Sciencemadness Discussion Board

How would I go about building a simple circuit that...

The Fountain of Discordia - 26-5-2009 at 21:29

Hi, me and a friend are interested in the idea of Brainwave Entrainment, but not in the weaker, light and sound based forums of it. Therefore, we wanted to build a magnetic helmet. Now, before going "Oh god, another newage fool." Just know that this type of device is used in clinical serttings to help treat suicidal depression and other conditions, to great sucess. So, the basic problem is I'm not quite sure how to build a circuit that would let me modulate the frequency of the magnetic pulses. Would anybody be willing to help me out?

woelen - 26-5-2009 at 22:55

You can use a voltage controlled oscillator for modulating the frequency of the signal. Simply apply a variable voltage on one of the pins of this circuit and you have your variable frequency signal.

http://www.alldatasheet.com/datasheet-pdf/pdf/8985/NSC/LM566...

This is a single integrated circuit, you need to provide things like power supply and of course you also need to supply an external voltage, which does the modulation.

The output of this little chip must of course be amplified, such that it can drive an electromagnet for generating a magnetic field.

From a non-technical view: Are you attempting to do this on yourself or your friend? Making a variable magnetic field can be a fun project on its own, but experimenting with this on your own body does not seem like a wise thing to me. But that's just my opinion, it is your body and your responsibility.

not_important - 27-5-2009 at 04:27

That application requires fairly good control of frequency, 0,1 Hz as a minimum for frequencies in the 3 to 20 Hz range, several experiments reported values to 1/100 Hz. A simple oscillator may not be precise, accurate, or stable enough to be useful.

The waveform can be important, most studies used sine waves. Pulses or square waves are going to produce harmonics all over the place, from some reports a rather undesirable condition.

Control of field strength is also needed, I assume you have means to measure it? Or maybe not seeing as you are asking about a rather basic technique.

I'd go for direct digital synthesis with the result driving a 8 to 12 bit DAC, or mixing two sine waves in the audio range and low pass filtering the result.

Actually applying such fields to a subject means having good control of the signals, not using some cobbled together kludge of dubious quality. Stick to the audio based forms until you've learned enough electronics that you don't need to ask how to build such devices.

chemrox - 27-5-2009 at 21:15

I've heard rumors of such devices being used to treat addictions eliminating abstinence syndromes for tobacco, alcohol and heroin. I cannot find any papers and am reminded of the inventor that discovers a pellet made of cheap common ingredients that when added to water makes a fuel that competes with gasoline. The story goes the inventor is killed or retired to the So Pacific...A more modest clinical accomplishment might be more impressive. I'd be interested in reading if you have some refs.

Mr. Wizard - 28-5-2009 at 06:00

I t would also be possible to use the output of a computer's sound card to obtain almost any sound-wave or combination thereof. I'm sure there are free-ware sound generation applications available, and the electronics is sitting in front of you. Even an old 'junk' PC could serve as a source of sound to feed an audio amplifier. The audio amplifier is made to supply current to make electromagnetic pulses. You will have to match the 'impedance' of the coil to the 4, 8, or 16 ohm amplifier.

Vogelzang - 28-5-2009 at 12:53

In the book Psychedelic baby reaches puberty by Peter G. Stafford they discuss the hallucitron, a device that alternately flashes lights on closed eyes to produce various illusions.

http://www.google.com/search?hl=en&client=firefox-a&...

[Edited on 28-5-2009 by Vogelzang]

chemoleo - 28-5-2009 at 17:26

I think this is what he refers to:

http://en.wikipedia.org/wiki/God_helmet

May you find thy spirit with electromagnetic fields!

Vogelzang - 29-5-2009 at 12:31

Maybe it can facilitate out of the body experiences.

hissingnoise - 29-5-2009 at 13:06

Or, failing that---out of the head experiences. . .
People having multiple mini-strokes have reported having being overcome by pleasant feelings of great anticipation just before the onset of a stroke.
This is thought to relate to electrical/magnetic disturbances which appear to be connected to the build-up to strokes.
As for the GodHelmet, it isn't something I'd want anywhere near my remaining quota of brain cells---and I would have credited Dawkins with the intelligence to avoid such contraptions, but perhaps he simply wanted to display total fearlessness. . .
When I feel in need of an expansion of consciousness, a few tokes of cerebral ganja suffices!


[Edited on 29-5-2009 by hissingnoise]

not_important - 29-5-2009 at 16:51

A better Wiki link would have been http://en.wikipedia.org/wiki/Transcranial_magnetic_stimulati...

This is somewhat different than the earlier sinewave stimulation research. TMS uses short pulses of current to drive electromagnets generating fields of 1 to 4 Tesla, using particular patterns that are more easily produced using a computer rather than from simple circuit. The coil shape is somewhat important, as are its electrical characteristics as the pulses have short (~100 usec) rise times.

Indeed, there are commercial products meant to be used with PC sound cards, and coming with the software to produce the desired patterns. One such product, which by no means am I endorsing, is
http://www.shaktitechnology.com/winshakti/rotating/index.htm

Or you could take a different route, as per Sasha
Quote:
My response to him was to ask him three questions. One: Was he familiar with the psychedelic experience? "Yes," he said. Two: Would he trust me as a guide in such an experience? He looked at me strangely for a moment, and then said, "Yes, of course." Three: Would you come down the hall with me to the chemistry lab and trust me if I would try a quick experiment? "Sure," he said. So we went down to the lab where there was a giant dry-ice container, and I opened it up, and asked him to put his head inside this container and to breath twice, deeply, through his mouth. He did this, and I caught him as he stumbled backwards. "Wow," he said. "That was a totally unexpected turn-on." "Did it remind you of LSD?" "Yes," he said. "Initially I went out there quite far, but you were there and I had no problem re-centering myself."

We returned to the office. I asked him, "Do you think you could separate the mechanisms of action of LSD on you, as distinct from the actions of carbon dioxide?" He told me quite honestly, "No, they sure came on in the same way." So, I asked him, could you possibly design a research project that would result in an explanation of the difference of the action of LSD and of carbon dioxide? He shook his head. He admitted that it might be very difficult to explain the action of LSD (which has some 49 atoms in its structure) if he couldn't explain the action of carbon dioxide, which contains only 3 atoms.

hissingnoise - 30-5-2009 at 07:17

Let's all get...er...asphixiated. . .