Author Topic: "Real" Color DMD?  (Read 14949 times)

ecurtz

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"Real" Color DMD?
« on: December 20, 2014, 11:49:22 AM »
These are getting close to the size of a regular DMD (3mm vs. 2.54mm). Maybe not an issue with HDMI capable Raspberry Pis and BeagleBoards, but still pretty cute.

https://www.adafruit.com/products/2279

Brian Madden

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Re: "Real" Color DMD?
« Reply #1 on: December 20, 2014, 03:10:15 PM »
I cannot express how much I *don't* like color DMDs for the sole reason that they're LCD, so the colors don't pop as much and the blacks are sort of gray.

So I've always fantasized about doing an DMD with RGB LEDs like this. And at $90 each, two of them side-by-side to make a 128x32 display are still cheaper than an LED pinball DMD. Obviously it would be great if the pitch was more like a traditional DMD, and we'd have to figure out how to drive them, but I like this a lot.

So thanks for giving me another thing for my experimentation "to do" list. :)
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Rosh

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Re: "Real" Color DMD?
« Reply #2 on: December 22, 2014, 11:20:29 AM »
I cannot express how much I *don't* like color DMDs for the sole reason that they're LCD, so the colors don't pop as much and the blacks are sort of gray.

So I've always fantasized about doing an DMD with RGB LEDs like this. And at $90 each, two of them side-by-side to make a 128x32 display are still cheaper than an LED pinball DMD.


I understand the brightness thing, but if you are doing full color stuff vs just colorized dots, it is not really the same issue and I think it looks sufficiently bright (although certainly not as bright as these things would be)

The price of an LCD DMD setup is cheaper that the $180 you would pay for two of these. Don't confuse colorDMD prices for what LCD  hardware costs.  In the case of colorDMD there is a lot more to it then just a display unit. 

MOcean

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Re: "Real" Color DMD?
« Reply #3 on: December 22, 2014, 12:08:39 PM »
You'll need to add two Arduino Mega's to your pricing to drive these funky RGB board here.  I'd be very curious to see a build involving them, including complete source code, so don't let Rosh dissuade you!

Brian Madden

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Re: "Real" Color DMD?
« Reply #4 on: December 22, 2014, 12:18:47 PM »
I'd be very curious to see a build involving them, including complete source code

hehehe.. I think you've cracked the "Brian" code. :)

I've ordered these. Haven't thought about how I'll drive them yet. I have a BBB here which I might try first. Also need to find 8 amps @5vdc. Anyway I'm not even looking for these to have an immediate use.. call it "R&D" or something and then we'll see what comes from it.

BTW this is longer term for me. My plate is full, so who knows when I'll get to this. A few months I would guess.
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Brian Madden

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Re: "Real" Color DMD?
« Reply #5 on: December 22, 2014, 01:12:31 PM »
Oh man, so I just checked AliExpress for the heck of it. First of all, they have similar panels for under $40. (I couldn't find the 3mm ones in 32x64, though I found 5mm at that resolution and 3mm 16x32 for $8.)

More importantly, there seems to be some sort of standard connector & protocol for these types of displays, because there are also all sorts of controllers available that can drive varying numbers of pixels and that have the 16-pin connector (or several of them) that these displays need. So I think the Adafruit is kind of hacking / bit banging it to drive it with an Arduino. I'll see what I can find with the "real" controllers. Seems like they're all sort of geared to be standalone, where you load images and display effects onto them and then they run by themselves. But I might be able to find something that I can access more directly.

It would be cool if I could find a driver board that could treat this as a normal video output.. then it could just be a normal display on the computer (or even the top 128x32 corner of a display of the computer).

