LED matrix display - MD_Parola, MD_MAX72xx and MD_MAXPanel

Wow Marco,

what can I say "magnifico" What a great range of effects, I cannot think of anything else you might make them do but I am sure you will think of something. I had a look at your links but I must be missing something. Where can the control boards be purchased and where might there be information for connecting the switching controls and associated wiring,

thanks Pedro

Links for downloads lead here Pedro
https://code.google.com/p/parola-for-arduino/downloads/list

Thanks Crossroads. I saw the library file on the original link but not the board files.

Sharp as a tack today Pedro 8)

This now makes any 7219 projects that I try pale into insignificance

Thanks Pedro. I am sure that it could do a lot more but I have run out of interest at the moment and want to move on to something else. Maybe if others write effects they can be built into a future release ...

Documentation is included with the library in the docs folder as an html file.

Boards are not 'for sale' as such, but it is easy enough to use the SeedStudio files to have some made. It is actually quite cheap (about AUS$15 delivered to Australia) for 10 boards, so if you have not tried doing this before, give it a go. Takes about 2 weeks from order to postman delivering.

Thanks Marco,

you are too humble. I did not realise that you could get boards made so cheaply, so I will definitely order some and "start to a soldering" I have been having a go at a bit of toner transfer PCB making at home, but having some professionally made boards to work with would be great. Keep up the good work,

Pedro.

If you check e-bay, there are plenty of MAX7219 modules that have a chip, matrix, and input & output pins.
For example:
http://www.ebay.com/itm/1PCS-MAX7219-Dot-matrix-module-MCU-control-Display-module-DIY-kit-for-Arduino-/370827957354?pt=LH_DefaultDomain_0&hash=item565711946a

SMD versions too
http://www.ebay.com/itm/2x-Blue-8x8-LED-matrix-Max7219-Seamless-Cascadable-Arduino-PIC-Rasberry-Pi-MJKZZ-/390607543935?pt=LH_DefaultDomain_0&hash=item5af2061e7f

I did buy one of those larger units on eBay, as I started out wanting to use these 'off the shelf' type - they are pretty cheap. The problem (for me at least) is that the connections do not allow them to be joined up without cables. My design is similar but has connectors on the edges so the modules can be just plugged together.

The SMD units are more like where I would like to be at, but they are too expensive for my budget.

If one set of female headers is replaced with female right angle headers,
http://www.karlssonrobotics.com/cart/6-pin-right-angle-female-header/?gclid=CLyetIbV2LcCFYyY4Aodsj8AWQ
then adjacent boards can be plugged together.

If one set of female headers is replaced with female right angle headers,
http://www.karlssonrobotics.com/cart/6-pin-right-angle-female-header/?gclid=CLyetIbV2LcCFYyY4Aodsj8AWQ
then adjacent boards can be plugged together.

No doubt, but then with the joined units you have the matrix, the IC and then the next matrix. The matrices do not butt up against each other so, unless I am missing something, you can't build a continuous display (ie, matrix next to matrix next to matrix with no gaps).

Edit: for the sake of clarity I am not referring to the SMD units.

Very nice work. This is something I may look into using sometime.

marco_c:
Edit: for the sake of clarity I am not referring to the SMD units.

Where did you source your 8x8 matrices for use on your boards, and have you tried more than 10 connected?

Geoff

The section of the video showing 'Scrolling' has 12 units daisy chained and working together. That's all the boards I have made up to date. At this stage I don't expect to be building up the remaining 8 spare PCB (I had 2 lots of 10 made up), but I can't see any issues arising from having more of the units connected. Any specific reason you see 10 as a limit?

I get my 8x8 matrices from eBay. The last lot I bought were from http://www.ebay.com.au/itm/230754163950?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649.

The controller chips come from Tayda Electronics http://www.taydaelectronics.com. They are about $1.25 each, so are probably not 'genuine' but seem to work perfectly well. Here is an interesting article about that http://tronixstuff.wordpress.com/2013/05/16/the-max7219-led-display-controller-real-or-fake/. I also get my passive components from Tayda.

Thanks !

marco_c:
Any specific reason you see 10 as a limit?

No reason, I actually mis-counted the modules in the video :slight_smile:

Thanks!
Geoff

The web site has been updated with an additional PDF file documenting the hardware BoM, component sources, and assembly of the PCB.
https://parola.codeplex.com

Great job on the PDF Marco

Marco,

I have just completed populating eight of your boards and would just like to compliment you on your well written assembly documentation
+1 Buddha points from me 8)

Pedro

That's top feedback Pedro. It did look very comprehensive. I've ordered my components - going to tack 20 of these boards onto my next Seeed order :slight_smile:

Geoff

You will not be disappointed Geoff. I only have eight going at the moment but four more would be good. I am currently looking at the code examples to work out how to only use combinations of some of the functions. Great library.

Marco wanted to say thanks again. I've made up 20 of these and the result is lovely, and still plenty bright enough even powered from an Arduino. My intent is to make this into a self-contained display with an ATMega embedded in it. I have a small bug to work out yet - the 16th module from the left (regardless how I shuffle the modules) has several horizontal lines displayed. I'll do some more investigation on that.

Cheers ! Geoff

Thanks. I also got lines sometimes and what fixed mine was powering down the display (remove the connector) and then back on again, followed by an Arduino reset. To me it seems there is some timing issue on the reset at the start, as it appears to happen more frequently when many modules are used.