I used to have a little biofeedback oscillator that I think was Radio Shack (but, that was 20+ years ago and the mind plays tricks).
Anyway, it was simple to use and effective. I'm trying to find a schematic (I'm sure it was simple as it was probably designed in the '70s). It had 2 rubber cups, similar to spark plug lead end cups, that slipped over 2 fingers and wired into the box. It had a single operational control which allowed adjustment of the oscillator frequency. To use, you'd adjust the oscillator to some frequency and then try to relax to reduce the pulse rate (sounded like a square wave). If the frequency got too low, you'd readjust the oscillator and continue. I'm sure it reacted to skin galvanic response or something similar.
I tried Googling it but, it seems like most results were for the $1k+ professional units and the associated text was high-falutin' medical lingo.
Seems like something that could be done with a 555 timer. Does anyone out there have some experience with this device or something similar? Or...a circuit design or ideas?
Thanks
Anyway, it was simple to use and effective. I'm trying to find a schematic (I'm sure it was simple as it was probably designed in the '70s). It had 2 rubber cups, similar to spark plug lead end cups, that slipped over 2 fingers and wired into the box. It had a single operational control which allowed adjustment of the oscillator frequency. To use, you'd adjust the oscillator to some frequency and then try to relax to reduce the pulse rate (sounded like a square wave). If the frequency got too low, you'd readjust the oscillator and continue. I'm sure it reacted to skin galvanic response or something similar.
I tried Googling it but, it seems like most results were for the $1k+ professional units and the associated text was high-falutin' medical lingo.
Seems like something that could be done with a 555 timer. Does anyone out there have some experience with this device or something similar? Or...a circuit design or ideas?
Thanks
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