On 1/15/2018 4:47 PM, wrote:
On Mon, 15 Jan 2018 13:47:33 -0500,
wrote:

On Mon, 15 Jan 2018 02:23:21 -0500, wrote:

On Sun, 14 Jan 2018 23:37:16 -0500,
wrote:

On Sun, 14 Jan 2018 22:09:37 -0500, wrote:

45 years ago I was in a bar in Chicago and they had a laser deal that
plotted the 2 channels of the sound system as a Lissajous pattern on
the back wall.
I tried to make one using an old Neon laser and mirrors on speaker
drivers about 40 years ago. It was almost working when the free used
laser I had crapped out. Now that laser diodes cost less than a stick
of gum I wanted to try again. What is the best way to steer the laser?
Piezo crystal or some kind of mirror solution


===

I'm not an expert on piezo crystal optics but I think you'll have more
fun engineering an electromechanical linkage to a mirror. It will
also be more intuitive and use readily available components.


That was my thinking before I started working on laser printers but
these days it is a pretty mature science and those parts may be as
cheap as lasers. I found out the first time down the rabbit hole, you
need a 1st surface mirror. A regular silver on glass mirror creates a
ghost image. I ended up with a dental mirror sans handle, epoxied to a
coil spring with arms going out to 2 small speaker cones 90 degrees
out. The laser I had was a neon, about 1.5" in diameter and a foot
long that needed a HV power supply to spark up. These days you can get
a diode that runs on 4.5vdc. Just about the time I got the geometry
right, my laser broke.
I came up with another laser down here but it was pressed into service
at the flower store and went with the store. That design was still a
little funky and I wanted to try something different.
I really don't believe that in the 70s they were using a crystal tho.
We did us one in a 3800 but it only deflected in one axis.
I may be missing a whole different concept in steering a laser. I
thought Richard may have dabbled in this stuff.


===

I'm assuming you'd need two mirrors - one for X axis positioning and a
second for the Y axis. There are lots of devices with fairly bright
lasers these days. Perhaps you could get one on EBAY or at a garage
sale. Of course you'd need to be happy with either red or green. I've
got some green gun sight lasers that are fairly bright, and there are
lots of laser pointers around that are allegedly bright enough to
blind aircraft pilots.

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The 2 mirror solution was my first thought and I tried it with regular
mirrors but the glazing caused the ghost problem.
My second swing at it was a single mirror that I could swing in 2 axis
with a spring as a center pivot. That was a 1st surface dental mirror.
Just when I was starting to get results the laser quit and I shelved
the project.
These days the laser is the trivial part. Red and green laser diodes
can be salvaged from old pointers or simply ordered as a part, dirt
cheap. You can also scavenge some very powerful blue lasers from DVD
drives but they are strong enough to be a serious eye hazard.

It has been pointed out to me that you can just get a "visualization"
file for a MP3 player that does this exact thing on a big screen TV.



The only laser "pointer" system I had any participation in (in a small
way) was the 500 terawatt (no typo), 192 beam NIF laser at the Lawrence
Livermore National Laboratory. (LLNL) Many of the beam handling optics
for the laser bay received optical coatings using one of the optical
coaters my company built. We originally built the system for the
Laboratory for Laser Energetics (LLE) at the University of Rochester for
a similar, but smaller, 60 beam laser system. When LLNL solicited
optical coating services to supply the coated optics for NIF, nobody
except the LLE could meet the power and damage specs. It was quite a
feather in our and the Lab for Laser Energetics caps for a while and we
ended up with additional contracts directly with Lawrence Livermore.

Both the NIF laser system and the Omega laser system at the LLE UofR
fire a multi-beam, high power laser from multiple but symmetrical
directions onto a tiny "target", compressing it. In the case of the NIF
system, it creates a nuclear fusion reaction by compressing hydrogen.

High tech stuff that I only understand the surface level of.