Hi Allen
Is there any quantitative way of describing "high" or "low"? Is there also a way of measuring signal strength in some standard units? During the demo i witnessed the host claimed to experience all sorts of feelings while the generator was on. I experienced nothing at all but definitely heard a difference in tonal balance and bass and a slightly different perception of acoustics. To tell the truth i hear more pronounced changes by swapping capacitors and other passive parts but it certainly seems worthwhile to build a clone as it costs practically nothing.
Is there any quantitative way of describing "high" or "low"? Is there also a way of measuring signal strength in some standard units? During the demo i witnessed the host claimed to experience all sorts of feelings while the generator was on. I experienced nothing at all but definitely heard a difference in tonal balance and bass and a slightly different perception of acoustics. To tell the truth i hear more pronounced changes by swapping capacitors and other passive parts but it certainly seems worthwhile to build a clone as it costs practically nothing.
I've learned to never argue with a wife hearing things from the next room. I wouldn't argue about this any sooner than I would argue about creation science.
No I cannot explain how Allen's suggested two coil transformer works as a radiating antenna. I am simply taking his word that it does work. If I want to build one of these things then I need at least a suggested working model to follow. Such units are being sold on the market and an inexpensive version is of interest to me especially since I have the ability to directly compare it to a commercial unit. Suppose we consider this as a form of peer review?
A good beginning would be to open the commercial unit and take a few pics. As it appears from Scott's link, the coil is not very critical and i would think, neither is the waveform. As i prefer having a frequency display, or at least a source of an accurate frequency i will forgo the 555 and rather use a microcontroller.
You are right one could simply take a look but I don't own the unit and I would not ask the owner to take his brand new toy apart just so I can rubber neck. That aside there is not much satisfaction in simply making a clone of another persons work and effort. Besides there are photos of the Revive on Six Moons which clearly show both sides of the very simple circuit board design that they use and it would appear to be a 555 based design. I do like your idea of a micro controller and it would permit easy adjustment but that is a bit to complex for my non electronic brain. Of course if you can figure one out and wish to share a schematic that would be nice. My concern with the wave form would be from the generation of odd harmonics from the square wave but you may be correct in your assumption that it may make little difference. What are your thoughts on the duty cycle of the square wave, wide or narrow?
I was going to edit the above post but my time window has lapsed. The more I think about it the more I think that a reverse saw tooth wave form would be a very good place to start. Many sounds in nature start with a peak and then have a decay. This may sound a bit corny but it seems a very natural envelope and the square wave even as a sharp pulse does not strike me as natural at all. So a sharp attack followed by a steady decay. Thunder comes to mind. Might be as good a choice as any.
I had also thought that the generator should have an assortment of target frequencies such as Theta Beta and Alpha as in sleep calm and alert stages of your brain wave patterns. Perhaps a setting for 45 33.3 and 78 would be attractive to the analog crowd.
I had also thought that the generator should have an assortment of target frequencies such as Theta Beta and Alpha as in sleep calm and alert stages of your brain wave patterns. Perhaps a setting for 45 33.3 and 78 would be attractive to the analog crowd.
It only makes sense to have pulses of very short duration in order to avoid heating up the coil and transmitter or you can capacitively couple the coil and obtain the same result. Or use a sine. No clue if it may be better.
When you suggest to capacitively couple the coil I take it you mean by winding one coil directly over the other? Can you explain your comment above "that capacitively coupling will obtain the same results". I think that if a decent size transformer (VA rating) is used it should be able to handle a 555 at full output. You are probably right that a short duration pulse is a good logical place to start for a project like this then experiment later once things are working.
CD player used as generator
Hi analog_sa,
The first was my function generator. With this equipment, the frequency change with temperature. Even if Schumann resonance is 7.83Hz +/- 0.5 Hz, you can hear difference when varying the frequency from 0.01 Hz.
For an accurate frequency, I use an old CD player where I burn a continuous 7.83Hz sine wave. For the antenna, I put a 10mH inductor (from my stock) with a 600 ohm serial resistor onto the analog output.
I plan to build a generator with microcontroller, more friendly than CD player.
Correct me if I'm wrong, but the 555 is not able to provide a signal with 50% duty cycle. It generates 7.83 HZ with other high frequency.
Hi analog_sa,
I try different solutions for a Schumann resonator.
The first was my function generator. With this equipment, the frequency change with temperature. Even if Schumann resonance is 7.83Hz +/- 0.5 Hz, you can hear difference when varying the frequency from 0.01 Hz.
For an accurate frequency, I use an old CD player where I burn a continuous 7.83Hz sine wave. For the antenna, I put a 10mH inductor (from my stock) with a 600 ohm serial resistor onto the analog output.
I plan to build a generator with microcontroller, more friendly than CD player.
Correct me if I'm wrong, but the 555 is not able to provide a signal with 50% duty cycle. It generates 7.83 HZ with other high frequency.
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These two site have lots of info on the 555 device. What size of area coverage do you get using the single 10mH coil? I will look forward to any and all micro controlled designs that may spring from this thread as I said that type of design is beyond my skills in electronics. I would be useful to have a device with multiple frequency settings and perhaps even various wave form settings. Thanks for the input Eric.
555 Timer/Oscillator Tutorial
555 timer
555 Timer/Oscillator Tutorial
555 timer
Some designs definitely use a 555. Acoustic Revive, otoh, do not. Just reversed their circuit (from pics in the review) and will draw and up it tomorrow if laziness does not prevail. The 8 pin device seen on the pics turned out to be a dual opamp. First half works as a relaxation oscillator and the second as a bandpass filter in order to turn the square waves into something prettier. A low pass should be equally effective. Split power is derived from the incoming 12v dc from two zeners and a virtual ground, so effective PS is probably +-4.7v. It seems AR gets better reviews than simple square wave generators so a sine wave is probably better. The pcb seems quite nice but component cost is way below $10 with the PS. Add a pcb and a case and total manufacturing cost is still under $40. No idea how much advertising and net buzz cost but they seem to operate on a pretty healthy markup.
Hello Moray,
- external diameter 44mm
- height 21mm.
Oh, I see that I don't use 10mH but 1.2mH inductor! Sorry. The size of coil is:
- external diameter 44mm
- height 21mm.
Hi analog_sa,
.
In this schematic, the oscillation frequency can vary with the value of the power supply and temperature.
I already do this search
.In this schematic, the oscillation frequency can vary with the value of the power supply and temperature.
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