MOTM

http://www.youtube.com/watch?v=3DFmXvFbWuc

Note that when Terry mentions "..the E350 is the filter..." this is
referring to what is used to drive the galvos (the E350 is a VCO in
reality). Normally, envelope-detected audio is used as the "filter" and the
galvos are swept by quadrature triangles (like a CRT raster sweep).

For those interested in replicating this setup: I will ask what galvos he is
using and what they cost/where to buy. Note several important things:

a) in the US, this sort of laser projector CANNOT be used in public unless
under very STRICT requirements.
b) professional "off the shelf" XY galvo pairs w/drive electronics and power
supply can run $1500. The galvos can require 3A peak each, and the moving
mass/inertia is large. The galvos are usually mounted on 1/4 in steel plates
(called optical plates) and then inside a matte black steel box weighing
10kg/25lbs to keep vibration 'errors' to a minimum. The box keeps spurious
laser deflections from "flying around the room" . These galvos are also very
fast and very accurate: they can move to 30,000 individual positions per
second (the mirrors usually have 45-55 degrees total travel) at 0.05 degree
accuracy.

Thanks again to Terry Ahrens for setting this up and making the videos.

Paul S.

That looks really great! Make sure not to miss the first one too:
http://www.youtube.com/watch?v=PkRC_b6zpSM

John L Rice

> -----Original Message-----
> From: motm@yahoogroups.com [mailto:motm@yahoogroups.com] On Behalf Of
> Paul Schreiber
> Sent: Tuesday, October 12, 2010 7:44 AM
> To: MOTM List
> Subject: [motm] MOTM laser video
>
> http://www.youtube.com/watch?v=3DFmXvFbWuc
>
> Note that when Terry mentions "..the E350 is the filter..." this is
> referring to what is used to drive the galvos (the E350 is a VCO in
> reality). Normally, envelope-detected audio is used as the "filter" and
> the
> galvos are swept by quadrature triangles (like a CRT raster sweep).
>
> For those interested in replicating this setup: I will ask what galvos
> he is
> using and what they cost/where to buy. Note several important things:
>
> a) in the US, this sort of laser projector CANNOT be used in public
> unless
> under very STRICT requirements.
> b) professional "off the shelf" XY galvo pairs w/drive electronics and
> power
> supply can run $1500. The galvos can require 3A peak each, and the
> moving
> mass/inertia is large. The galvos are usually mounted on 1/4 in steel
> plates
> (called optical plates) and then inside a matte black steel box
> weighing
> 10kg/25lbs to keep vibration 'errors' to a minimum. The box keeps
> spurious
> laser deflections from "flying around the room" . These galvos are also
> very
> fast and very accurate: they can move to 30,000 individual positions
> per
> second (the mirrors usually have 45-55 degrees total travel) at 0.05
> degree
> accuracy.
>
> Thanks again to Terry Ahrens for setting this up and making the videos.
>
> Paul S.
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

This can be done considerably more cheaply. I had posted this a while back on the make magazine blog:

http://blog.makezine.com/archive/2007/11/new_robotmakers_video.html

Cheers,
Roger

--- In motm@yahoogroups.com, "John L Rice" <Drummer@...> wrote:
>
> That looks really great! Make sure not to miss the first one too:
> http://www.youtube.com/watch?v=PkRC_b6zpSM
>
> John L Rice
>
> > -----Original Message-----
> > From: motm@yahoogroups.com [mailto:motm@yahoogroups.com] On Behalf Of
> > Paul Schreiber
> > Sent: Tuesday, October 12, 2010 7:44 AM
> > To: MOTM List
> > Subject: [motm] MOTM laser video
> >
> > http://www.youtube.com/watch?v=3DFmXvFbWuc
> >

Actually, there is a very reasonably-priced option to obtain brand new laser galvos complete with the drivers, power supply and 1/8" stereo jack that can be used with the E350 Morphing Terrarium:

http://www.midwest-laser.com/html/computer_controlled_laser_show.html

The system sells for $199 in kit form, and $263 assembled. It is capable of up to 2 kHz, which is more than adequate for use in the "Mid" frequency setting of the MT, with room to mix in another quadrature signal for added complexity (a software control program is also included). These are compatible for use in the US and Europe. I have found the customer service to be both friendly and helpful. Be sure to mention "MOTM" in the comments section if you decide to order. Feel free to contact me off-list if you need any pointers for setting this up along with your E350 and other synth modules. I will also post information about sources for lasers in the future.

P.S. For the record, I referred to the Morphing Terrarium as the *silver* module, rather than the filter module - filters have very limited use for controlling lasers.
~Terry