LED Sign with MMC Memory card

Author admin    Category All projects, Gadjet     Tags , , , , ,


At the beginning this project was to buy a led sign to interface with my home automation network. This automation network display information like temperature, wind speed, humidity, etc.  I had bought on EBay a LED Sign but when I received it I got a surprise! There was no serial port to program messages… After a couple of days, I look inside to see how it was built. 

The principle of operation is simple you have just 160 bits shift register with drivers for LEDs. I removed the old CPU from the LED sign and connected a couple of wires to the shift register (column driver) and the row driver to an ATMega128. The main reason why I chose to use an ATMega128 was the need of a large amount of RAM.  I decided to use a MMC memory card to store all the messages for 3 reasons: low cost, SPI interface and a lot of space for messages.


  • 3 Colors messages
  • 5 Scrolling speed
  • Serial port for uploading messages



MCU Schematic in PDF format

Board Schematic in PDF format

Source Code

41 Comments to “LED Sign with MMC Memory card”

  • engin July 15, 2010 at 1:22 pm

    for every tin tanks…   but have can we use this  projeckt whitout pc prgram ????

  • admin July 15, 2010 at 1:27 pm

    Yes you can it need only a terminal software

  • muhammet August 1, 2010 at 3:34 pm

    hi.ı have got a moving led sing.ı look your borad schematic and mcu schematıc.your schmatic board with my floating the same type of circuit.ı want to rebuilt my led sing with mmc atmega 128 reading directly the sourche code from mmc card? ı can not to upload the sing.c file to atmega 128.other source code is diffrent.what do work other source codes?

  • admin August 2, 2010 at 2:32 pm

    I don’t have any other source code, but the one you take on my blog work,

  • Djatie August 24, 2010 at 4:12 pm

    Does the data displayed on the LED matrix is taken from mmc?

  • admin August 29, 2010 at 12:52 am

    Yes in a text file

  • ercan November 4, 2010 at 2:59 pm

    Hi Sylvain
    hex file to an e-mail atmega chipset
    good work
    Ercan ADİL

  • chamli priyashan December 7, 2010 at 6:42 am

    hi friend
     is this moving sign realy werks??
    please reply me soon.
    thank you

  • admin December 7, 2010 at 2:05 pm

    Why it should not work?

  • akram akhgari February 23, 2011 at 11:05 pm

    Hello. Thanks for the information. How flash player (*.swf ) by mmc in micro loading. Please answer. Good luck.

  • admin February 24, 2011 at 12:45 am

    I don’t understand your question

  • akram akhgari February 26, 2011 at 5:33 pm

    hi  I Made an Animation by swish max  that its format is (.*swf) and I want to play it by led sign  with mmc card but I can not please help me . excuse me I AM Forein and I can,t speak english well . very tanks.

  • Resonance Cole March 2, 2011 at 11:21 am

    Hi yonder,
    Yes, I'm seriously enjoying all your projects. thanks to your Father. Well, I'm a complete novice to programming. really, I've being doing some projects on programming downloaded from the nets. but my problem is how to write the programs. Please, I want you to share few ideas with me. or if you can refer me to where to learn better.

  • admin March 2, 2011 at 12:56 pm


    First thanks for your good comments, For MCU programming you must begin at the beginning, make a led flash, make this led fast at the speed of a potentiometer, make a night rider, and so on you can’t build a MP3 player after one year of programming. it’s a long lurning curve.

    Good luck

  • Astina April 5, 2011 at 6:44 pm

    hi..      first, thanks for this project..
    I have some question…
    how many animation can present in this led sign (just like: scroll right to left, up to down or still text)..?
    how size memory card can use for this project..? 8MB, 16Mb or bigger…?
    thank you…

  • admin April 5, 2011 at 6:49 pm

    Only text, no annimation, there is no MMC PC compatible it’s only for the internal system

  • saba June 19, 2011 at 3:12 am

    can i program the display with keyboard

  • saba June 19, 2011 at 3:14 am

    can i program the display through computer key board

  • admin June 20, 2011 at 1:05 pm

    Yes via you PC with hyperterminal

  • Ercan ADİL July 8, 2011 at 9:10 am

    What is the hyperterminal values​​?

  • admin July 8, 2011 at 11:53 am

    I don’t remember it’s make to long time

  • admin July 8, 2011 at 11:54 am

    Study, read, try

  • Ercan ADİL July 8, 2011 at 12:13 pm

    c code to the web there m sorry

  • admin August 24, 2011 at 7:10 pm

    I’m so busy, I don’t have time to wrote application note, part list, and huge description of my work sorry


  • Sorin December 20, 2011 at 7:43 pm


    I want to build this project.
    Just must write in MMC memory card a text file "Hello world!" and will display it on Led sign?
    What is the name of text file? The name of file can be "test" and the text "Hello world!"
    Will works?

  • admin December 20, 2011 at 8:26 pm

    No there is not fat in this project the MMC driver is in the MCU code and it’s not compatible to anything


  • Sorin December 20, 2011 at 8:42 pm

    Thanks for quick answer.
    I mean after I will write the hex code on MCU, I will use a MMC where I have written a text file like test.txt with the text "Hello world!".
    Should be work like this?

  • Sylvain Bissonnette December 20, 2011 at 10:54 pm

    No it's not fat compatible  the MMC is only for the MCU read and write there is nothing to do with your PC

  • Sorin December 21, 2011 at 6:06 am

    I read above and understand that the MMC is written with a terminal software.
    This terminal software is separated? Where can I take this?

    Thanks a lot!

  • admin December 21, 2011 at 2:18 pm

    Hyper Terminal in windows

  • Sorin December 25, 2011 at 6:24 pm

    Merry Christmas and Happy New Year!!!

  • study February 20, 2012 at 11:05 am

    very good idea !!!!

  • Prasad May 4, 2012 at 9:45 am

    If i have two different hardwares 7×96 matrix and 7×128 matrix both fed with the same message, how the firmware knows where the message should end, and what matrix is used?

  • admin May 4, 2012 at 12:25 pm

    I don’t know

  • Paul June 9, 2012 at 11:40 am

    Exceptional Project.

    I have mono version of this board, this will help me a great deal.
    Thank you

  • saied October 2, 2012 at 6:23 am

    hello.thanks for your project, but when the conversion file mcu to the hex error

  • saied October 2, 2012 at 6:24 am

    hello.thanks for you project, but when the conversion file mcu to the hex error

  • admin October 2, 2012 at 12:22 pm

    What you meen by convertion?

  • saied October 2, 2012 at 2:02 pm

    for the programing,avr…………

  • admin October 2, 2012 at 2:15 pm

    I don't know why…

  • saied October 2, 2012 at 2:54 pm

    how to programing the avr 128

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Please note

All my source codes were taken from my personal projects.

Everything is for your information only. The C/C++ codes have been written
with ICCAVR. You can find the header and source CRT files by downloading their compiler.

All is for your information and everything is AS IS without any warranty of any kind. No other files are available and I don't make any modification for any body.



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