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Topic: Scrolling LED matrix display - Parola for Arduino (Read 85012 times) previous topic - next topic


I just built eight of these modules with parts from ElectroDragon and it is easily the most satisfying Arduino project I've ever built.
All I needed to do was change the message in the demo and the number of displays. The code compiled without error and worked at first go. The Electrodragon boards were modified slightly from the original to use wider traces for power and ground and data between modules. The supplied artwork can go directly to SeeedStudios for manufacture and the total cost was less than $30.00 for all eight of the modules I built... Wow, I got Blinken Lites...

--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard


Great stuff.  Of course I'll have Popcorn playing on tight rotation on brain-FM now for the rest of the afternoon after your video :)

That song is a tango, believe it or not. At least I've heard it used as one.


Some basic questions:

1) How big are the displays? (I mean in millimeters)
2) At what frequency do the displays flicker? From what I understand, all such displays do flicker; it's just a question of at what rate. If the rate is poorly chosen, the display will be annoying if not painful to look at.
3) How would I go about changing the font?

Note: if the digits are not all the same width, then if you have a clock showing seconds, the numerals will jump around on you.


Dec 01, 2013, 11:18 am Last Edit: Dec 01, 2013, 11:28 am by marco_c Reason: 1
1. The display matrix is about 1.2" square
2. The MAX7219 datasheet says the refresh is minimum 500 Hz, typical 800 Hz. Animation speed depends on what the program does but it can run faster than you can read, for sure. These are definitely not painful on the eyes.
3. Font file is in the library as data. Easy to change if you want to. If you do, send me a copy and it can be included in the main library.

Proportional and fixed width fonts are included. Text messages work best as proportional. Things like the time need a fixed font. The numerals only jump if you want them to.
Arduino Libraries http://arduinocode.codeplex.com
Parola for Arduino http://parola.codeplex.com


Dec 04, 2013, 03:04 am Last Edit: Dec 04, 2013, 04:28 am by Pedro147 Reason: 1
I was so impressed with Marco's Parola for Arduino project that I have, with Crossroads invaluable help, designed a PCB that uses the larger 60 mm square LED matrices. Here is the thread where this is developed and once I have done some minor tidying up of the Eagle package Marco has kindly allowed me to put the files up on his Parola site for download. The final version of the Eagle files in reply # 28 of that thread are functional aside from the fact that the drill hole size for the sixteen LED matrix holes are marginally too small. This, along with some other minor cleaning up will be done before they are put up on the Parola site.


Great work Pedro.

Now we have Mama Parola and Baby Parola. Who will do a Papa Parola? I am expecting window size :-)

Arduino Libraries http://arduinocode.codeplex.com
Parola for Arduino http://parola.codeplex.com


How much to buy the things already assembled? Or at least with a circuit board already printed; I haven't the facilities for printing them.

Also, is there any intermediate size of matrix (maybe 40 or 50 millimeters) available?


check e-bay, several sizes are available. May not have the nice, neat interconnections, you'll have to take care of that.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.


got link to download this MD_MAX72xx.h ?  :)


got link to download this MD_MAX72xx.h ?  :)

It's a little tough to find on the CodePlex site but here's the link:




Dec 12, 2013, 01:27 am Last Edit: Jan 31, 2015, 12:53 am by Pedro147 Reason: hperlink
Marco has kindly allowed me to host my files for the Bigger Arduino V1 on his CodePlex site here


The Eagle schematic and board files, seeedstudio gerbers and custom 8 x 8 LED matrix are all included.



Dec 14, 2013, 05:57 am Last Edit: Jan 31, 2015, 12:54 am by Pedro147 Reason: hyperlink
I still have a bit more work to go but these "Mama Parola" 60 mm displays are looking good  :D



Looks good Pedro - get a tripod for that camera tho & fire the cameraman :)
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.


Dec 14, 2013, 07:40 am Last Edit: Jan 31, 2015, 12:55 am by Pedro147 Reason: smiley
Too true Crossroads,
I have been meaning to fire that guy for ages   8)  And that was after a bit of Youtube video stabilisation too. I will have to shout myself a tripod for Christmas, which reminds me, all the best to you and your family for the festive season and stay safe,

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