Need help with laser project

I have a project, I am trying to convert the X/Y/Z (blank) signals from a circuit designed to output to a vector scan monitor and redirect them to laser either by galvanometer/PC interface/anything possible to active this..

Can you help direct me to resources or the best way to do this? This is for a single laser output (one color). The problem also is that I want to increase the axis range dynamically so that I can project on a wall, building, anything....

Thanks for any helpful suggestions! Anyone for hire to help do this???

-Craig snipped-for-privacy@hotmail.com

Reply to
Craig
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There was a similar project a few years back, laser MAME which was an emulator of vector arcade games. The problem is that galvos have physical mass and inertia, so the characteristics are quite different than that of a vector monitor. If you can emulate the hardware on a PC that's probably your best bet. There won't be a simple hardware converter.

Reply to
James Sweet

I seem to recall that Elektor magazine did an x-y laser projector a couple of years back, and that a kit was done for it. Might be worth you posting on their website forum. Also, the actual mechanics and drive electronics to do this are readily available at very reasonable prices form the likes of Maplin here in the UK. They are used for disco lighting purposes, and respond to the music, but as far as I know, the effect is achieved by having an x-y mirror unit driven by stepper motors. I would have thought that it would not have been terribly difficult to suitably scale and condition the analogue x-y drives for a stroke writing monitor, to suit the mirror drive circuitry of such a ready-made unit, and sub your laser into the optical path in place of the lamp unit.

Arfa

Reply to
Arfa Daily

It used a couple of DC motors to generate semi-random patterns using a laser pointer

Reply to
GPG

Open up a damaged cd or dvd player. It has a nice lens arrangement which you can use to move around/tilt a small piece of mirror you glue on top of the lens. Then feed the small coils with all sorts of signals, and have fun with it. As you are only changing the angles, just stay far away from the target, and you will get a nice big picture field. (Oh and don't you or other people look into the laser beam) For safety, you can make a small detection circuit, to check for the presence of AC voltage on the coils, and use that to switch on/off the laser. That increases your safety manifold.

Reply to
Sjouke Burry

Oh I forgot one way to do this very easily, glue pieces of mirror to two small loudspeakers, then bounce the laser form the first mirror to the next mirror, and use a stereo amp, and music to move the mirrors/speakers.

Reply to
Sjouke Burry

James Sweet wrote in news:cX4Mh.11668$e47.4988 @trnddc05:

This was my initial thought: too much mass, too much inertia, slow response.

But loudspeakers are really "linear galvanometers", and their frequency response is quite good. Might be fun to figure out how to change a mirror angle with an old speaker.

Old hard drives used a moving-coil in a magnetic field to scan the sensor across the disk--another opportunity to turn an old part into an interesting experiment.

Reply to
Jim Land

the vector crt signals are too fast by a factor of six or more for even the best galvos, you'd have to recode the source to add delays, considering, if this is a vector game, the vector generation timing and scaling is always partially hardcoded in hardware,so you have a BIG problem. Also crts don't have blanking points, buffer points, extra corner points, all needed by even the fastest galvos, and most vector systems, with the exception of a few that do sliding stroke writing,(ie charge a integrator to the new point voltage) return to center in between objects, the return to center is fine for a blanked electron beam, but it confuses the heck out of the galvos. btw, as you expand scan size, you need to slow down the scan rate.

galvos have inertia,electron beams for practical purposes dont.

the other way to do it is use a AO deflector pair, but thats megabucks.

I know the fellows that did laser mame, and its not easy. plus if your using game code, its a most excellent way to get sued. Laser Mame passed the points from a emulated game to a pangolin card that drove the galvos, and that is probably the best solution. Galvos limit out at about 700 points in a image.

if its military, like a flight simulator, start here:

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then
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if thats not fast enough

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neos makes a nice 512x512 XY deflector, so does

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probably Crystal technology and Brimrose do as well.

none of the mentioned hard drive motors, modified speakers etc will get you anywhere close to the speed of a true galvo with feedback I used to earn my living doing vector graphics with lasers.

Steve Roberts

Reply to
osr

By design, the lens does not tilt significantly. It moves up and down (focus coil) or side-to-side (tracking coil).

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Reply to
Sam Goldwasser

Lougspeakers don't change angle but only translate (at least ideally). Any angle change is a byproduct of non-linearities in the system.

There are relatively inexpensive galvos that will do the X and Y at low speed.

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Reply to
Sam Goldwasser

That won't do what he's asking, for vector graphics one needs expensive high speed closed loop galvos and drivers.

Reply to
James Sweet

A pair (one for X, one for Y) of mirror galvanometers is the standard way to do this, although they can be tricky to drive to useful speeds. I once built something similar 15+ years ago, but I obtained my galvos by scavenging them from the laser tracking mechanism of an obsolete laser-disk player, so I'm not sure where you'd buy them these days. Depending on your laser, the distances you're working with, & the amount of deflection you require, it might be possible to adapt the equivalent assembly from a DVD burner. (Some of the have very nice high power, visible red laser diodes built into a (possibly) suitable servo mech.)

Do you just want to build one, or do you want to go into production? What kind of budget do you have to work with? Feel free to email me if you want to discuss this privately.

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Reply to
Lionel

A magnet to scan the field operate in the mhz range and is real complicated. The exact transform to operate as an x,y or z value may be operated and the circuit output behave oddly.

If an x,y, or z value is desired to be applied to the laser the science is applied art.

Here is what I would do to have fun.

A scan coil is removed from the side of the CRT. All the wires overlapping in the exact geometric center may safely be spread apart. Making a hole thru which to pass the HeNe tube!

What happens is as you request! And x scan causes the x modulation frequency of the HeNe , the y the y-mode and z the z-mode.

So you have three channels to modulate with x.

Apply the frequency to the circuit to cause frequency modulation.

Reply to
Douglas Eagleson

What about a scan converter ?? sample the high data rate x/y/blank signals into a buffer with some vector/corner detection to "extract" the useful coordinates, then output a low rate stream to the galvo scanners, adding corner points to square things up -- DSP should be up to the vector/corner detection, and a microcontroller can handle the slow scan output. One of those DSP/MCU combos should be quite capable of the task.

Reply to
John Barrett

Raster conversion with X and Y smoothed stepper motors (similar to existing multi-frequency monitors) sounds like the way to go. I could develop it, but can you afford me (and my team)?

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Reply to
joseph2k

Isn't thise really a 2D problem, not 3D?

I've bought the mirror deflectors from bar code reader at the local fleamarket. Of course, that is only 1D.

Reply to
miso

the Z in this case is a TTL blanking signal -- turn the beam on or off while the scanners poition to the start of a new vector.

Reply to
John Barrett

Tried to email you off group but the message bounced -- drop me a line if you are still looking for someone to take on this project.

Reply to
John Barrett

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