 nanometers
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---------------------------- A Blood cell ---------------- 30,000 nanometers
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---------------------------- Yellow light ------------------- 600 nanometers
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---------------------------- A carbon nanotube ------------- 10 nanometers
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---------------------------- A molecule ----------------------- 1 nanometers
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---------------------------- Space between atoms ----------- 0.2 nanometers
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- To build this radio a single carbon nanotube is mounted to an electrode which is in close proximity to a second electrode and both are connected to a DC voltage source, such as a battery or a solar cell. The DC voltage bias creates a negative electrical charge on the tip of the nanotube.
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- That electric charge is concentrated and is very sensitive to any oscillating electromagnetic fields passing by, such as a radio signal. The nanotube and the electrodes are mounted inside a vacuum tube. The nanotube is so small it easily flexes as the electric forces pass by its electrified tip.
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- The nanotube is especially deflected at its particular flexing resonance frequency. When the mechanical resonance of the nanotube ,like a tuning fork, matches the radio frequency the nanotube vibrates in step with the modulation in the radio signal.
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- With AM modulation the vibrations have greater amplitude in step with the amplitude of the signal. With FM modulation the changing frequency detunes from the center resonance frequency and the vibrations again are amplitude modulated in step with the frequency modulated signal. In this way the radio operation is mechanical and the nanotube is acting as both the antenna and the tuner for the radio.
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- The electrified tip is vibrating in the electric field of the DC bias voltage. This in turn produces a field emission current in the DC supply current. Since this current is in an external power source it can easily be amplified and used to drive a loud speaker.
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- Go on the internet to hear the recording of the first music signals detected by the nanotube radio. This is raw detection without any filtering or static reduction circuitry normally found in amplifiers and radios. So, it sound much like the music I was hearing in my Crystal Radio.
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------------ http://socrates.berkeley.edu/~argon/nanoradio/media/nanoradio-layla.wav
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- The nanometer used in the Berkeley Material Science Division experiment was 500 nanometers long, 5 nanometers wide, an electric charge of 100,000,000 volts per meter, or 3*10^-17 coulombs of charge on the tip. That is equivalent to about 200 unbalanced electrons at the tip.
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- This nanotube radio could be tuned over the 10 to 400 MHz frequency range for reception of radio broadcasts, cell phones, GPS broadcasts, and wireless computer networks. As noted it detects both AM and FM signals.
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- The radio can be course tuned by changing the length of the nanotube. It can be fine tuned by changing the electrostatic field from the DC bias voltage. The fine tuning is like changing the tension on a guitar string to change the frequency of vibration.
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- The radio’s sensitivity can be enhanced by operating at reduced temperatures, by using lower resonance frequencies, by attaching an external antenna, or by using multiple nanotubes all tuned to the same frequency.
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- This invention of a new type of radio will allow production of radios so small they can be implanted inside a living cell. Imagine this nanotube radio receiving brain signals, or muscle functions, or floating through the blood stream. Imagine a radio implanted inside the inner ear that could correct the hearing loss for the deaf.
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- Carbon nanotubes are a series of hollow tubular carbon molecules chained together. The carbon molecule is the strongest molecule known to science. It is literally thousands of times stronger than steel. A carbon pyramid building could be constructed that was 1 mile high.
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- A carbon cable could be connected between ground and an orbiting space station to be used as an elevator cable to shuttle people and supplies back and forth from outer space. Yet, as small as it is it can be used as a sensitive force indicator, electronic sensor, a diode, or even in an electric motor.
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------------------------------------------- See Reviews:
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- 2621 - Nanotechnology Today.
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- 2622 - Nanowire Solar Cells
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- February 16, 2020 851 2623
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--------------------- Sunday, February 16, 2020 --------------------
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