Re: As a hobbyist where can I get 'cheap' Pyroelectric crystals?

A pyroelectric crystal develops a surface voltage separation with changing
temperature.  The voltage difference can be large.  The crystal must be an
electrical insulator so the available amperage is small.

 http://en.wikipedia.org/wiki/Pyroelectric

http://www.azom.com/details.asp?ArticleID=3593

http://www.manep.ch/en/technological-challenges/ferroelectrics.html

The most accessible home-growable pyroelectric crystal is Rochelle salt
(NaKC4H4O6.4H2O, sodium
potassium tartrate tetrahydrate).  Between its two Curie points of -18�C
and +24�C, it is ferroelectric with a monoclinic point group 2. In the
non-ferroelectric region it is in orthorhombic point group 222 and only
shows piezoelectricity.

Properties of Rochelle Salt
Phys. Rev. 47(2) 175 (1935)
Polymorphism of Rochelle Salt 
Phys. Rev. 51 43 (1937)
Properties of Rochelle Salt. III
Phys. Rev. 58(6) 565 (1940)

WARNING! There are three different types of tartartic acid! 
L-(+)-(2R,3R)-Tartaric acid is the natural stuff from grape
lees.  D-(-)-(2S,3S)-Tartaric is the mirror image and rather
expensive.  DL-Tartaric acid (racemic tartaric acid) is a mixture of both
*and will not work* to give pyroelectic crystals.  If you must work with
hot basic solutions, work rapidly.  Grow crystals from warm solution

 http://seawhy.com/xlroch.html

http://seawhy.com/xlrs.html

H. Hope, "Apparatus for growth of crystals for X-ray diffraction study"
J. Appl. Cryst. 4 333 (1971)

 http://www.sciencekit.com/images/250/62/S6240900.JPG

http://wardsci.com/images/100/172141webM.JPG
Thiele-Dennis tube

More reasonable:  Take a beaker, stably mount it with a 20-30 degree
rotation off vertical.  Mostly fill with solvent (distilled water). 
Saturate with solute.  Add more solute (signficant excess) to the
bottommost corner and apply mild heat right there, toward the side.  Seal
top with plastic wrap and a pinhole (air pressure vs. temp).  A
concentrated convective plume will rise up the side, cool to
supersaturation, and descend down the middle or so (you can see refractive
wiggles by looking through the side).  When everything is at equilibrium
and there is still substantial solid at the bottom, suspend your perfect
seed crystal in the descending plume.  A very tiny drop of waterproof epoxy
at the end of 2-lb test fishing line or a thick human hair will secure the
seed crystal and controllably suspend it in the supersaturated descending
plume.  Rotate as necessary to keep growth symmetric.  On what seed crystal
face should you attach the filament?