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VR-FlightSim
From: United Kingdom
Posts: 97
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Hey guys
Still working on my PA23 250 simulator. Almost all of the original instruments have now been converted to work with mobiflight but it came to the point where I can not figure out how to proceed next. I'm talking about RMI as well as HSI actually.
The thing is, these instruments like the RMI have three individual axes that will be driven by three individual steppers (compass card, ADF needle, VOR needle).
The problem is, when MF turns the compass card servo, we need to turn the other two with it, maintaining their respective position to the compass card.
Does anyone have any idea how to crack this one?

Also on the side note, is there any chance we could drive simple two pin electromagnetic 5v gauges like Cessna style fuel indicator directly from Arduino?

Many thanks for your help.
Kind regards
Jay
2019-06-30 20:00
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pizman82
Moderator
From: ETSI, Germany
Posts: 3522
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Anout the 5v magnetic stuff....
Here Stephan is your Pro i think.
(Whatever this sounds as a analog controll like a servo.... isn´t it ?? )

About the Offsets....

In case i looking for B737 i not already work with those analog Displays.... And as you said.... The problem is you like to implement a System that use "maby" other technics.
But basicly we always can think about a solution.

System:
Mobiflight get (A.t.m.) one big disadvantage .... It is not be possible to "combine" multiple values in a calculation....
We can use Preconditions like "Only work if Other Offset = X" BUT we can at the moment NOT change a value with formula in case of a other Offset Value....
So like you say Value should be the current Value ($) but minus the Value of Config B ( Config A 100° Config B 20° ) So our Output Result should be (100-20=80 )
In the future i hope Sebastian give us the "Variable Tool" so we can use Multiple Values in a Transform Line.... In That Case Transform look like $-"VariableB"

Aslong this is not Possible we have only 2 Options....

1. We work with fixed Values that are available in FSUIPC
OR
2. We manipulate a Value as we need it INSIDE Fsuipc with a Lua Script and use the self Build Value ( Supported on Free Offset) in Mobiflight finaly.

****************

About YOUR Situation.
I not see your gauge.... I Not know what exactly it should do ( cause i not work with analog Radio Navigation till now). In Case i also not have your AddOn its hard for me to figure out that completly.
Basicly we must know what data you need and how your gauge work ..... THEN we can check if Data is somewhere readable..... If yes fine.... If Not you must think about a script or wait till we get hopefully the tool in future.

My first catch for you is.....
iconQuote:

0C56 2 NAV1: relative bearing to VOR1, in degrees (0–359)


Check this... For the RMI this maby already work.

iconQuote:

0C6A 2 ADF1: relative bearing to NDB ( *360/65536 for degrees, –ve
left, +ve right)


Here maby a compare is needed if i understand correct that this offset is +180 to -180 Check out.

For the HSI i must see the Gauge and the mechanical logic first !
Good Luck !
2019-07-01 09:44
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StephanHo
From: EDDG, Germany
Posts: 1523
Supporter
Hi Jay,

do you mean that the gauges have only two pins (+ and -)? Are they voltage driven? Then there you need an analog interface. 0V is i.e. empty and 5V full?
Please be so kind and explain it a bit or publish a link to these items.
Grüße,
Stephan
2019-07-01 12:01
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VR-FlightSim
From: United Kingdom
Posts: 97
Supporter
Thanks guys, I'll try to explain a little better what's going on.
As I mentioned earlier there are few navigational instruments that fall into this subject.
RMI is just one example. The link below shows a picture of an identical instrument that I'm trying to convert. It is a typical RMI though.

https://drive.google.com/file/d/1lsfmbTIRo_pkcxHG0JEMz0xlhZ9I3vFI/view?usp=sharing

You see there are three moving components. Compass card, ADF pointer and VOR Pointer.
Now the compass card always turns towards current aircrafts magnetic heading. When it does that, the two pointers turn with it however they are pointing to a specific direction to which they are tuned to.
The picture example shows aircraft heading North and the ADF tuned to let's say NDB station which lies 10 degrees to the right.
If we turn the aircraft to the east the compass card will also turn to indicate 90 degrees heading and both pointers will turn with it like they were glued to the compass card. However, if we tune ADF radio to a different station, these pointers will swing to the direction of the new station (if it's in range).

