I've seen them triggered by the pendulum, and they work nicely.









Jeffrey D Spears <jspears@ENGIN.UMICH.EDU> on 04/14/2000 06:28:06 PM

Please respond to pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>








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 Subject: [OT] More on piezo-electric generation please








Craig;

Last fall term at an electromagnetics class demonstration, the TA
used a high voltage piezo contraption to charge great big capacitors.
It developed ungodly numbers of thousands of volts. After the demo,
I immediatly went and picked the thing up and started fooling around
with the thing. The TA was very fidgity about me playing with it.
He said: Watch out! That thing is going to get you! It was a small
hand operated thing with a big heavy wire and electrode.

What really surprised me about this high voltage *sparker* (for lack of
good term) is how it felt. When I squeezed the handle, it felt mushy. I
always thought peizo materials are strictly hard crystals. Something
that can undergo stress--hit with a hammer as you say. Evidently this
is not always the case.

Also, did you know some folks pronounce it pee-aay-zo? Prior to the
EM course, I pronounced it pee-zo.


If you are interested in efficient solar cell experiments, check out
BEAM robots. Search for BEAM on your browser. Its a whole clan of
folks that build little solar powered robots using simple timing
circuits and huge capacitors--its really cool! My first BEAM project
is going to be a solar powered pendulumn  that hangs in my window.
The solar cell will charge a super-cap which will get dumped into
a coil that propels the pendulumn via permanent magnet. The timing
circuit will be set to the resonate frequency of the pendulumn. Or
maybe it will be triggered directly by the pendulumn. Will try both.


ok..jef



On Fri, 14 Apr 2000, Craig Lee wrote:

> I find these alternate energy threads fascinating,
> especially due to the latest ransom we've been expected
> to pay at the pumps!!!
>
> Someone mentioned generating a watt of power from stressing
> a crystal.  Can someone offer a practical procedure where
> one could start experimentation with this.
>
> Just think of a flashlight where one could hammer on it to
> make it work.  This is what we do anyway when the bulb goes,
> but with white leds, not a problem anymore.
>
> Technological advancement; got to love it!
>
> Craig
>


Jeffrey D. Spears
University of Michigan
College of Engineering

``Double-E, can't spell gEEk without it!''
                        -Captain Gerald M. Bloomfield II, USMC
                         (my brother)