MobiFlight Community Support

Hello guys,
I am new on the forum and I hope I'm on the correct section.
I'm trying to make an EFIS panel for the PMDG 737 and I'm having an issue with the selectors for minimums and QHN. I saw on many home built simulators that the value is changed via rotary encoder but this is not technically correct. On the real airplane the selectors are rotated clockwise (to increase) or ccw (to decrease) by a few degrees, then they return to center with being spring loaded (pretty much like the car's key when ignition is turned on). A quick turn by a few degrees and there's a small detent, the value changes up or down by one unit, if you overcome the detent and turn more the value changes by ten unit. If you hold the selector in the first or second detent the value will keep changing respectively one by one or ten by ten until released.

Now back on Mobiflight:
I'm using the PMDG 737 on FSX Steam Edition, everything is paid and updated to the latest version.
I don't really care about the 1 by 1 or 10 by 10 detents, I can get the value (ex. minimums) to increase or decrease by one at the push of a button, I was just wondering if there's a quick way to keep it going if the button is kept pressed and stop when it is released. It's not a big deal for the QNH because it will vary only of a few hpa so I can afford to rotate the selector a few times, but on the other one setting the MFRA for takeoff (around 1000ft above aerodrome elevation) and then reselect minimums for ILS (around 200ft AAL) will take like 800 presses of that switch
Unfortunately I am not a programmer and about Lua I've found out it exists only a few minutes ago looking for answers, so not a clue on how to even get started. If there's a simple way through the MobiFlight console of FSUIPC it would be awesome since I already googled and searched the forum for answers but I couldn't come up with anything yet.
Other than that software is great, easy to use and it gives a lot of possibility

Thanks in advance
Luca

Hi Luca,

I know on a 777 the baro knob has two noches each direction. First noche is slow increase/decrease next is for fast acceleration. The PMDG has this technique not implemented in the 737 software. My EFIS has encoders, so I had to chance in the options of the 777 the use of encoder. This possibility exist.
All in all with baro encoder all my PMDG planes are working, but with 737 it´s a mess. On higher airports you can begin short after start drive in the baro settings for landing, because without acceleration you need a long time to set. Sometimes I wished I had a motorized encoder. The problem is, PMDG inputs can not manipulate with offsets, so no acceleration can set. If you use baro with mouse in VC the problem is the same, to long time is need to set higher baro settings. 747 or 777 from PMDG are in this case much better then the 737.
I use in the 737 radar minimus for CAT 1 approaches - not real I know, but it helps me not going crazy.

737 has no EventId´s for slow and fast acceleration, so it´s no different if you use an encoder or switches. Maybe there exist some workarrounds with lua scripts, but I don´t know a solution for this problem.

Greetings
Gert

Hi Gert,
yeah I understood it's a bit of a mess looking in the forum and so on, so I dropped the idea of the two notches from the start, because although it would be the realistic one it's not a feasible option with my (low) level of skill in the software
So at this point I was just hoping for a workaround that consists in having a knob that, when turned either side, presses a switch which increases or decreases the value (I just bought a 3D printer and I'm working my way around the hardware, and tbh I'm having fun like a kid ), and if the switch is kept pressed the value keeps increasing until released. It doesn't really matter if there's no acceleration, I mean it would be great if there was a chance, but for the sake of simplicity I can drop this thing too. It would be just nice if I could have the short press to increase/decrease 1 by 1 and the long press for large variations. Do you think there's any way to achieve that? I saw this topic of a guy trying something similar but my experience in the software is not enough to properly understand what they're talking about (for reference the topic was called "Triple use of buttons in Mobiflight"). Another option will be doing with the encoders, since I could already make them work at least on the breadboard, but it wouldn't feel like the real one. I know it's a small thing but I would use this EFIS (and other panels I'd like to build in the future like the MCP) for training, since I'm rated and I fly as a first officer on the real 737 and it's great to refresh stuff you never get to do in the line like unusual approaches or emergency stuff before the sim sessions we have, so I was looking for something that was as close as possible to the real thing.
Unfortunately I haven't tried the 777 or the 747 by PMDG in years so I can't really tell what the differences are but as far as I understand from you I picked the harder plane to configure

