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Thread: Announcing ILDAC-32 - an ESP-32 based DAC for ILDA projectors

  1. #21
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    Question I can't believe some of these replies...

    Quote Originally Posted by masterpj View Post
    You lose resolution through color balancing often.
    Did you read the description of the project before you posted? There is no color balancing.

    Let's back up for just a moment. The concept for this device started out as a self-contained, battery-powered box that, when connected to a laser projector, would create a slowly moving dot for a lumia effect. That's it.

    Later, Hank decided it would be nice if the unit could also display a few test patterns, because he thought that might be useful if you wanted to do a quick test on your projectors. (Remember: portable, battery-powered, and self-contained.)

    Then he figured it wouldn't be too much more work to put together a simple web interface to select the frames. OK, but now it's not exactly self-contained anymore, is it? Still, he felt it was worth the trade-off.

    Once that was working, he added the ability to play short ILDA animations. Then he put together a cell-phone app to control the device. He's also tweaked the code to increase the point speed, added some waveform and color choices, and plenty of other tweaks.

    At this point, we are already *WAY* beyond the initial design criteria of a self-contained, battery-powered device that makes the slow moving dot that he originally wanted for the lumia effect. It has a built-in webserver. It supports WiFi and Bluetooth. It's got an SD card reader. There's a dedicated phone app. And considering that we're talking about something that costs ~ $150, that's pretty incredible.

    But let's be frank: re-mapping 8-bit color data from your ILDA frames into a 12-bit color space AFTER you apply color correction and white balancing is a *VERY* advanced feature that even Pangolin hasn't implemented on any of their hardware yet. Do you really think this should be a priority for a hobbyist device with these design goals, especially when the device doesn't have any color correction to start with (and was never meant to have it)?

    Yes, if you save an entire laser show as a string of ILDA files to the SD card, you can use the ILDAC-32 to play the show (sans audio, obviously), and you can trigger the playback either from a web browser or from your smart phone. But the whole purpose of this project was not to build a controller that would replace whatever device you currently have connected to your computer for running laser shows. If someone wants to turn this into a dedicated controller (perhaps by implementing the full Etherdream protocol), then that's cool, but again, this was never the goal of the project.

    Quote Originally Posted by mixedgas
    After making color correction curves for my latest projector I see about 30% laser energy un-used with 8 bit dacs. 10 or 12 bits can really improve that.
    Agreed. Are you volunteering to write the code to enable color correction curves for the ILDAC-32? Because that was never part of the design criteria (why would it be?). The control software does not support any sort of color correction. (Watch the videos that Hank posted above.)

    More to the point, if the "Scaley Anteater" company hasn't implemented this feature yet, what on earth makes you think it's something that would be appropriate for a $150 hobbyist device?

    I'm absolutely dumbfounded by these replies... Hank has created a clever unit that ended up being capable of a whole lot more than he ever intended for the project, yet you guys are asking for features that aren't present even on controllers costing 10X more. Seriously guys - WFT?

    Adam

    EDIT: After getting some rest, I re-read through this post this morning and realized that I sound like a self-righteous dickhead. Sorry about that. I'm still upset about Ed Keefe's passing, and I let those feelings cloud my judgement. I should have waited to post this until later.

    Also, upon re-reading, it occurred to me that it's possible that you both assumed that Hank was simply passing the standard 8-bit color data from the ILDA file format directly to his 12-bit output DACs without first up-scaling the data. If he had done that, then yeah, you would lose a huge amount of brightness at the top end. Although this would definitely qualify as a rookie mistake...

    Fortunately, Hank was aware of this potential problem. The 8-bit color data is up-scaled to match the 12-bit output of the digital-to-analog converter outputs; thus max brightness in the 8-bit ILDA frame file still yields a full +5 volts on the output of the 12-bit DAC.

    Note, however that this is strictly a linear scale conversion (multiply by 16); there is no color curve or white-balance adjustment.
    Last edited by buffo; 02-08-2022 at 06:26. Reason: Gave it some further thought.

  2. #22
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    They are suggestions not demands naturally with the idea to future proof (if it's possible off course!).
    I don't see the response of asking for more resolution as weird/offensive seeing someone working on another dac entering the market (as there are many people who like to see more resolution on color channels) Assuming the dac eventually can be interfaced with programs that have advanced color control.

