First Light on the Big Board

So I spent another week or so, and finally got all the power supplies mounted, power sequencer done, and everything connected up on the board so far. I made a power control/sequencer dealie so that I can turn the supplies on 2 at a time. This will prevent me popping the circuit breaker if I tried to turn all 16 on at once. The caps charging would suck a dip in the mains big enough to cause the lights to dim in the city I think. Other than that the pics are fairly self explainatory I think. Everything seems to be working and tomorrow I will mount the remaining 6 LED boards, and try it out on a full array. Note that the bottom LED boards show the data flipped. I thought I had set the bits in the controller but I guess I didn’t. There’s bits on the display signal streams that let my mirror the displayed data along X and Y, but I obviously didn’t set them, so the lower half is upside down. whoops.

Lots of holes have been drilled into the plywood “chassis”. The 64 holes for the supplies aren’t on there yet though.

All 16 supplies have been mounted to the board, woot.

Aaaand, here’s where all the nice new connectors I added poke through the front.

Closeup of the supply wiring connecting all the 120V stuff and what not.

These 8 relays sequence on one at a time to turn the two supplies on each.

First light with 4 boards!

Then some gameboy action

And now 6 boards.

9 thoughts on “First Light on the Big Board”

  1. Morning, Kev. This is looking great. Say, can you put a ruler or a hamburger or something in the next picture, to give a sense of scale? I’m gathering that this is… pretty big-ish!

    Can’t wait to see the pixel action.

  2. Hi, nice work.
    I have small problem in my boards. If I turn ON whole 16 LEDs on one MBI chip the average luminosity of LEDs dims. It looks like there is not enough power on board. But same effect in on the side og board with only 8 LEDs populated- if I turn on addition 8 “ghost” LEDs, the soldered 8 LED is light weaker. (PSU is OK)
    It very easy to detect the problem- just swith on 17 LEDs in row. The last, 17th, LED is much brighter than other 16.

    Do you have simmilar problems? Or just it is my FPGA code bug?

    And now about my boards: at last I reached some 262144 colors… ( Could you send info about RGB regulation rules?
    Or maybe you can send me some SOF file to test board?

  3. oh, I fixed the problem. I forgot the “white balance” PWM (using OE pins). It was runing at very fast speed. I didn’t change the design of this part from the begining, and in first experiments master clock was much slower. Now I reduced “white balance” clock and everything is fine. Now I need to check my “gamma” settings and the first stage of the project will be finished. (BTW I pusblished POF/SOF on my web page). I near future I’ll publish my source code. Iam interested to compare our codes. I would like to know how lame I am. 🙂

  4. Hi Kevin!

    Awesome stuff you’ve got there 🙂
    I’m wondering though, what’s the power draw like, per display ? Twelve supplies, that’s quite a lot of power you’ve got going there 😀
    There’s a bit of junk on the right-hand side of the GB’s buffer, wonder what that’s due to..

    Anyway, can’t wait to see the whole thing finished !

  5. Hi, can you tell me where did you bought this tricolor leds? And how much did you paid for them?

    Amazing project… Congratulations

  6. I was searching for information on the Gameboy Color LCD and I found your site. Those pictures show that you were displaying information from a Gameboy screen. How did you do that?

    Do you figure out what data is sent through the LCD ribbon cable? I would assume there are 12 lines for the color (4 bits for each Red, Green and Blue value), but I don’t know where they would be or what the other lines do.

    Do you have an LCD pinout you would be able to share with us? Do you know if the GBC screen has a Horizontal and Vertical Sync like VGA monitors do? I am trying to determine if it would be possible to wire the RGB bits from a GBC or GBA screen to an DAC (and resistors) to convert them to three 0 to .7V analog signals that could then be sent to a VGA monitor along with the Horizontal and Vertical Syncs.

    This page shows that a GBA has a Vertical Sync, but I am not sure if the Dot Clock would be the same as an Hsync or if the GBC would use a similar pinout. I guess if the dot clock sent a pulse for every horizontal pixel, you could build a counter to generate an Hsync pulse once every line.)

    It looks like you know a thing or two about electronics, so if this makes sense and you would be able to provide any more info on the Gameboy’s LCD, I would greatly appreciate if you could please post it here or email me.

  7. the gameboy LCD is pretty well marked with the signal names. There’s 8 bits of RGB each I think it was, or 7 bits of each. it was 1 more than you’d expect.

    There’s a pixel clock which clocks in a set of RGB, then a horizontal latch pulse which locks it into the row, then a vertical “next row” pulse, and finally a frame pulse.

    It won’t work on VGA without using a frame buffer to upconvert the video.

  8. I only opened up the back cover, but didn’t remove the circuit board, so that must be why I didn’t see any signal names marked near the LCD ribbon cable.

    I was under the impression that a computer monitor used the Hsync and Vsync to automatically display the color data across the screen (on your computer you can change your screen resolution to different numbers of pixels, and the screen automatically adjusts to fit it to the screen). My hope would be that the screen would automatically adjust the picture based on the syncs.

    Since a GBC has 160 horizontal pixels, at the 8MHz clock speed it would take the GBC screen 20 micro seconds to send the color data for a single row.
    At the VGA standard frequency of 25.175MHz, it would take 25.422 microseconds for a computer to send the color data of 640 horizontal pixels (640×480 resolution).

    With modern monitors being able to adjust the screen resolution, the time to send one row of pixel data doesn’t look that different between the GBC and the VGA standard.

    When you mentioned a frame buffer, were you referring to something that would stretch the Gameboy screen bits across a larger number of bits, and then output that higher resolution data to the monitor? Did you do something similar with your LED display?

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