Giant full color led display

[xorcise]

need led display

here is the projected RGB LED matrix board ,

all R , G and B LED terminals shorted and driven by same signal.

picture clear you more !

Then what are you talking about if not driving an LED Matrix? Do the math.... 640 x 480 x RGB = 80 x 60 of these blocks would be required. I have 48mm and 60mm RGB blocks, so that would easily become a VERY large display.

Also, your approach is too electrically simplistic. Firstly, your drawings (the ones I can see here in the forum) don't show a matrix configuration. Next, your circuit with the FET's cannot work due to the fact that each color LED has a different Vf. You would try to turn all 3 on at the same time and only one will light.

 

[blueroomelectronics]

how to make a color led display

Actually it's a start. Doing a small 8x8 matrix will give you an idea of the complexity of driving even a simple LED display. An 8x8 RGB matrix is the same as a 8x24 display and it starts getting complex after that.
manish12 your 640x480 RGB display is a pipe dream for any hobbyist, student etc. Can't be built on any sort of budget in a reasonable amount of time. The cost would be huge as would be the power requirements. I doubt you've done the math involved and what are you hoping to control it with? A video card? It's possible but have you considered what ICs you're going to use for the scan converter?
Interesting thread in theory only, but manish12's theories are based on guesswork not from experience.

 

[blueroomelectronics]

albert.li@huntingled.com

ok i quit !

thank you !

I had to quote it because you may delete or edit it. manish12 it's very poor form to edit or delete your posts and change them completely so they now appear out of context. It's ok to repair them as long as the main body hasn't changed.

Your original post indicated you were capable of such a design and would post it here, but you've re-edited that post too. We were all very excited about seeing a massive display and in full color too! but alas, you are just learning like so many of us. I've had decades of experience with electronics and I still learn something new every day. That's what makes electronics, especially microcontrollers so much fun.

We're all here in these forums to hopefully learn and build things based around electronics. Sharing is the key, we can all share our knowledge but try to share facts not speculation unless you say it's an theory or guess or whatever.

 

[drbizzarow]

rgb led brightness up down controller attiny2313

???

 

[blueroomelectronics]

lcd hd44 giant

???

manish12 deleted all his posts to this thread, simply replacing them with "sorry"

 

[manish12]

display hd44780 gigant

You haven't done your homework in this regard, have you?

You haven't shown or said anything here that that could be considered correct, even for a single RGB LED termination. You can stop pretending with your scribbles and jibberish.

Bill is right... this project is way beyond your ability and comprehension. You learn by doing something simpler first, like connecting and running a single small matrix. Even on a small level this type of project is beyond the conceptual ability of 99% of the programmers and hardware people who play with microcontrollers.

what else i have to do ?

 

[marwan naboulsi]

led screen syncing

stop that
all of us don't need to terminate this tread with no results
we can continue without blame pasicr ,cause he start while all of us wait some one to discuss such project .

any way we need to continue what pasicr start

and first we will discuss the concepts and make monochrome 640x480 led panel
i suggest to make first 640x2 line to test the hardware that we will make
i suggest to discuss this concept :

The screen refresh process begins in the top left corner and
paints 1 pixel at a time from left to right. At the end of the first
row, the row increments and the column address is reset to
the first column. Once the entire screen has been painted, the
refresh process begins again
�� The video signal must redraw the entire screen 60 times per
second to provide for motion in the image and to reduce
flicker: this period is called the refresh rate. Refresh rates
higher than 60 Hz are used in PC monitors
�� In 640 by 480-pixel mode, with a 60 Hz refresh rate, this is
approximately 40 ns per pixel. A 25 MHz clock has a period of
40 ns.

The vertical sync signal tells the monitor to start displaying a new
image or framme, and the monitor starts in the upper left corner
with pixel (0,0)
�� The horizontal sync signal tells the monitor to refresh another row
of 640 pixels
�� After 480 rows of pixels are refreshed with 480 horizontal sync
signals, a vertical sync signal resets the monitor to the upper left
corner and the process continues
�� During the time when pixel data is not being displayed and the
beam is returning to the left column to start another horizontal
scan, the RGB signals should all be set to black color (all zero)
�� In a PC graphics card, a dedicated memory location is used to
store the color value of every pixel in the display. This memory is
read out as the beam scanns across the screen to produce the
RGB signals

[/img]

 

[blueroomelectronics]

pic18f4525 with led matrix

640x480 is 307200 LEDs
Nobody is going to build that, the power requirements alone are enormous.
You could by a nice 42" PLASMA TV for less than the cost of the LEDs.
Most folks can barely get though an 8x8 display. The whole thread is pointless.

 

[xorcise]

you tube examples of full color rgb video led

The whole thread is pointless.

On this point, I am in full agreement. When the discussion of a large LED display digresses into a discussion of Horizontal and Vertical Sync, then these folks better stick to a TV picture tube, and try to better explain the duties of a microcontroller programmer with some IO to play with.

Notably, nobody is discussing even the simplest mono LED display and how to achieve different levels of "gray-scale" per dot. Something very important to any display that proposes to be anything resembling a decent picture.

