DIY Holograms

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DIY Holograms

Paul Holman
I'm trying to remember who the presenter was at one of our early  
Dorkbot meetings who talked about making his own holograms with a  
compass?  He brought some he'd made to show around too.

Anyone remember?

Thanks, pablos.
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RE: DIY Holograms

Kate Seekings
Bill Beaty - billb AT amasci (dot) com

http://amasci.com 

K

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Paul Holman
Sent: Sunday, March 12, 2006 11:47 PM
To: A discussion list for dorkbot-sea
Subject: [dorkbotsea-blabber] DIY Holograms

I'm trying to remember who the presenter was at one of our early  
Dorkbot meetings who talked about making his own holograms with a  
compass?  He brought some he'd made to show around too.

Anyone remember?

Thanks, pablos.
........................................................................
.........dorkbot: people doing strange things with electricity..........
..........................http://dorkbot.org............................
........................................................................

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.........dorkbot: people doing strange things with electricity..........
..........................http://dorkbot.org............................
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Re: DIY Holograms

Paul Holman
On Mar 13, 2006, at 12:18 AM, Kate Seekings wrote:

> Bill Beaty - billb AT amasci (dot) com
>
> http://amasci.com

Of course.

Thanks,

pablos.

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.........dorkbot: people doing strange things with electricity..........
..........................http://dorkbot.org............................
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RE: DIY Holograms

Steve Greenfield
In reply to this post by Kate Seekings
I'm thinking this could be done with a plotter with a scratch tip
or a sign cutting blade. The tough part (for me) would be the
programming necessary.

http://amasci.com/amateur/holo1.html

Steve Greenfield

--- Kate Seekings <[hidden email]> wrote:

> Bill Beaty - billb AT amasci (dot) com
>
> http://amasci.com 

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RE: DIY Holograms

Bill Beaty

Also see:

  http://amasci.com/amateur/holohint.html

  http://amasci.com/amateur/hand1.html


At 07:59 AM 3/13/2006 -0800, you wrote:
>I'm thinking this could be done with a plotter with a scratch tip
>or a sign cutting blade. The tough part (for me) would be the
>programming necessary.


It's been tried.   Doesn't work.   The curved scratches must be mirror
smooth, or at least a good approximation.  The jaggies from a stepper-
based XY plotter are way too big.

If the scribing tip even makes a little *noise* as it moves, then
the ripples from that "phonograph recording" will foul up the optics.

Scribing by hand with a compass works fine, as long as the tip is not
too sharp  ...and as long as the tip doesn't go "EEEEEK" as it moves.

I tried using an ancient analog plotter (with gearmotors and feedback pots)
but it had backlash-type errors where the feedback loop would constantly
oscillate a bit as the motors encountered nonlinear friction and didn't
compensate.   A feedback loop would have to be extremely "rigid" and
high gain, yet more than neutrally damped.

I suspect that a variable-radius spinner device is needed.  Then the
spinner would be moved around on an X-Y transport.







((((((((((((((((((((((( (  (    (o)    )  ) )))))))))))))))))))))))
William J. Beaty              http://staff.washington.edu/wbeaty/
Research Engineer             UW Chem Dept,  Bagley Hall RM74
[hidden email]     Box 351700, Seattle, WA 98195-1700
ph:206-543-6195 fax:206-685-8665

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RE: DIY Holograms

Bill Beaty
In reply to this post by Steve Greenfield
At 07:59 AM 3/13/2006 -0800, you wrote:
>I'm thinking this could be done with a plotter with a scratch tip
>or a sign cutting blade. The tough part (for me) would be the
>programming necessary.
>http://amasci.com/amateur/holo1.html




A couple years ago a guy from SA (Argentina, I think) sent me photos
of his hand-made attempts.  These images float inside the surface but
are flat, except for the rose/butterfly where the flat rose is at
a deeper depth.

Scorpio
http://amasci.com/graphics/olocompasso7.jpg

Woman w/rose
http://amasci.com/graphics/olocompasso9.jpg

Jesus
http://amasci.com/graphics/olocompasso10.jpg

Roses w/butterfly
http://amasci.com/graphics/olocompasso11.jpg





((((((((((((((((((((((( (  (    (o)    )  ) )))))))))))))))))))))))
William J. Beaty              http://staff.washington.edu/wbeaty/
Research Engineer             UW Chem Dept,  Bagley Hall RM74
[hidden email]     Box 351700, Seattle, WA 98195-1700
ph:206-543-6195 fax:206-685-8665

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..........................http://dorkbot.org............................
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RE: DIY Holograms

Steve Greenfield
In reply to this post by Bill Beaty
--- Bill Beaty <[hidden email]> wrote:

>
> Also see:
>
>   http://amasci.com/amateur/holohint.html
>
>   http://amasci.com/amateur/hand1.html
>
>
> At 07:59 AM 3/13/2006 -0800, you wrote:
> >I'm thinking this could be done with a plotter with a scratch
> tip
> >or a sign cutting blade. The tough part (for me) would be the
> >programming necessary.
>
>
> It's been tried.   Doesn't work.   The curved scratches must be
> mirror
> smooth, or at least a good approximation.  The jaggies from a
> stepper-
> based XY plotter are way too big.
>
> If the scribing tip even makes a little *noise* as it moves, then
>
> the ripples from that "phonograph recording" will foul up the
> optics.
>
> Scribing by hand with a compass works fine, as long as the tip is
> not
> too sharp  ...and as long as the tip doesn't go "EEEEEK" as it
> moves.
>
> I tried using an ancient analog plotter (with gearmotors and
> feedback pots)
> but it had backlash-type errors where the feedback loop would
> constantly
> oscillate a bit as the motors encountered nonlinear friction and
> didn't
> compensate.   A feedback loop would have to be extremely "rigid"
> and
> high gain, yet more than neutrally damped.
>
> I suspect that a variable-radius spinner device is needed.  Then
> the
> spinner would be moved around on an X-Y transport.

Hmmm... Fantastic idea. Just move the center to points along the
shape you are drawing, and scrape a semi-circle. Change the radius
as you detail to change apparent depth.

Steve Greenfield
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Re: DIY Holograms

Chuck Harrison
In reply to this post by Bill Beaty
[...]
> >I'm thinking this could be done with a plotter with a scratch tip
> >or a sign cutting blade. The tough part (for me) would be the
> >programming necessary.
>
> It's been tried.   Doesn't work.   The curved scratches must be mirror
> smooth, or at least a good approximation.  The jaggies from a stepper-
> based XY plotter are way too big.

OK, that sounds like a challenge. Smoothness uber alles, eh?

Of course we know that mechanical design is fundamentally up to
the task; look at the "ruling engines" that inscribed extremely
high quality diffraction gratings (sub-sub-wavelength regularity)
long before holographic production methods became available. The
question is how to do it simply and elegantly.

One thing that comes to my mind is setting the scriber upside
down (the bottom surface of the plate is being scratched) and
immersing the whole X-Y mechanism in a bucket of gear oil...

A DC servo driving a smooth-shaft linear actuator, using optical
feedback from the moving carriage, can be quite smooth and
precise. http://www.zero-max.com/products/rohlix/rohlixmain.asp .
Years ago I used different manufacturer's actuator, where the
shaft runs *inside* the bores of three large tilted ball-bearings.
This was really slick but I can't remember who made it.

What about driving the scriber in the X axis, and the substrate
in the Y axis, so both actuators/slides can be anchored directly
to the machine frame?

Cheers,
  Chuck
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.........dorkbot: people doing strange things with electricity..........
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