Anyway, thanks a lot for your answer
Have a nice day
Luca

A switch you prefere it´s hard to find on the market, but you can build this by your own. You can use a normal 8 or 12 position rotated switch - easy to find and cheap. This switches have a manual stop pin, so you can limit the switch to 3 positions. Now you have to mount a spring to the axis, so that notch 1 and 3 snap back to notch 2 (neutral position). Then set positon 1 and 3 to baro EventID.
Maybe there will be a repeat problem with mobiflight. Normaly I don´t use mobiflight for inputs, so I can´t say if there is a possibility to repeat EventID´s. I use HID-Controller and assigning my buttons direct in FSUIPC. Repeat buttons are no problems there.
It should not be a big act to realize this funktion, it´s more a mechanical skill than an electical.

...since I'm rated and I fly as a first officer on the real 737...

That´s nice, so I can ask you if the rudder trimknop works in same way. Here I have also the possibility to use an encoder or a switch like above descripted.

Unfortunately I haven't tried the 777 or the 747 by PMDG in years so I can't really tell what the differences are but as far as I understand from you I picked the harder plane to configure

I think PMDG did this to manipulate the baro knob with mouse wheel. They don´t think to much about us "Real Knob Freaks".
The difference is only in 777 or 747 setting the baro altitude goes much quicker, whatever with encoder or buttons.

Greetings
Gert

Hi Guys

As Gemu said.... Mobiflight itself have no Repeater Support. ( In the early days Mobiflight was never planed to make Inputs.... so this feature never get implement )
Best solution here is FSUIPC itself....
If you already have a HID Controller ( Like LeoBodnar, UnoJoy etc) then you can simply set this "button" as a Joystickbutton Input.
In FSUIPC ( Registred Payware version ) you can now set to this Joybutton the needed PMDG Event and you make simply a Checkmark for "REPEAT".

Alternate is "VJOY" feature from Mobiflight.
You have to install VJoy Software..... Then you can assign a button Input in Mobiflight as a "VJoy Button" . Then its basicly like a virtual Joystick..... And That input is used in FSUIPC in same way like a real Joystick.

*****
About Speed.
Here PMDG is the problem..... Cause they not include the feature.
BUT In most elements a turning by Mousewheel for longer time or a bit faster speed ( More events are send in a short periode of time) i think that the change rate increase a bit.
Please get sure you use as Parameter for that Input the MOUSE WHEEL Values. If PMDG work simmular like in ALT, HDG and so on then a longer or bit faster turning should increase the LandingALT also a bit faster.

First of all thanks guys for the help, I'll try to answer in order!

A switch you prefere it´s hard to find on the market, but you can build this by your own.

Indeed, I thought about rotary switches as I already have a couple of 12 positions that I use for the Mode Selector and Map Range Selector, manually limited to 4 and 8 positions, but they are pretty hard to rotate, I'm scared a spring won't be able to handle it. Maybe I just got a stiff one, I don't know
So far my plan was to 3D print the knobs with a cam in the part behind the panel. That cam when turned will simply press a momentary switch on either side and will be kept in central position by a spring, but I might change my mind if I see it's too hard to achieve or just not worth the work

That´s nice, so I can ask you if the rudder trimknop works in same way. Here I have also the possibility to use an encoder or a switch like above descripted.

