Laser marking/directing system

Traditional old school way to do it would be two axis mirror galvos and analogue signals to determine the position of the laser dot.

There are some toy laser projectors that can put a diffraction pattern very like a cross onto a target and some fairly bright white light LED torches that can focus the LED die onto a target at about that range. If you can make a mask for one of those then you can nail it.

This is a rather pretty colourful example of the technique using Venus as the light source and a fine fabric as the diffraction mesh.

So you are intending to make these to sell as opposed to a one off?

My money would be to project the cross pattern with Fourier optics so there are no moving parts and it is very cheap to make.

I can get cheap servos:

But how to align mirrors to translate those servos to xy plane

Yes. If my idea pans out I will be selling a, lot of them

I have not heard about Fourier optics before. I need a max deflection of maybe 45 degrees. So I am guessing it would not be usable

My next suggestion then would be two laser light sources projecting a point of light and a cylinder lens to spread it out along a line.

To try it out crudely just find some clear Perspex or glass rod.

On a sunny day (Sat, 18 Dec 2021 17:53:04 +0100) it happened Klaus Kragelund snipped-for-privacy@hotmail.com wrote in snipped-for-privacy@nntp.aioe.org>:

Use RC servos and 1 PIC micro red laser diodes are cheap on ebay.

Or you could get one of those xy movable video security cameras and put a laser diode on it. Wrote a controller for mine long time ago. Then you have the camera pointing at the target all the time.

On a sunny day (Sat, 18 Dec 2021 18:37:49 +0100) it happened Klaus Kragelund snipped-for-privacy@hotmail.com wrote in snipped-for-privacy@nntp.aioe.org>:

5 cheap red laser diodes make a cross: I bought ten for what was it? 2$58 in 2914, so now they ask 6$89...

Can a radio control servo move fast enough to fool the eye?

piglet

laser pointer with a holographic slide that creates an "X" I recall buying something like this for under $10 retail.

Alternatively laser, beam splitter and two cylindrical lenses. or if for some reason you can't get a cheap beam splitter two lasers and two cylindrical lenses (or cylindrical reflectors if you can't get lenses, warp a small mirror, or wrap aluminised mylar on a drink can etc.)

This will probably work better than the cheap hologram, as the cheap ones tend to bleed a lot of the original beam, thus producing a bright spot on the main axis. (these are dollar-store trinkets, I have not tried a professional quality hologram)

Or back towards your original plan two lasers and two mirror galvanometers connected to an AC supply (5V?) add a potentiometer to control the size of the "X"

I then need to find a camera with an open SW/library. How did you go about finding the documentation for controlling them?

Klaus Kragelund wrote: ===================

** RC servos cannot reverse direction near fast enough for your idea. Small mirrors mounted on a speaker cone are far better. The speakers could be driven with low voltage 60Hz.

..... Phil

lørdag den 18. december 2021 kl. 17.53.09 UTC+1 skrev Klaus Kragelund:

I actually found a video of exactly what I want. With 2 servos, and quite fast

He cleverly attaches the two bodies of the servo:

Another one here, with 2 small mirrors:

snipped-for-privacy@gmail.com wrote: ==================

** Really ?

Why the f*ck did you FAIL to mention the laser generated pattern could be NON VISIBLE visible to the eye ??

..... Phil

I don't get what you mean about non visible. It's visible in the video?

snipped-for-privacy@gmail.com wrote: ==================

** It's a f****ng, slow moving dot - imbecile !

" a laser marking system, that can show a cross hair or other visible marking "

Does not compute, captain.

..... Phil

You can buy holographic reticles that do that. A laser sight for an airsoft gun gives you the laser pointer as well.

(Disclaimer--I've used reticles like that, but have never used a laser sight, so I don't know how suitable it is for the purpose.)

Cheers

Phil Hobbs

Phil Allison snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

There are swivel mounted mirrors out there with a coil already on them which can be modulated to hard point or oscillate the mirror angle.

I used to put 'music' up on the ceiling with my HeNe laser tube, and two such mirrors.

Phil Allison snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

You sure do mumble a lot. Meaningless shit too.