ILDA Format BS

[keeperx]

well i guess it comes down to laser art, and reproducing art with lasers.. for reproduction, all this makes sense.. but for laser art, analog is the way to go..

[drlava]

This digital galvo control is in the future, but it might come at a high cost to flexibility as well as your wallet if the right steps aren't taken now. Analog control offers the simplest and least expensive path to the scanners, it is so simple that there is hardly a way to NOT make it standardized across galvo amps. Geometric correction boards likewise easily plug into most systems without a fuss.

When you look at digital control, the possibilities for proprietary closed interface design are endless. The computer side digital controller/transciever, if there is hardware there, will not be compatible with other galvo systems the way DACs are. Want to build a geometric correction add-on? good luck. Want to split your signal to drive two projectors at once? good luck Want to display a show on your buddy's projector using your laptop with your show software? If he has different brand galvos, you're in for a treat of installing hardware/software to control them IF your show software maker has decided to bless that brand with compatibility. With analog, you just plug your DAC to his projector.

So, what needs to be done very soon is for ILDA to develop a standardized digital projector interface specification in a similar manner to the 25 pin interface specification they have developed for analog. The reasons they developed the analog specification still must be true today in the digital realm. In the end this will help to keep costs low and compatibility high, and prevent hardware lock-in. It would even help to improve safety because additional safety standards could be built in.

What I am thinking of is a high speed, long distance bidirectional digital interface specification for real-time control that may make use of existing CAT5 and CAT6 cabling as the analog DB25 standard made use of existing appropriate connector technology. 'DACs' of the future could still exist as these interface tranceivers on the computer side and on the projector side an interface receiver could be built in to the DSP galvos or separate D/A board there if one still wanted to use analog galvos. Analog control could be preserved for the lasers or the DSP galvos could produce the RGBXXX signals themselves and act as a built-in scanfail, blanking the laser output if there is a problem. DAC chips are not nearly as expensive as they were decades ago, making their incorporation into the DSP galvos (for RGBXXX control output) or the RGBXXX lasers themselves a definite possibility.

[keeperx]

well if its long distance i would say screw catAnything and go straight to fiber.

thats cool anyway, cuz its you telling a LED to tell you laser what to do..

[carmangary]

You're exactly right. No one should expect to see digital scanners come out and then immediately see them everywhere. There really is no reason for something like that in cheap disco beam show scanners. And, we can all get by without it since we already are. But, I bet the big dollar production companies that do work for DisneyWorld or whoever would love something like that and would have the money to pay for it. But, even if the majority of us can't afford it, they still have to invent a way to control these things. It may be (probably would be) proprietary at first but it would eventually become standardized. It ain't gonna be via WAV file.

Keeperz, why do you keep saying analog is the way to go. We're not talking about making digital images here, we are talking about using digital lines for control. There is nothing analog about what we all are doing here now. We are creating digital ILDA frames (or WAV files) and sending them digitally to a DAC or sound card. At that point it becomes analog with no relationship to what the scanner is actually doing. All we are talking about is making the relationship tighter so that the DAC or whatever DOES know what the scanner is doing and can react appropriately so that it doesn't draw ovals when it should be drawing rectangles.

[keeperx]

Im talking about ART and your talking about IMAGES....

LASER ART is not just lines on a wall.
laser art is beams in the air and abstract strange designs that ARE waves.

so like i said there is a difference between ART and REPRODUCTION.

[mixedgas]

one thing to remember here guys, if your scanner gets too fast, all you get is dots. Then you have to crank up the resolution to fill in the gaps, thus slowing down, and the best the eyes can see is about 10 bits in a laser image.

So its all about slew rate too.

You can already experience this with beam effects. In fact, its DESIRED in beam effects, A lot of what makes laser art good is the analog transfer function of the galvos with respect to time. )Opps, dont let James read that! (

I have two TI DMD demo kits, but I cant get the information out of TI on how to interface them, as I stumbled into older ones. So the next logical step is DMD followed in the beam path by scanners.

Steve

[carmangary]

Im talking about ART and your talking about IMAGES....

LASER ART is not just lines on a wall.
laser art is beams in the air and abstract strange designs that ARE waves.

so like i said there is a difference between ART and REPRODUCTION.

Ummmm. OK. I'm going to go back to listening to my sound art now on my radio.

[keeperx]

the live concert is better....

[The_Doctor]

Some assumptions here are that laser display will stay analog. As soon as a smart person creates a better galvo driver (perhaps one that offers feedback information to the host) with a bidirectional digital interface any argument of using WAV falls flat on the floor. However, the ILDA format would stay relevant because it is only a mechanism to define the points and not a way to send information to the galvos.

So long as there is a need for a cheap machine to move a mass that scans a beam, a previously rendered control signal, stored as a stream of data, is viable, and probably the best way to do it. Storage is cheaper than processing power.

When you have invented a scanner that can move without mass, then you can talk about something other than an analog motion.

[keeperx]

problem is that you NEED motion to DRAW a pic.. a laser is JUST A SINGLE DOT.. that image you see is in your mind.. the laser is onlu ever in1 place at any point in time.