Yeah, rudder trim knob turns left or right (I think about 45° each side, but I'm not sure, I'll check in the actual plane in a couple of days) and it's spring loaded so it turns to center every time. There's no double detent here, and as far as I know the speed of the trim is fixed. For example when you need to adjust the rudder trim in flight with the A/P disengaged you just turn the knob for a second, see if the plane flies straight, and if not you keep doing quick adjustments, like one second each and letting the aircraft stabilize between the corrections until you're satisfied. With the autopilot engaged (you need to be in HDG SEL, even if it would work in LNAV as well, but the procedure tells you to be in HDG) if you see a control wheel displacement on one side give the same quick adjustments on the side of displacement until it get level again. Interesting note: it acts on the Rudder Feel and Centering unit, effectively resetting the neutral position of the rudder itself (so no balance tabs or stuff like that) and the pedals moves proportionately with the trimming (although the movement is really small, for example in the engine failure you want to trim about 4 units towards the operating engine, but you'll barely feel the pedal movement). This movement doesn't happen with Yaw Damper operation since the YD acts directly in the rudder Power Control Unit, bypassing the Feel and Centering Unit.
So to summarize, in your case if you want to keep it real go with the spring loaded switch instead of the encoder!
For any other questions just ask and I'll let you know

If you already have a HID Controller

No at the moment I'm just using an Arduino Mega, with normal switches and knobs from eBay, so as soon as I go back home in the weekend I'll try with VJOY as you suggested and let you know if it works! In the meantime can I ask you if once I get it I have to do everything with that or if I can still keep using Mobiflight in the traditional way and VJOY only for what I need? Thanks in advance but I don't have my PC with me and I can't try if before saturday

Anyway, thanks again for the answers guys, have a nice day!
Luca

...but they are pretty hard to rotate, I'm scared a spring won't be able to handle it...

Yes, that could be. I have this switches also for Mode and Range. The spring need to be stong to snap back. Inside the switch is ball and a coach spring. You can manipulate that to get a better feel. But I know, open this kind of switches will be a annoying fumble, so may it´s better to build that switch by your own. Your idea with a cam and two momentary microswitches could be the better solution.
I will go this way with the ruder trim, so I can realize this 45° each direction. Btw, thanks a lot for your detailed explanation. It´s great to have a professional here. Some things are hard to find out and we don´t want pay 500 bucks for a simulator hour just for looking how a switch works.

In the meantime can I ask you if once I get it I have to do everything with that or if I can still keep using Mobiflight in the traditional way and VJOY only for what I need?

There are many solutions in cockpit building. I use mobiflight for outputs and BU0836 controllers from leo bodnar for inputs. Not cheap, but worth every penny. Alone for analogue inputs I use 3 controllers (steering columne and throttle quadrant), so every controller give me 32 buttons extra. At the latest if you need analogue inputs you need a controller for that. By the moment VJoy will be a solution for your baro switch, but later an other problem will need an other solution. With mobiflight and BU0836 controllers I have for me the best mixture to realize most things in a cockpit. Stabil and easy to setup.
But as I said, there exist many ways to build things. Something to take notice. As the cockpit grow, things are getting complexer and may confuser, so it can be a good idea not mixing to much different solutions for every funktion. A good planing helps to save nervs and money.

Good Landings
Gert

Hi Gert,
first of all I wanted to point out that I checked on the real 737 and the rudder trim switch moves definitely less than 45° each direction, probably around 30°. In fact if you look there's a small arrow pointing inward on each side and the switch will move around half a centimeter past the arrow. Just to be a bit more precise
And as always, any question about the real thing... Just ask!

About the boards, I am still looking for some easy way to get started and for the moment the idea of building a whole cockpit looks quite ambitious to me, also because I spend in that phone box the best part of my working day, so if I also bring the job home people will really start thinking I'm crazy
Anyway, I will take into consideration to buy a dedicated board like the BU0836 to start making some experience on it, to be prepared on any crazy idea I might get

Have a nice afternoon guys! Thanks again for the answers

Hi Luca,

The BU0836 is a very good start if you want to experiment with analog values ​​that the potentiometers provide. Leo Bodnar would also be the first address for me.
Potentiometers with the value 10kOhm are most frequently used in this context. That seems to be the value that has been established in practice. Please make sure that the potentiometers are linear. The opposite would be logarithmic values ​​or scales, which are probably rather unsuitable.
The BU0836 also has the advantage that you can also work with switches there. You don't need a MobiFlight for these switches, you can assign them directly via FSUIPC. The 32 switches on the BU0836 are a switch matrix. Using these in a Sim can be problematic when two buttons are pressed at the same time. If you do not use the matrix, you can still use 12 switches individually for each BU0836, which can be defined directly via FSUIPC.