    The sollinger dac has a higher resolution per color channel (24 bits to be exact!). But it also attributed to it's size off course https://laseranimation.com/en/products/avb-devices

    The ILDA file spec is indeed 8bits color.. but the colors are presented as an "ideal situation" without assuming any form of color balancing so if you have to color correct after the fact (mentioned or not) some of that information gets lost in quantization as you scale down your max color output.

    Is color curve balancing advanced?: Yes, but just setting a min and max is an option too (could be done with an opamp per channel as well!). To achieve certain colors/gradients/fades you are going to be confronted with it eventually (or with projector age when diodes module powers start drifting apart differently). If it affects the price point: I'd cut it right away from the todo's sure. However since lumia which often involves a slow/fine color control.. it seemed quite handy and future proof to attempt to go for it.

    The price point of $150 is amazing off course and if it would make it fall from the budget then it's one thing that should off course be compromised one.. but if it can be done: Why not? I think people are also speculating the cost of these slightly higher bit dacs to have gone down (suggested by the cost of 12bit dacs on ebay)

    Why didn't pangolin do it? (speculation): DAC total size or component options given at the time of design is a very likely bet. I do know the QM uses opamps to scale the min and max (if that's for each color channel other then X/Y I dont know).
    Last edited by masterpj; 02-07-2022 at 19:25.

  3. #23
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    Let me take a second to clarify what ILDAC-32 is and was meant to be. Well, Adam actually did a fine job explaining that above (thanks).

    But what I can add here is that perhaps I have been using the term "DAC" here a little loosely because to me, that's just what it's doing D to A C. But it is not a "DAC" in the sense that it's a full-fledged laser controller like all the other products in the market that are called "DACs". So that's 100% on me and I apologize.

    So folks, please don't think of this project as a "Laser-Show-Controller-DAC".

    Now if down the road we are able to get it to use the Etherdream protocol to receive show content from other software over Wifi, it would be a DAC emulator. But as I mentioned above, that's a little ways off.

    Here's how I described ILDAC-32 in the first post, with one small modification:

    I have created an entirely self-contained DAC^H^H^H test pattern and lumia generator based on ESP-32 that runs test patterns, lumia cues, static beams, and ILDA files/animations to any ILDA compatible laser projector. Controllable via Bluetooth with a mobile app, and/or any web browser over WiFi using the internal web server.

    Perhaps we can try to focus on all the things ILDAC-32 can do, instead of what it can't? Thanks.
    Last edited by HankLloydRight; 02-07-2022 at 20:10.

  4. #24
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    Many of the Chinese projectors have support for DMX or SD cards and those parts can be had really cheap. Why not just leverage something like that?

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    Quote Originally Posted by JohnYayas View Post
    Many of the Chinese projectors have support for DMX or SD cards and those parts can be had really cheap. Why not just leverage something like that?
    I'm not sure I understand.
    Can these projectors be controlled via built-in web app over wifi or a mobile app over Bluetooth?
    Can these projectors let you dynamically and remotely adjust the scan rate, scan size, blanking shift, brightness, and X/Y offset?

  6. #26
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    Quote Originally Posted by JohnYayas View Post
    Many of the Chinese projectors have support for DMX or SD cards and those parts can be had really cheap. Why not just leverage something like that?
    I think you're suggesting that it would have been easier to buy an inexpensive Chinese projector that supported playback from an SD card and just use that projector for the lumia display, rather than building the ILDAC-32, right?

    In that case, then yeah, it probably would have been easier. (For sure it would have been faster!) But when he first started this project, Hank had no idea that "feature creep" would morph it into what it has become today. Initially he figured he could have something working in just a few weeks. (Which he did, at least before the scope started to change.)

    You also have to consider the allure of a new project: he was keen to see if he could build a self-contained unit that would do what he wanted. He also liked the idea of being able to use his existing projectors, rather than buying or building a dedicated projector just for lumia. (I actually suggested the idea of building a dedicated lumia rig at the start of this project.) In the end, he decided to start down the path of building a little battery-powered box to get the job done, and like so many hobbyists, he just kept adding things to it until it had morphed into something very different from what he started with.

