My whole projector goal... help!

[allthatwhichis]

I have to admit, I really only have one goal in mind for my projector. I've mentioned it before but I don't think I have been explaining it well. I've gotten a few open loop set ups to get close, but never gotten that perfect representation so that's why I went to closed loop but it seems my idea will be even harder to obtain with closed loop galvos, but cannot get the detail or perfection from open looped ones...

I want a laser osilliscope, it is my true laser obsession... I want my projector to do show a true repsentation of a sound's waveform.

Here is a screen shot from mediaplayer with the "scope" visualisation and it is exactly what I am looking for, well, it's only in green, I'd also like to have the color change with sound pitch if possible. But that opens up other cans of shitte...



If there any software that will do this? Help, please... :?

[cruch]

I have played around with pangolin's plugin for winamp.
It can produce what you have mentioned. Pluss alot more!

I can take som pictures of it later if you want ?

Thanks to PANGOLIN a new world has been discovered

[Zoof]

I know exactly what you mean because I have been playing around with the same idea when I was into my speaker scanner system setup (long time ago). Before I built a DAC I had just one speaker with mirror connected to my stereo providing a waveform. Now all that was needed was a linear time signal on the other axis. A cam-shaft kind of setup had that purpose. It was basically a wheel shaped such that as it made a revolution it pushed the mirror out and then snapped back in becuase it was spring loaded. So that was the horizontal time axis while the speaker provided the waveform along the vertical axis. It worked pretty well for slow speeds, maybe 5-7 frames per second

OK that $5 solution is no match for your setup but I also remember trying to write a winamp plugin ( yeah I know Pangolin ran off with that idea ) for the homebrew DAC that I was building. It was a random visualisation of the music but the synchronisation was very much off and the plugin was too inconsistent to provide a timely stream of points into the LPT DAC. I dropped the whole project. But if you have some programming skills (and time) you should be able to find the code for winamp plugins and can give it a shot.

Thinking about it... I'm not sure if this is something you want to try before checking with the experts but you could connect your Y scanner input an audio signal and provide a linear time signal to X input through the DAC with any laser show software.
Would it work?

[allthatwhichis]

cruch... :P I knew someone would say pangolin... I don't have any first borns to sell at the moment. :roll: but when I do, pangolin is definatly one of the reaons to sell. :twisted:

zoof, seems like we have walked similar paths. I have a motorized 1st surface mirror that has 8 or 10 sides that I tried using with a speaker mirror for the Y axis but I couldn't get the speed down enough. It looked like a big horizontal line that bounced. I think the key is the fps, slow like you mentioned. or have a kid and... well... :roll: i don't think a speaker has the resolution either, at least not at high frequencies.

I went to school for videogame development and they taught us c++ but I don't really enjoy programming. There is a visualization program for winamp that does very close to what I would like, it uses thee waveforms I think, or it looks that way, and it is written in c. The first version from 99 came with the source code in the zip. I was thinking of asking the writer which part is just for the wave, and if I could use it. This is all dependent on finding a use for the code. I'm way out of practice and really don't like to code.

I'm also not sure if I could align the open loop y with an audio input close enough to the scanner x. Although that is a good theory. Just have the x scanner go back and forth drawing a horizontal line. Might even be able to interpolate the line at a certain "bit rate" by how many points are in the line... :idea: Still a mounting feat... I was told DO NOT hook an audio signal to the closed loop scanner, so I cannot use it's convienent locaiton... That's why I'd like to find a software solution that might scan the music file, grabe it's waveform from that and just draw it with the scanners. :roll: That's "inexpensive"...

[dave]

With appropriate filtering i guess you could hook up a audio signal to a set of scanners, although im not entirely sure what the cutoff frequency would need to be, and what order the filter would need to be.....

[allthatwhichis]

:lol: Thanks dave, but if you don't know, I doubt I could dream of it... :?

I think the easiest way would be to get a plugin for winamp that would just draw whatever wimamp's visualization plugin was displaying.

[jkaiser3000]

I think you could accomplish this with your galvos plus a speaker mounted mirror. Use the speaker mirror as your Y axis, and the galvos as the X axis. That way, you can control the speed at which the laser is scanned in the X axis to match it with the Y scanning.

It's a bit of an archaic approach and the response curve will not be that good either, but should work.

[Spec]

I had fun with this idea a while ago

Polygon scanner for the X projection axis and open-loop "Gal-2" for the Y projection axis.

What you really need is a "tall mirror" polygon scanner to catch all the deflection from the "Gal-2"

Your image above: the waveform, looks like it would require closed loop galvos to have the tight response needed for the sharp peaks. Getting almost any closed loop galvo to eat the low level PC soundcard output would be trivial.

Another thing: the Polygon scanner pictured below spins at about 7000 RPM, you would need to adjust the speed and position to get the *exact* effect and position you want. I did notice that with the 6 sided mirrors I could almost get 120 degrees X axis deflection.

[DZ]

cruch... I knew someone would say pangolin... I don't have any first borns to sell at the moment. but when I do, pangolin is definatly one of the reaons to sell.

But of course!

http://video.google.com/videoplay?do...62901569&hl=en

David

[allthatwhichis]

Dammit man that's it... :P You bringing that next week? I think it's time to have another sale on eBay... That's 2 vots for the big P, and no other suggestions... I'll have to sell everything but one computer, the lasers and the scanners...

I do have a motorized first surface mirror scanner thing...





But it move fast. It stops altogether at a certain voltage, but the sides are almsot an inch tall.