If you want to experiment with MobiFlight, you can use any MEGA 2560 R3, also as a clone. Simply define each possible device (switch, LED, stepper, MAX7219 etc) once on the board, then you are ready for all experiments and do not have to use existing configurations for it.

You are absolutely right to build a complete cockpit is quite ambitious. In addition to ambition, you also need the small change, especially since you would replicate your job, which would probably make additional demands. If people think you're crazy, leave them. They only document that they would like to, but do not dare to do that
Then the whole world is a madhouse and the headquarters would be with you. So what!?
You could also read comics or sort stamps. Crazy from the perspective of many people. Then we're all crazy. As long as it's fun - please

I think, unlike most of us, you have the opportunity to get original parts that are not available for the normal people among us (keyword: maintenance). With that you would be envious looks for sure

If you want to rebuild an EFIS or MCP for the PMDG B737, this should not be an obstacle that you cannot take. Compromises are required when it comes to the flashing characters in the IAS / MACH display. They cannot be reproduced with MF.

You will find that the more you experiment with the components, the more intense the desire to build something "tangible". Your understanding of the technology will also be intensified. Beware, it can become addictive

In any case, a warm welcome to this community!

Interesting question.....

You as a Pilot.... Do you looking for a Homecockpit that looks 100% Real OR do you enjoy just the real optics in your job and you need just a "Fun Simulator" to test some things.

the biggest Problem we all got here is to build a cockpit in the correct Optic.

For example some rotary switches in a real B737 have a 45° switching angle..... But the common 12 Pos Rotarys got just 30° angles. So for real optics we need to by verry expensive 45° Switches or working with Cogwheel-gears to reproduce a 45° with a cheap 30° Hardware.
Same with Panels. Building a Korry Switch with 2 individual Light Chambers is verry advanced or need extrem high investments for real Switches ( up to 80 $ each) .

So summary....

Building a Cockpit with all switches and gauges working is no big deal and already possible pretty sure for less then 500$ and without big knowledge..... But here switches look not real.... Are not on the correct Positions..... Display show needed Data but not in same Optic and Syntax like in real B737 and so on.
The high ammount of working time, knowledge and Monney still come if you try to increase real optics.

...and the rudder trim switch moves definitely less than 45° each direction, probably around 30°

Ok we go for 30°. In this case a rotation switch should be fit too. Due to the fat knob, the notch force is may negligible

Anyway, I will take into consideration to buy a dedicated board like the BU0836...

Take the BU0836X version. The matrix is onboard, so you don´t have have to solder a diode matrix. A terminal block is also onboard.

You don't need a MobiFlight for these switches, you can assign them directly via FSUIPC

.

BU0836 also supports various encoders. Witch is very comfortable.

Hi guys,
thanks for all the advices! So just to answer to pizman82 first and recap my intentions:

You as a Pilot.... Do you looking for a Homecockpit that looks 100% Real OR do you enjoy just the real optics in your job and you need just a "Fun Simulator" to test some things.