So, in conclusion, your suggestion was actually very good. As these three components will be driven by three independent steppers, we would need some kind of interaction between the three.
The formula could be like FSUIPC's ADF value minus current Heading = true ADF value send to the stepper (thinking simple 0-359 range).

That means we need something like a sub-condition that will consider another offset (HDG) before reacting to its own (ADF).

I hope it makes more sense now

Regarding the electromagnetic gauges, I will start a new thread for those so we keep this one "clean" and on the subject.

Kind regards
Jay
[Last edited by VR-FlightSim, 2019-07-01 14:43]
2019-07-01 14:27
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pizman82
Moderator
From: ETSI, Germany
Posts: 3522
Supporter
As i said..... The Question is..... What do the offsets show us....

In that case you need....
1. Magentic heading..... To controll the "Compass" Layer.
2. You need VOR1 Direction from current point of view.
3. You need NDB1 Direction also from current point of view.

I not test it anymore till now.... so i can´t tell you how the offsets i recommend above are work.

so Simply test this youreself ..... Not use a Motor for this or a difficult gauge. simply connect a Mega Board of your choice ( Whatever no devices are set) just to allow Mobiflight to work.
Then make a NEW config and create a couple of Configs Lines in the OUTPUT section.

Read ALL Stuff you think that can be helpfully like the Offsets i said..... Maby others..... All that sounds like " Course/Heading Nav1 etc".
Then Run Mobiflight.... run Sim ..... Go into a cessna C172 and set a VOR (Nav1) in Range..... so you have a working Radio Navigation.
And NOW press "y" key and start "moving" ( I use keys 1/3 on Numpad) OR simply maka a flight with lots of 360° turns !
Now Observe what happens in Cockpit Virtual Gauge.... And observe the Offsets.
Find out if a Offset support you exactly what you need !

Result:
If you are lucky you find for example a Offset that show the Position not in relation to the Magnetic north.... Maby (If i understand Offset correct) it show position in 0-359° in relation to current heading......

Example .... If you have Heading EAST 090 and the VOR is exactly right then its at 180° SOUTH ...... BUT from your current spot it is just 90° Right of you.
If offset show VOR Direction in relation to Mag North then it have a value of "180" ......
If it show Direction in relation to Aircraft Heading then it is "90"

If you now turn a full circle the first offset will nearly stay constant at 180° but the secoond will run all the way cause VOR in relation to View change while a circle by 360°


YOU will need the SECOND one. ( So please try my 2 recommendations if those offsets still show what you need)

************************

Summary.....

ONLY if you not find a Offset that do what you need then you must think about a improvisional solution.... Here Your right.... If you just get the Magnetic Direction of the Nav1 and NOT the "relativ" position to Aircraft THEN you need a calculation with current heading to have a working Value for the VOR Needle Stepper !

In THAT case as i said Mobiflight will not help you and you need a script in LUA ( At the moment)
Good Luck !
2019-07-01 15:54
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pizman82
Moderator
From: ETSI, Germany
Posts: 3522
Supporter
UPDATE:

I just do it...You see in timeframe this takes me less then 15 minutes ( include search a old mega in my garage)

Both Offset work !

The NAV 1 Offset show you the position of VOR1 Needle ( Not related to Magnetic situation... Just to aircraft)
The NDB do the same.... whatever here Offset is -180 to +179 AND it need a Transform ( $*360/65536) as expaned in the List .
To get the NDB working for Stepper you need also a compare IF Value less then Zero <0 THEN $+360 ELSE $

NOW you have the magnetic Course ( For the Outer Shaft that turn the Compass Layer)
And you have 2 Offsets for the wto needles that work as the should (i think)
Good Luck !
2019-07-01 16:11
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VR-FlightSim
From: United Kingdom
Posts: 97
Supporter
:blush: I feel like a total idiot now...
I actually hooked up another stepper and tried it too right after my last post.
You're right, these two offsets work great.
For some reason I imagined that the values will be related to the North but they are indeed relative to the aircraft heading.

Sorry for all that confusion boys
and thank you for your help.
Jay
2019-07-01 16:37
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pizman82
Moderator
From: ETSI, Germany
Posts: 3522
Supporter
No Prob....

Lets wait until you build the other Instrument.... Hopefully it work also..... If not just request what you need. then we can figure out !

Regulary all important things are still available in FSUIPC..... But sure. I already found things that not be readable and those calcualtions are needed.
So not scare about to ask us again for help if needed.
Good Luck !
2019-07-01 16:57
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