Anyway the reason I'm so keen on this is I have an idea for a pinball machine that starts out with everything black & white and then the player has to "earn" the color, one at a time. So obviously all the inserts and GIs are RGB, but for this to work right the DMD has to be RGB also, and again I just don't love the look of LCD-based DMDs, so that's why I'm so excited about this. :)
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Mark Jarzewiak

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Re: "Real" Color DMD?
« Reply #6 on: December 22, 2014, 01:36:05 PM »
While I do like ColorDMDs, I understand the dislike for the grey background.  I do the coloring on both my desktop (crappy cheap Acer monitor) and on the macbook (dual booting windows 7 64) 2008 unibody.  I wish a display like this existed in DMD size format.  The blacks are black, but it would definitely be an expensive monitor.  Just too bad something like this doesn't exist. 

fantasygoat

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Re: "Real" Color DMD?
« Reply #7 on: December 22, 2014, 10:29:13 PM »
I did a bit of research into alternative displays - something in the form factor of a DMD but perhaps twice the resolution (ala Flipper Football's display) and full colour, and I found 1mm RGB LEDs:

http://ca.mouser.com/new/lumex/lumexrgb0404/

Although maybe not small enough for a double res display, they'd be ideal for a full DMD replacement, but the problem for me is I'd need to do SMT and placing all those LEDs by hand... oi.

It would be awesome for someone with more hardware experience to make fully RGB DMDs.

Brian Madden

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Re: "Real" Color DMD?
« Reply #8 on: December 22, 2014, 10:37:15 PM »
I looked into that too. Unfortunately at 38 cents each (even in quantities of 10,000), you're looking at $1500 for a 128x32 display. :(

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fantasygoat

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Re: "Real" Color DMD?
« Reply #9 on: December 24, 2014, 01:06:55 AM »
Hmm, good point.  But I bet the manufacturer offers a better price!  I mean, how else is Adafruit selling that 3mm model for only $80?

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Re: "Real" Color DMD?
« Reply #10 on: December 24, 2014, 12:17:00 PM »
I mean, how else is Adafruit selling that 3mm model for only $80?

You know.. I just burned an hour on AliExpress based on this statement, because you make a good point! I did find small RGB LEDs that were about 1.5mm square for 7 cents each. So now we're talking $286 for a standard pinball DMD. Of course you'd still need to design a board, stuff it (with 4k components!), figure out the control circuitry, etc. I guess if you wanted to go into production then you could probably just get one of the other panel makers to build a smaller pitch one. But man, suddenly that 400 bucks for an LED DMD doesn't seem too bad!

All this effort because I don't like the look of a backlit LCD... Maybe my effort would be better spent with a high saturation LCD and a filter sheet. :)
Brian
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Mark Jarzewiak

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Re: "Real" Color DMD?
« Reply #11 on: December 24, 2014, 09:58:46 PM »
I mean, how else is Adafruit selling that 3mm model for only $80?



All this effort because I don't like the look of a backlit LCD... Maybe my effort would be better spent with a high saturation LCD and a filter sheet. :)

Might be a good idea.  Knowing Randy's obsession with providing a top-notch product with little sacrifice I know he is/has been/will continue to - look for better display panels.  Without going WAY up in price I think he's tried to maintain really good quality.  Unfortunately the not total black background is a detractor but games still look better in color than monochrome.

Brian Madden

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Re: "Real" Color DMD?
« Reply #12 on: January 07, 2015, 02:09:33 PM »
Just got the color RGB panels in. They are not a big as I thought. (In a good way!). Retrofitting an existing machine would require a new speaker panel, but they would fit on a pinball machine fine and I don't think too many people would even notice the size difference. The dots might be too far apart to look good.. we'll have to see.

This is a low priority project for me, but still.. progress.

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fantasygoat

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Re: "Real" Color DMD?
« Reply #13 on: January 07, 2015, 02:20:06 PM »
Hmm, I've noticed how bad the fitment of those segments are on some Stern games.  You'd think they'd try harder to get them to line up!

But that panel looks quite good!  Is it the same resolution as the DMD?

Curbfeeler

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Re: "Real" Color DMD?
« Reply #14 on: January 07, 2015, 02:37:38 PM »
Have a pic of the back and/or a link to what it is?  I'm intrigued, but I'd rather be informed :)

EDIT: I get it now.  Two of these -

https://www.adafruit.com/images/970x728/2279-01.jpg
https://www.adafruit.com/images/970x728/2279-02.jpg

I can't pick up on the line in the middle from this picture.  Very promising!
« Last Edit: January 07, 2015, 02:46:54 PM by Curbfeeler »