I am looking for something I can use for practicing the procedures and the maneuvers, especially in autopilot (that's why I wanted to build primarily the MCP, because the EFIS was just to get started and learn to use MobiFlight to be honest) because the PMDG won't give a real feeling on the flight controls unless using super complicated force feedback stuff that wouldn't do anyway, because tbh not even the €5 million full motion CAE simulators that the company uses for our checks can reproduce exactly how the aircraft behaves so there's no point even trying in my opinion
The only problem is that muscular memory is a thing and having stuff too different from what you're used to can become a problem, for instance probably some 90% of our airplanes has the Collins MCP, while a small portion uses the Honeywell one. I swear I have to think twice before making a selection on one of these because even the fact of having smaller switches than usual will trick you when you're doing things quickly while listen at the radios and figuring out if you're high or low on your profile This is also the reason why the Speed knob has a different shape from the other ones... After your fingers gets used to it you'll immediately tell if you're turning the speed knob when you were supposed to turn the heading one!! For this reason I would like to go with something as close to the real thing as possible, but in the limit of what I can build obviously. Since I have one of the company training centre a bit less than two hours driving from home it wouldn't be worth spending thousands of euros in hardware (like the CP Flight, which by the way looks great but it's too much money for what I need to do), but if I can manage to pull out something pretty similar, cheap, and have fun building it myself that would be just great. Then I don't exclude I will use it for fun to push the limits and to do stupid things we're not allowed to do in the line, but the PMDG doesn't have an OFDM so that's another story

Compromises are required when it comes to the flashing characters in the IAS / MACH display. They cannot be reproduced with MF.

This is for example one of the compromises I would take... I mean if it's not possible I'll just leave it and that's it!

For example some rotary switches in a real B737 have a 45° switching angle.....

And this is one of the things I hate about the 737, so many different hardwares, the overhead just looks like a mess compared to an Airbus or even more recent Boeings. Some of the stuff have good reasons to be different from each others, but some simply are the result of years of modifications and upgrades on a machine from the mid '60s.
By the way for my "project" I would just go with the cheap 30° rotary switches, since most of them aren't moved in flight anyway

About the BU0836 or other hardware, I'm pretty sure that if I'll be able to create an MCP with MobiFlight I won't stop there, so it will be an option for the future, either as an integration or as a total substitute! In the meantime, a quick clarification:

The 32 switches on the BU0836 are a switch matrix. Using these in a Sim can be problematic when two buttons are pressed at the same time.

so just to understand, if for example I want to build like a landing lights panel, would it be a problem to have multiple switches to ON, or would it be fine just as long as they're not pressed at the same time? I mean is the position of the switch that matters or the action of moving it?

Another quick question about the MCP... I was able to make the 7 segments LED tube work with the Heading display, the only problem is that the only format is 8 digit (which makes sense since it's the limit of what the 7219 can handle, so it would be a waste to make it with less digits), but in the real MCP dimensions they simply doesn't fit and I'd like to avoid different measurements or positions for the reasons stated above. The HDG and Course displays for example are only 3 digits. I guess at this point the only solution if I want to keep the dimensions would be to buy some 7219 and separately the 3 digit common cathode displays with the resistances and condenser and manually solder them together on a board, or is there a simpler solution? Could the BU0836 or something similar be of any help?

Ok we go for 30°. In this case a rotation switch should be fit too. Due to the fat knob, the notch force is may negligible

I agree it could be the best option, make sure you get a good spring to keep it centered and you're done!

Thanks again guys, I'll probably have more questions soon! In the meantime have a great weekend and I wish a nice Christmas to all of you!!

Hi Luca,

On the problem of the switch matrix:
A matrix has an advantage if only one switch or, better, button is actuated. Only then will you have an X and a Y line active. The moment you press two buttons, you have two X and Y coordinates of the matrix active. Which X then belongs to which Y and vice versa? What about 5 buttons pressed at the same time? What belongs to what? It gets confused, doesn't it?

The landing lights differ in three sections: Retractable, Fixed and RWY-Turnoff. Different switches are required for this. ON-OFF-ON should be used for the retractables (ON-OFF-ON is only the switch position, not the evaluation of the switch position: 1st ON: Retract, OFF: Extend, 2nd On: [Light] ON) during the fixed and RWY-Turnoff are simple ON-OFF-switches (Light ON - Light OFF). As far as I know there are newer versions of the B737 that no longer have retractables. However, the PMDG B737 NGX still has it. This means that a matrix would also no longer be possible here.

