>
> I am emailing the Pic Microcontroller Discussion list to
> request help in locating galvanic skin response (GSR)
> circuit designs.
>
> My motivation here is to help a family member with a
> rare, and life threatening health disorder, whose process
> begins with increasing perspiration while sleeping.
>
> The end result of one of these episodes is similar to a
> very severe epileptic seizure.  Needless to say that this
> family member's health severely deteriorates with each
> occurrence, including some close brushes with death.
>
> So identifying GSR circuit designs is key to developing
> a microcontroller based device to "alert" family members
> of this condition, and take actions, such as give medication,
> ..., etc.
>
> Herein lies the reason for this email.  While various web
> search engine searches have uncovered some "hobbyist"
> level GSR schematics, I cannot judge the quality, or
> reliability of the circuitry.
>
> So here are a few ideas on how PICList readers could be
> of assistance:
>
>  - Can you think of any useful & reliable GSR designs you may
>    have seen in the past ??
> -  Note that since GSR's are one of the key sensors used in
>    polygraphs or lie detectors, maybe you have seen something
>    as part of projects under those names.
> - Are you aware of any university or research work in this
>    area ?
> - Can you think of any useful reference design sources ??
> - Who are some of the more knowledgeable circuit designers
>   you have come across ??  Where can you refer me ??
>
>  Thanks in advance for your feedback and suggestions.
>
> Sincerely,
>   Peter Krey

>Many magazines have had reasonable quality schematics for "Stress
>detectors" etc., IIRC Popular Electronics had a schematic for one such a
>while back.
>
>  Lots of issues to be aware of here:
>
>  This is a Life-Critical type system - you want to make sure this thing
>works & works well & reliably & doesn't have lots of failure modes.
>
>  For one:  You want either a WELL-isolated power supply, if you're
>going to plug this unit into AC power (And I don't mean a typical "Wall
>Wart", I mean something that's certified for medical use!) - OR, you
>want to use a deep-cycle lead-acid battery (probably a better choice!)
>like a golf cart or marine trolling battery as a power source, due to
>the possible danger of electric shock.  (Some power supplies have been
>known to have a catastrophic failure mode where when they fail, they
>output 117VAC to the Vcc and ground output leads - The Dauphin DTR-1
>laptop is one such - you don't want a family member wired up to this
>with a taped-on electrode, then shocked while asleep, rather
>obviously!)  I'd lean towards a nice deep cycle lead-acid battery, with
>a few days extra capacity if possible (should be!) for probably much
>less than an isolated supply.  And charge it every other day or
>something, but only when not attached to the family member.  Safe
>isolated power units may be cheaper than last I worked with Spacelabs,
>though.
>
>  You'll need to find a good source of the electrodes (The only source I
>know of, is those off of one web page that I cannot find right now -
>it's about using muscle firing rates to input signals to your computer
>instead of a keyboard, I cannot remember the acronym they were using
>right now, they use some reasonably cheap electrodes, I do remember.)
>It'll be in Alternate input methods off http://wearables.org/ someplace,
>bug me if you cannot find it.  Aaah.  SMUT, that's the acronym.
>Something or other, Motor Unit Training.  That's about watching motor
>neurons cycle rates etc., not skin galvanic response, but I suspect the
>electrodes are transferable.
>
>  How do you run wires from the family member to the device?
>Alternately, could use wireless & strap a small unit to the family
>member, battery powered, but then you want some sort of regular "ping"
>from the unit to the receiver (you want to know that the sender's quit
>working!), could be done with IR or RF.  Either way has problems &
>advantages.
>
>  What sort of alarm do you want?  How do you calibrate for summer
>versus winter? (Want to prevent false triggers from too much blankets,
>or those really hot nights.)  Might use 2 sets of electrodes or
>something?
>
>  I'm a little distracted (getting set to do job search here), so I
>may've missed any number of things.  In a time rush, want to try to
>catch some people about a job <G>
>
>  Mark
>
>Peter Krey & Family wrote:
>>
>> I am emailing the Pic Microcontroller Discussion list to
>> request help in locating galvanic skin response (GSR)
>> circuit designs.
>>
>> My motivation here is to help a family member with a
>> rare, and life threatening health disorder, whose process
>> begins with increasing perspiration while sleeping.
>>
>> The end result of one of these episodes is similar to a
>> very severe epileptic seizure.  Needless to say that this
>> family member's health severely deteriorates with each
>> occurrence, including some close brushes with death.
>>
>> So identifying GSR circuit designs is key to developing
>> a microcontroller based device to "alert" family members
>> of this condition, and take actions, such as give medication,
>> ..., etc.
>>
>> Herein lies the reason for this email.  While various web
>> search engine searches have uncovered some "hobbyist"
>> level GSR schematics, I cannot judge the quality, or
>> reliability of the circuitry.
>>
>> So here are a few ideas on how PICList readers could be
>> of assistance:
>>
>>  - Can you think of any useful & reliable GSR designs you may
>>    have seen in the past ??
>> -  Note that since GSR's are one of the key sensors used in
>>    polygraphs or lie detectors, maybe you have seen something
>>    as part of projects under those names.
>> - Are you aware of any university or research work in this
>>    area ?
>> - Can you think of any useful reference design sources ??
>> - Who are some of the more knowledgeable circuit designers
>>   you have come across ??  Where can you refer me ??
>>
>>  Thanks in advance for your feedback and suggestions.
>>
>> Sincerely,
>>   Peter Krey