That said, I leave everyone to this video:

Once you can explain how I do that (I've only met a few in these forums that can) then you might be a good candidate to upscale to a larger display.

There are some concepts that the majority will not understand... no matter how much explaining is done. This subject appears to be one of them.

Check out this very long thread if there is any doubt about that last point.
**broken link removed**

 

[manish12]

giant led screen forum

WHAT IS NEXT ?


PWM IS MORE COMPLEX FOR VIDEO , JUST THINK DIGITAL OUTPUT WE HAVE AND NEED TO CONTROL INTENSITY THEN OK , BUT HERE IS NOT A 1-2-3-4 LEDS , IT IS HUGE .

NOTE: PWM IS AN ALTERNATIVE IF YOU HAVE ONLY DIGITAL OUTPUT PIN .

NO NEED OF PWM , MAP THE RGB VIDEO SIGNAL INTO THE FULL RANGE OF LEDS VOLTAGE .

ANY QUS ? ON THIS ONLY ^

B+VE !

 

[blueroomelectronics]

led arabic japanes 5x7 array download

Problem is LEDs won't match in brightness from one to the next. And they're not necessarily linear in brightness. Feeding analogue voltage to each LED in a column will be very difficult compared to PWM.
Have you seen how complex a Plasma TV PCB is? It's enormous and packed with custom ICs.
If you want to continue talking theory fine, but this will never become a practical project.
PS large color displays are digital not analog.

 

[manish12]

how to make a full colour led display

-VE

 

[blueroomelectronics]

led scanning giant display project

-VE

Ok I give up, what does -VE mean?

 

[manish12]

640 480 led matrix

who say analog ?

it will be mixed digital + analog.

 

[Alan69]

i want to make a full colour led display

The whole thread is pointless.

On this point, I am in full agreement. When the discussion of a large LED display digresses into a discussion of Horizontal and Vertical Sync, then these folks better stick to a TV picture tube, and try to better explain the duties of a microcontroller programmer with some IO to play with.

Notably, nobody is discussing even the simplest mono LED display and how to achieve different levels of "gray-scale" per dot. Something very important to any display that proposes to be anything resembling a decent picture.

That said, I leave everyone to this video:

Once you can explain how I do that (I've only met a few in these forums that can) then you might be a good candidate to upscale to a larger display.

There are some concepts that the majority will not understand... no matter how much explaining is done. This subject appears to be one of them.

Hardly pointless, but seems most here lack a fuller vision. Almost posted the other day on the first page, only getting back on here now.

Of course there's a reason to use VGA to run even a smaller RGB display, access to all of the video and tools on a PC, and no having to program video into the RGB/controller, just make it a display.

How hard is it to think to use DVI instead of VGA, since it's digital and won't require analog or conversion? Set DVI down to 640x480 or lower so it's slow and easy to read. Wait for Vsync. Count 64 or 128 Hsyncs to have room for title bars etc, then start paying attention. Get the data for as many columns as you need then ignore until the next Hsync and get the next row. Background routine to run the display and do dimming etc. Use DDS methods to add to an accumulated total for each pixel and light on overflow, it's simply easier to follow than other PWM type methods and you just light on every overflow. Wouldn't be too hard to scale and match the colors/brightness between the R, G, and B either.

Picture quality doesn't matter squat for why it's worth doing this. For anything of any length it'll be vastly easier to make the animation on the PC and put the player in the right spot on the screen and play it back, even if it's only 8x8.


If you didn't see immediately to go DVI, setting it to lowest res for ease of getting the data, and the obvious utility of doing this, then you might not be as far ahead of the other guys as you're thinking. Popped right out on reading the first few messages of the thread.. But of course I was doing stuff like this when half here were probably still in diapers, running from a C-64 and similar in the early 80s, and running $20K LED signs in the mid 80s..

 

[marwan naboulsi]

led display canada

dear Alan69
did you have any data about how to use the dvi signals to drive a giant led panel
or can you share any data about dvi signals

 

[manish12]

single color color led using fpga-based

why , so hot topic it is ?

after , any new post / idea , all are just ready to fight !

be cool
i think from this fighting spirit , we have ability to make this Giant display .

:- this post is not a issue of fight , just for smile.

 

[jmaia]

led screen parallel plasma tv

I think this 2 documents may help understand how the displays works.

http://jsmaia.googlepages.com/Agilent-LEDmatrices.pdf

http://jsmaia.googlepages.com/ConsiderationsoftheDrivingElectronic.pdf

They help me a lot.
I'm now building a 40 x 40 LED display, 64 grayshades just to learn the basics. I'm using a STM32 at 72 MHz to receive from PC serial port, at 115200 bps, the data for the frames. Made a small Delphi program who decodes a AVI (reduced to monocrome 40x40 using VirtualDub) and send the data to MCU. It's becoming to work.
Best regards,
Maia

 

[xorcise]

make your own giant 7 segment display

Give that man some points! Great documents. Now maybe some of the commenters will stop and read instead of posting more nonsense.

 

[drbizzarow]

giant led screen

heheh welsaid

Added after 1 minutes:

im agree with xorcise comints