[sdiy] About that spherical impulse generator...

[harrybissell]

I bet you would find that the triangular piezo bits would cost less than you
think...
they are not off the shelf, but to make a large sphere, you would need several
hundred, enough for a custom order with no problem. they are not really that
high tech.

I forget the company who made this, but there is also piezo polymer materials
used for hydrophones, sonar apps etc.  I used to have a sample of it...maybe I
still do and can find the company name. That sh!t was NOT cheap.

It would be pretty hard to attach all the electrode wires, think of that as
well.
Also... why not hexagons instead of triangles... that is close to the existing
round
brass shapes...maybe enough to use the round ones and trim them.

You have to consider the vibtatory modes of the discs... they are usually
mounted
at a nodal point and flex like a drumhead. Bind them at the edges and you might
be right
back to the beaming problem

Have you just considered explosives ???   ;^P

H^) harry

Glen wrote:

> Here's a follow up idea that John Mahoney and I both had:
>
> Would a truly spherical piezoelectric transducer be practical?
>
> One potential approach would be to take a brass sphere and coat it with the
> piezo material they put on the piezo discs. But since that material is
> crystalline and faceted, I'm not so sure it would like "wrapping" around a
> brass sphere.
>
> Alternately since quartz is piezoelectric, zap a crystal ball with high
> voltage. (There's a joke in there somewhere.) It would certainly be easier
> to get the crystal ball than a custom-built piezo sphere.
>
> I'm afraid that since the piezo material is a crystal structure with
> definite "facets" to it, that it might not expand equally in all
> directions. It might be just as well to cover a geodesic dome with piezo
> discs.
>
> For a better fit, use triangular piezos instead of discs. I wonder if it's
> possible to cut the discs into triangles yourself? Use a Dremel tool,
> perhaps? I know it's a lot of work, but how much would custom-built piezo
> triangles cost? (A lot, I bet.)
>
> later,
> Glen Berry