    Adam

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    Quote Originally Posted by HankLloydRight View Post
    I'm not sure I understand.
    Can these projectors be controlled via built-in web app over wifi or a mobile app over Bluetooth?
    Can these projectors let you dynamically and remotely adjust the scan rate, scan size, blanking shift, brightness, and X/Y offset?
    I wasn't suggesting to buy the projector, just the dmx/sd portion. I think you can probably get them from gumball machines in China.
    They don't have the features you mentioned... at least not all of them, but, depending on what you really need to achieve, they might be able to suffice.
    I suppose it's a moot point now, since you have already developed something.

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    Quote Originally Posted by buffo View Post
    I think you're suggesting that it would have been easier to buy an inexpensive Chinese projector that supported playback from an SD card and just use that projector for the lumia display, rather than building the ILDAC-32, right?

    In that case, then yeah, it probably would have been easier. (For sure it would have been faster!) But when he first started this project, Hank had no idea that "feature creep" would morph it into what it has become today. Initially he figured he could have something working in just a few weeks. (Which he did, at least before the scope started to change.)

    You also have to consider the allure of a new project: he was keen to see if he could build a self-contained unit that would do what he wanted. He also liked the idea of being able to use his existing projectors, rather than buying or building a dedicated projector just for lumia. (I actually suggested the idea of building a dedicated lumia rig at the start of this project.) In the end, he decided to start down the path of building a little battery-powered box to get the job done, and like so many hobbyists, he just kept adding things to it until it had morphed into something very different from what he started with.

    Adam
    No, I was just suggesting the use of the DMX/SD controller portion, which should be available for a very low cost. I do get the allure of a DIY project, though.

  9. #29
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    Buffo, if down the road he wants help with a six or eight (or more) point flat slope correction curve, the fit for each segment is Intensity out = M*Icommanded + B

    Aka Y = mX+B from good ole Algebra class. M will not always be an integer, but a fractional, probably a Float16 or a Float32 so that may eat up processing time.

    Slope and offset from each breakpoint location, now interpreting where you are on that line segment in software can't be that bad.

    I'll do my best. If I can remember what Sister Suzanne taught me in ninth grade. AT my age that might be tough as I never use it in the day job, anymore.

    Peter,

    QM32 uses a Dac chip to drive the Reference Pin of a Dac Chip and or Multiplying DAC Chip for scaling, color, etc. It is the most beautiful image size control I have ever seen. But expensive unless you can find a MDAC with a lot of consumer application. The reason for doing it that way is near zero loss of resolution in the image. Good XY needs a minimum of 10 bits for the eye in the near field while not controlling image size with the DAC. . Pangolin, back in the day, ran tests according to Pat Murphy.. Semiconductor prices for good parts are unreal right now.

    Steve
    Last edited by mixedgas; 02-08-2022 at 16:50.
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  10. #30
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    Quote Originally Posted by mixedgas View Post
    Any possibility of adding WAV to ILDA for XYRGBS where s = spare or timecode and optional.
    Steve
    Ask and ye shall receive.

    Over the last month or so, I've now hacked in a fourth 12-bit DAC to the three DACs already on the ILDAC (see pic below).

    I've also added code to play, with stereo audio, any 44.1kHz or 48kHz 16-bit WAV file content (scaled down to the 12-bit DACs). To answer any questions a head of time, the unit plays the XY/RGB/Left/Right WAV channels.

    Have some WAV files or an entire show you want to play? Put it on the SD card, and select the file to play, or "Play All" to play all the WAV files in any directory on the SD card. No other computer hardware of software necessary (other than any desktop or mobile web browser) It's that easy.

    So now the ILDAC-WAV can display all the standard test patterns, several test shapes and beams and a lumia cue. And thousands of ILDA files in the Photolexicon FTP collection. And now almost any WAV file show content.

    I'll be sending initial ILDAC-WAV prototype PCBs out to be made in the next few days. Once the new boards are built and tested, I'll be offering them for sale for $199 each (price subject to change based on current chip prices). Once the new ILDAC-WAV version is tested and available, I'll be selling the existing Ver-1 ILDAC-32 without WAV functionality for $100. I have five V1 units left.

    I have a demo video with a few clips of WAV files being played, but since it contains copyrighted content, please PM me if you would like to see it.

    -Hank

    Click image for larger version. 

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    Last edited by HankLloydRight; 04-01-2022 at 23:27.

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