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Caspajack
Posts: 13
Hi all,

I did a search first, but I dont see anyone having this issue.

I'm doing some preliminary tests to see how I get on with MobiFlight, so I hooked up a couple of MAX7219 modules to a MEGA with a rotary encoder which has an integral switch.
It all works fine after a few teething troubles, due to my lack of knowledge but after about half an hour of leaving the thing running, the LED display switch off.
I only have to press the swapover button and they light up again and continu to work perfectly,

Has anyone else had this happen, or am I missing a control option somewhere?

I'm running P3D v4 with a registered FSUIPC.

Any advice would be gratefully recieved. :)

John.
2019-05-13 19:17
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StephanHo
From: EDDG, Germany
Posts: 1260
Supporter
Hi John,

welcome to MobiFlight!

The behavior that you describe is normal and does not need to worry you.
I also have this "problem", my displays turn off exactly after 15:06 min.
It's basically no problem, this is the energy-saving mode of the MAX7219-chip. It will become active if there is no change in the display for 15 minutes. This also applies to the displays of other chains.
So I have two MAX chains with once 8 and once 6 displays. After exactly 15:06 min, they turn dark.

Sebastian (the developer of MobiFlight) knows this and has installed a "refresh" in MobiFlight. But it does not work for you and me. The cause is unknown.

If you build a display that is constantly changing or that can be expected (less than 15 minutes), that does not happen.

Normally, e.g. by frequency change, DME changes or similar constantly values. This prevents this dark switching.

As I said, actually MobiFlight should prevent that. So far only I have this effect that it does not happen and you are now the second to report it.
The reason why it does not happen with us, is not known. Since I know the reason now, I can live with it and have designed my displays so that in flight a change is permanently displayed. As a result, my displays rarely go dark.

So you did not do anything wrong, but pointed out an effect that should not actually happen and obviously many other usern remains withheld ;)
Grüße,
Stephan
2019-05-13 22:14
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Thierry70
Posts: 15
Good evening.
I use a Max 7219 without any problem for my squawk, but I have a similar problem with my two LCD screens (2004 and 1604) which use an i2c chip, the backlight of the screens is switched off after 15 minutes even if the display is updated (1602 displays a chronometer) and the lighting is controlled by an encoder Driving a relay ky-019. When the screens go out, I see in Mobiflight that the signal of the relay that operates them is still at 1.
Do you know if there is a known problem of the same type with I2C ?
Friendly
Thierry
2019-05-14 17:52
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Caspajack
Posts: 13
Many Thanks Stephan,

It's good to know that I did nothing wrong, and like yourself, now I 'm aware of the issue I'll just consider it a method of prolonging the life of the LEDs. :thumbup:
As I said, simply changing the frequency or even just swapping the active for the standby does the trick,

And thank you for the warm welcome, I'm sure I'll have more questions as time goes on.

The built in setting are brilliant, yet I struggle with the settings required when you have to fill in all the data yourself.
I had a go trying to settup a DME distance and Time to go... but failed miserably B) I can look up the FSUIPC offsets but the rest of the settings are a foreign language to me.

I'll read some more and see if these old eyes can make some sense of it all.

Best to you.
John.
2019-05-15 23:13
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StephanHo
From: EDDG, Germany
Posts: 1260
Supporter
Hi John,

only courage. Two years ago, I also had those old eyes, like you. Only now are they two years older and I see more clearly than before.
The more you engage with MobiFlight, the more questions will crop up. But there will be more and more answers by yourself.
The questions that you can not answer for yourself, you should not be afraid to ask here in the forum. Stupid questions do not exist, only dumb answers ;)

To your problem DME / time. For this we need to know which simulator (P3D V ?, X-Plane, FSX) you are using and which aircraft (standard, PMDG or similar).
Then let us work out the result and your eyes will shine. The best motivation to continue ;)

When you first start, you will have a container full of questions. Importance is a little background in electronics, data types and logical understanding. The container will eventually be empty and you can build your home cockpit in there.

@ Thierry: No, unfortunately I'm not aware that there is this problem with the IIC interface. I inform myself but once.
Grüße,
Stephan
2019-05-16 00:08
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Caspajack
Posts: 13
Hi Stephan,

It's comforting to know Im not on my own.

I'm using P3Dv4 at the moment with the very nice Just Flight Archer.

I know what you mean about the information overload. I remember when I was negociating the PPL exams (many years ago); and on one partciularly busy day my instructor said ,"if I asked you your name right now you wouldn't have a clue!". Yet a few months later it all became (almost!!!) automatic.

I've dabbled a bit with electronics over the years, so I know how to solder quit well and I understand the difference between a resistor and a capacitor, bur circuit design is a bit beyond me I'm afraid. I've done some back lighting with LEDs, in fact I built a small GA panale with goflight stuff and some freeware guages. But I'd like to use the arduino and Mobiflight to make my own guages and radio equipment.
I have a small CNC machine and a 50 watt laser, which I've had for some time, I use it for other things. But I have done some drawings for new panels etc.

