On Mon, 15 Jan 2018 16:01:40 -0500, "Mr. Luddite"
wrote:

On 1/15/2018 3:59 PM, Mr. Luddite wrote:
On 1/15/2018 1:47 PM, 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.Â* 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.Â* There are lots of devices with fairly bright
lasers these days.Â* Perhaps you could get one on EBAY or at a garage
sale.Â* 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.



Greg:Â* Check this out:

https://www.youtube.com/watch?v=qwawj0A8P6w


Or, for a more advance project:

https://www.youtube.com/watch?v=xszp5UQLB2g

I have a couple of those laser projectors you light up the front of
your house with that I got real cheap after christmas 2016. We have
one lighting up the trees out back, way cooler than shining one on a
flat surface but the other one stopped moving and I am going to take
it apart to see how they did it. I assume this is some kind of
motorized prism/mirror sort of thing. It splits the beam into about 64
separate sub beams that then get split into 64 more beams that expand
and contract around that point. I am sure that once I get inside I
will be amazed at how simple that thing really is.