Electronic experts or simply someone who know how to do this!

Discussion in 'The Projects Forum' started by Karenzee, Mar 6, 2015.

  1. Karenzee

    Thread Starter New Member

    Mar 6, 2015
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    Hi,


    First of all i hope you'll excuse grammar mistakes, i'm still learning english!


    I first posted on the diy audio but my dad suggested this forum.


    I'm a member of a junior audio club and recently discovered the accoustic revive through the father of another member.

    Our funds are very limited, so i plan to build a portable sine wave generator based on a schematic i found.


    I already etched a small pcb antenna (with help from my dad).


    My plan is to make it available to others members of the club (they'll need to solder though).

    My issue is that i would need help to design/redraw the circuit, the rest i can take care of.


    This circuit might interest other diy enthusiasts too!

    This is the link to the schematic


    Thanks and take care!


    Kenzi.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    So, the 1988 date on the drawing makes me think it has been tried and proven to some degree. Many upgrades are possible but that is up to you.

    There are many options to create the PCB. You can draw it with a felt tip pen onto paper and scan it, or, a more professional option would be to use free software like Eagle, DesignSpark or many others. There are video instructions, and many tutorials online. I am sure you would enjoy doing it yourself.
     
  4. Karenzee

    Thread Starter New Member

    Mar 6, 2015
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    Hi Dodgydave and GopherT!

    i looked at wien oscillator (thread and schematics) and i see that some people mention distortion of the sine wave, do you confirm that?

    GopherT,

    The antenna is already etched, i used toner transfer method with good results (second try with help!)for the circuit i still find CAD complex but i'm sure it's great!

    on another forum someone mentioned mp3 players to play those frequencies, what do you think?

    Thanks!
     
  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    If you just want to generate audible tones, the freeware program Audacity can do that.
     
  6. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Does it have to be a Sine wave,if not use a 555 timer oscillator instead, a lot simpler.
     
  7. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    The LED symbol on the schematic is the wrong symbol, and it is pointing the wrong way. Must have been very new technology to Mr Walonich in 1988 ;)

    What is it used for?
     
  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    She is at 10 Hz and 7.83 Hz. Won't those frequencies get filtered by most sound cards?
     
  9. DickCappels

    Moderator

    Aug 21, 2008
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    The circuit will not work well if it works at all as shown in the link. The circuit is designed for a dual power supply (V+, V-, and common or ground) but it is shown as using a single positive power supply only. If you want to save as much of the PCB design as possible the quickest fix for that problem is to add a negative regulator to the uA741 pin 4. You can make a negative power supply by adding a battery with the positive terminal going to the common or ground connection and the negative terminal going to the LM741 pin 4 and putting a capacitor from the negative terminal to ground.

    What do you want different from the original circuit besides the power supply being corrected or the circuit correct to work with a single supply so it can work? What frequency do you want? Any other features desired?
     
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Good point. Didn't spot the frequency values on the schem.
     
  11. Karenzee

    Thread Starter New Member

    Mar 6, 2015
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    Hi!




    Yes Dodgydave we are trying to reproduce the accoustic revive device (but portable), but i will also test it with 555 square wave generator that i have built!




    DickCappels, a simple (if possible) sine wave circuit generating a fixed 7.83 frequency with no distortions (if that is possible!)


    I don't have much information on the circuit of the accoustic revive except that it mention sine wave pulsed (pulsed might be more complex)


    Thanks!
     
  12. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The frequencies you want are so low that most commercial devices (phones, tablets, mp3 players, computer sound cards, etc.) will not do a good job. Their software might say they are generating the frequency, but the output stage and coupling components might attenuate it below a useable level.

    As mentioned above, the circuit will not work as drawn because the 741 requires either a negative voltage supply at pin 4 or a DC bias circuit at pin 3.

    The pc board in the device photo is very well done, and an excellent example of good layout technique. However, it is not the same circuit as the one you posted.

    A Schumann resonance frequency sine wave with low distortion is hard to achieve because of the energy storage required. A standard Wein oscillator with a light bulb to stabilize the output amplitude usually is the best circuit for low distortion, but in your case it would need a light bulb with a large filament (larger thermal mass) and take a long time to stabilize.

    This is the perfect forum for you to get the circuit help you need, but keep in mind that there is zero credible evidence that Schumann devices do anything useful in the field of electromedicine.

    ak
     
  13. Karenzee

    Thread Starter New Member

    Mar 6, 2015
    15
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    Hi AnalogKid,

    I know i didn't see the actual circuit of the accoustic revive (i have seen one but not open), it is described as generating sine waves (pulsed) but people who tried to reproduce it generated square waves. (so we could try both!)

    We are trying to reproduce if we can, the effect of the accoustic revive or similar device at a lower cost (if we can!) and judge the results ourselves, it's a fun and interesting project! (what is the field of electromedicine?)

    Thanks for your help, you shared very interesting informations!
     
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