It's the electronics where I fall down.
Still I'm willing to learn.

I like the analogy of the container by the way :thumbup:
All the best
John.
2019-05-16 15:27
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StephanHo
From: EDDG, Germany
Posts: 1260
Supporter
Hi John,

As I see it, you already have very good conditions for the project.
If you know the difference between a resistor and a capacitor, and have already worked with LEDs, then you can look optimistically into the future.

With your knowledge of CNC and laser, you already have many things in advance. You do not have to worry about electronics. MobiFlight is not about when which atom turns right or left. It's just about logic and not about programming. That's the beauty of MobiFlight.

And if there is the will to learn, then we can give the thirsty plenty to drink ;)
Grüße,
Stephan
2019-05-16 16:58
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Caspajack
Posts: 13
Hi Stephan,

You'll be pleased to know I've managed to get the DME and Kt working on a single module... Hooray...
But when I attach a second module, all the LEDs light up on the second module. that's even if Mobiflight is nor running.
I connected them with jumper wires from the same pin to pin, I assume that's right.

Any thoughts?

Regards
John
2019-05-19 18:22
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StephanHo
From: EDDG, Germany
Posts: 1260
Supporter
Hi John,

when you first define the LED display as MF-device you set it to one MAX-device. Did you switch it to two and resave the devices to the MEGA?
You know that you can daisy-chain up to 8 MAX boards)? If you don't change this setup to the number of devices you connect in a chain the chain can not work.

Next is the diode D1 on every board. It's a protection diode in the case you congound + and -. If you also chain the +5V wirde from board to board the 3rd one won't work because every diode drops 0,7V. So the 1st board runs wit 4.3V, 2nd with 3.6V and the 3rd only with 2.9V. The min. Voltage for save operation is 3.4V.
You can remove the diode an wire bridge it on every board or you wire each board separately with 5V.

You can install max 4 daisy-chains with 8 MAX-boards each per MEGA. That are 64 Digits of 7-Segments in each chain. If you do so please use a separate power supply.
Grüße,
Stephan
2019-05-19 22:57
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Caspajack
Posts: 13
Well thanks to your pointers Stephan. I now have most of the items I need working fine.

Although the 8 digit boards are not always suitable where a six digit option would be better.
I see that one of the moderators suggested removing the LED modules from the board and re soldering 3 digit LEDs.
However that would need fully compatible LED modules, and I have been unable to find ones that match.
In addition some of the latest MAX based boards have LED's soldered directly to the board.

However as you suggested I have learnt a lot by watching and reading, then trying it out to see if I've understood. :-)

Regards
John
2019-05-23 11:23
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pizman82
Moderator
From: ETSI, Germany
Posts: 2464
Supporter
In case this is explaned 1000 times ( use Forum search for "max7219" ) i will use just short words.....

1. Removeable Diggits.
There exist 2 Types of Max "TUBE" Modules... Soldered and removevable. Mostly the soldered are with Blue PCB the other got Green.
Simply order the Rmoveable always .... Like this... https://www.amazon.de/8-Digit-Display-MAX7219-Digital-Control/dp/B00P9277BE

2. Correct Display.
There exist no alternate Display Block ( like 3 Diggit or 5 Diggit) that can fit directly on the empty Pins if you remove the 4 Diggit Block.
Simply cause 12 Pins are designed for 4 Diggits.
If you use a other Display you normaly must ALWAYS rewire the logic.... Means you NOT connect the Display directly to the Pin Connectors.... You must wire the Lines ( 13 single wires for example on a 5 diggit Display) Most users do that with "precission dupont connectors" or simply solder that.

3. Perfect way.
Professional cockpit Builders design there Elements with a self Build PCB. In That case nost users work with "Single 1 Diggit" Displays. So you buy just 100 Diggits and you can build 3,4,5,6 Diggit Displays as you need. Here every Diggit need 8 Wires.... But thats no problem cause you design already the "lines" on the PCB ... So no cables are needed finaly.
Another benefit is that here the users will also include the raw Max7219 Chip on the PCB or they make a "connector" where you can connect the empty Tube directly... Then there are 24 Pins... Same designed like the tube and you just fit the tube on it instead to the Displays....

****
Summary:
Target is that your displays are NOT Mounted on the Tube.... The Displays ( with diggitnumber of your choise) are mounted in the Panel and are connected (wire or PCB Line) to the Maxchip that is on another spot in your Cockpit. With that technic you not must design "space" behind the displays to also set the tube there.
Good Luck !
2019-05-23 14:32
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Caspajack
Posts: 13
Many thanks pizman82 for your concise and swift explanation,

I apologise if I'm asking questions posed by others before, I will try to make more use of the search facility before posting.

I have produced very simple PCBs before, manufactured in China, they are so cheap it's not worth the time wiring by hand. So I will see if I can design what I'm going to need.
I've downloaded a pinout of the MAX7219 so I will get some LEDs to incorporate the design if possible on a single board, we'll see how I get on.

Thanks again
John
2019-05-23 19:41
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