R. Michael O'Bannon wrote:
> <snipped>
> Here is a basic design idea:  A small, thin piece of absorbant tissue
> <snipped>
> and the tissue thin.  The circuitry use could be the type used for rain
> detectors.  This has been discussed recently on the list.
>
> Perhaps other on the list can clean this idea up a bit.
>
> Best regards,
> Michael
>
> R. Michael O'Bannon, Ph.D.
> Clinical and Corporate Psychologist
> Atlanta, GA

  I was thinking along the lines of turning an RF transmitter ON when
you detect that there's conductivity between those electrodes, perhaps
instead of a tethered Lead-Acid battery a 9V Ni-Cad on the person in
question would be a good power supply, running the Pic.  Then when you
detect a wheatstone bridge type conductivity change due to sweat, fire
the transmitter.

  Could almost couple a weak AC signal into a "Solar Racer" type
circuit, and when conductivity skyrockets, you know you have lots of
sweat, but ideal rectifiers are not easy to find <G>

  How's THIS for a Totally LOW tech method:  The "Clothespin switch"
method:  If you have a small salt crystal that's held against the paper
that's against the skin, and the salt crystal is holding a microswitch
OPEN, and could basically guarantee that it'd wick up sweat & dissolve
it & close the switch "on cue", you could just use a "Sonalert" and a 9V
battery & a switch.  Might have to run the paper along one or both jaws
of the switch assembly, to make the sweat travel to the crystal properly
- This'd be nice & portable & completely tetherless, and reasonably
cheap, just some labor to make salt crystals.  (Use Rock salt for the
hold-open?  Or a saccharine or "Equal" tabler, or rock candy crystal, or
some other substance that's easy to clean up & doesn't make TOO much of
a mess?)  Clothespin switch with metal on both faces might even just
conduct enough to run the PIC when the salt gets wet enough <G>  I was
thinking of having a sealed microswitch, though, and have the
microswitch allowed to close when the jaws close past a certain point.

  (If your circuit could be small enough, could even *glue* it in place
on an appropriate site - using a Lithium "Pin" type battery or two for
power, perhaps? - and charge a supercap up to speed before inserting the
Pin batteries.  Make the unit look like "Borg jewelry" <G>  Yeah, I'm
modeming WAY too late tonight! <G>)

  Mark