The switches in the cockpit are not buttons that are followed by electronics that memorize the keystroke, but rather switches that take on a state and then display it permanently so that the crew can see which state is present at any time.

So there is only the solution with individual switches and 9 lines (including taxi lights)
That should answer your question.

To the MCP:
For the MCP you need 6 displays, 3 x 3 digits (2 x CRS, 1 x HDG), 1 x 6 digits (IAS / MACH), 1 x 6 digits (ALT) and 1 x 6 digits (V / S).
The MAX7219 can control a total of 8 digits per PCB. The modules are only sold with 8 digits (2 x 4). Pay attention to the green PCBs when buying, because only they have the removable tubes.
The high flexibility that these MAX modules have is immediately noticeable in the price: less than 2 euros / module.

If you would like to see what is possible with the MAX modules, take a look at the two links below

https://flyingforfun.weebly.com/cessna-172-cockpit.html/#ThePanel
https://www.mobiflight.com/forum/topic/921.html?page=1

Admittedly, both have made their own PCBs and do not use the original modules.

The MAX modules also have the following advantage: you do not have to use all 8 digits. It is also possible to simply leave 1 digit permanently dark by not appearing in any configuration. You can read a lot about the MAX here in the forum, but you can also ask questions and they will be answered.
The 8 digits can also be split into 2 x 4 or 2 x 3 digits. You leave 1 digit free for separation. The advantage of the PCBs with the removable tubes is that the PCB and display can be accommodated separately in one housing.
You can also buy 3, 4, 5 and 6 tubes in any color and then insert them into your panels. The tubes only need to have a common cathode.
Then the modules can be linked. Up to 8 modules form a chain. That would be 64 digits. You can connect 4 of these to each MEGA chain, that would be 256 digits per mega, which only occupy 12 pins.
I converted 14 of these modules by exchanging the 2 x 4 for 1 x 5 per module. If necessary, I would be happy to send you the conversion instructions. Just send me an email to stephanho [at] t-online.de.

The BU0836 has nothing to do with MobiFlight because it has its own USB interface to Windows and is accordingly recognized by the simulator. In connection with FSUIPC you can assign both the axes and the switches in FSUIPC directly.

You see, the more you know, the more questions seek an answer. But success compensates you for everything. But who am I saying this to?

I see you got a lot of questions and you need some guidence.....

If you like we can start a personal conversation ( WhatsApp Call, Teamspeak, Teamviewer, Discord or so)
I can awnser your most segnificant questions and you can tell me so many things i want to ask a real pilot since years.

At the moment my work not allow lots of free time..... But in middle January and specialy in February i pretty sure got some days.
If you like send me a Email ( Use "LUCA Mobiflight" in Header to protect Spamcheck). to pizman@freenet.de

And this is one of the things I hate about the 737, so many different hardwares, the overhead just looks like a mess compared to an Airbus or even more recent Boeings.

Thats the way of cockpit design in earlier times. I have a good MIG-21 addon and I always see in my mind´s eye how the constructing engineer dumped a box full of instruments and switches inside the empty cockpit and where the components stucks, the technique staff mounted it exactly on this place.
In comparison to a Mig-21, a 737 has a very clearly arranged design. May in earlier days the consideration goes more in "it´s better to have a knob anywhere that don´t have it - with time pilots will remember where the damned knob is loitering around"

This means that a matrix would also no longer be possible here.

Why, Stephan? Or do you mean a matrix can´t be connected to Mobiflight? Yes, but you don´t need one there. I use BU0836 for most of my switches and ON-OFF-ON switches are working like they should. Never I had any bad influences between my switches. Why should there a problem with a BU0836 controller? An ON-OFF-ON switch is from electrical sight same as 2 ON-OFF switches in one housing. If a controller can´t handle a ON-OFF-ON switch, it couldn´t handle any latched switch.
If you open the BU0836 controller in windows you see one botton active and the other inactive. If you switch to the other ON it change to opposit - it works like assumed.
Or do I have an error in reasoning?