MobiFlight Community Support

Hi
I have managed to connect 5x 7 segment displays in a chain by removing D1 on the display module, no problem.
Have connected my displays to the arduino ports 48 DIN,50 CS,52 CLK, GND to GND and 5V to 5V.
No problems whatsoever.

However when I want to connect another chain of 8x 7 segment displays the same way as the first ones, that does not work.
Have connected them to port 40 DIN, 42 CS, 44 CLK, 5V to 5V and GND to GND.
They are correctly configured in the mobiflight software, I have checked everything 10 times at least by now.

When I connect the first display card and only that one. Only strange numbers appear on the display when I test it.
Have followed every connected line, there is nothing wrong here!!!

It is connected just as the first chain.

Is it possible to connect two chains of displays to one arduino card?
(I use arudino mega 2560)

Is it possible to connect like I have done on equal number or do you have to use other connectors?
I have tried most but not this, since there is no available manual for the arduino cards and how to configure this. And now I have been working on the problem for weeks without a solution.

What might be wrong here?

Do not suggest contacts bad solders etc, I have checked everything like that, there is nothing wrong anywhere with the connections, that is 100% sure!

What is the strange limit of these arduino boards?
This is my first project when I try to build my flightsim external panels but arudino to me is ONLY problems so far.
Hopefully someone can explain how to setup several cahins of displays to the arudino 2560 mega.

Thank you in advance!

Hi sebpil,

I have 2 chains installed with me. One with 8 and one with 6 boards. Everything works fine here.

If, as you say, weird characters appear on the first board while using the test button, something is wrong.
Please replace this 1st board against another from the chain. Check each one individually to see if they are ok. Then you check that with two, then with 3 etc
If possible, check it with a seperate MEGA

As long as the test does not work well, something is wrong. If you've already checked it x times, dismantle it all and rebuild it, but only after the board test was ok.

I know it's a stupid job, but from afar I can not recommend anything else.

Thank you stephan for your comment.

I just removed display control card one which was the problem. When I connected the arduino to all other in the chain, everything works fine.
Too sad I did not have a single display control card at home. Need to wait a few weeks before I get replacement cards. Already ordered 15pcs so it will not happen again.

Nice to know it is possible to have multiple chains on a single arudino board. Then that question is out of the way.

Anyone know where it is possible to buy 7219 7-segmemnt displays where the displays are not soldered to the control card?
I order mine from the other side of the world since I have not found anyone in Europe that can sell such 7 segment displays.
My displays are custom made and I use "extension cables" for the displays that are place on my panels and that works great. All 7 segment display control cards are mounted about 20cm below the panel itself since there is no chance to mount two such displays as one piece next to each other plus a button between them.

I do not know if it is possible to upload images here so I cannot show what I mean.

Search ebay.com for max7219 8-digit led display 7 segment

https://www.ebay.com/itm/8-Digit-LED-Display-MAX7219-7-Segment-Digital-Tube-For-Arduino-Raspberry-Pi-NEW/223018311385?hash=item33eced5ed9%3Am%3AmMrzb9ZB5KTPr4_h-m-OOhw&var=521826611719

https://www.ebay.com/itm/MAX7219-Red-Module-8-Digit-7-Segment-Digital-LED-Display-Tube-for-Arduino-MCU/181723525156?epid=1384019010&hash=item2a4f90f024:g:ZWcAAOSwPgxVNwO5

Always look for the green pcb's. Only they have the display on sockets
I only buy from suppliers in shenzhen. Since I have never had problems.

Yeah I know, I have red color displays from my supplier in Shenszen but the shipping options are terrible and takes forever. However now I ordered alot of these displays so I will have in stock and do not have to wait.
Shipping time from china is horrible when there is no options.

Thank you very much for the links!

Sometimes shipping costs are offered at $ 3. You can take that and the goods will be delivered much faster.
But it is only worth it for one article (even for larger quantities). Otherwise, shipping costs always apply per item.
With 10 articles, that means 10 x shipping costs - that's not worth it. The shipping costs will be specified later in the payment process. Then you can choose

Hello again,

Strange thing just happened. It seems like the computer was in the need of a restart after I connected the four more displays to the arduino card.
Even if the arduino was not connected to the computer when I connected the new displays, something in the software must tell the computer what the configuration of the arduino was at the last point.

Super strange.
Today when I started my computer and connected my panels everything worked without any problems.......and I do not understand a thing. Have not made any changes at all. Just started the computer and it worked as it should.....
Well a lot of strange thing happens obviously.