Hello from a very inexperienced builder

[Kaellis991]

Name is Kirk. Received my PPL SEL back in 1998 at the age of 45. Only flew rentals for fun. Now I am 67 without a medical and using X-plane to fill the void. So far, my cockpit is pretty basic, with 3 monitors, a touch screen with Air Manager and a Knobster, SLAW RX viper VT rudder pedals, Honeycomb yoke, the typical Saitek things (switch panel, throttle quadrants, trim wheel). Just recently added a Realsimgear GNS530 and thought I would complement that with a BendixKing KT76c Transponder built from a Arduino Mega 2560 controller. This is what I want to build but I am having difficulty trying to figure out the electronics.
https://cessna172sim.allanglen.com/docs/avionics/bendix-king-kt76c/
So since I am a complete novice when it comes to working with electronics and writing the programming I have been joining numerous websites to educate myself. It's not really going too well. I have seen lots of videos, and read lots of posts from X-plane, Arduino, SimVim, and many other ancillary websites. I am beginning to glean some knowldedge but I have a long way to go. I am hoping to get some good info from SimVimCockpit but after two days my registration there has still not been approved. So in searching for more and more information, for not only the basic questions but for what it will take for me to undertake what is beginning to look like a very daunting task, I stumbled upon this CB site. After a day of waiting for my registration to be approved I now have the ability to begin asking questions of you fine people.

[jackpilot]

Welcome aboard Kirk.
The whole Crew will help for sure.
Jack

[FredK]

Welcome Kirk

I believe you will find the people here very willing to help.

Specific questions generally work better than general questions. There are just so many facets to building a cockpit.  It is best to realize that this is a time-consuming project, but the journey getting there is for many of us the really fun part.  It all can seem very daunting at first...just stay focused by breaking down your project into manageable sub-tasks.  Rome was not built in a day...and neither was a home cockpit!

Fred K

Fred K

[Joe Lavery]

Welcome Kirk,

If you want to build a Garmin like the one in your post, have a look at Mobiflight. I believe it's a bit easier to start with and again there is a whole forum of very helpful people to help you get started.

https://www.mobiflight.com/en/index.html
https://www.mobiflight.com/forum.html

Joe.
 

[RayS]

As Joe mentioned, definitely go with MobiFlight. As you learn and expand your skillset, you may decide to go another route but offhand I can't recall anything comparable.

Firstly though (Thank you for allowing us to spend your money! :-) )

Pick yourself up one of these:

https://www.amazon.com/Display-MAX7219-Segment-Raspberry-Microcontrollers/dp/B07P5BNCCX

(Or 2... 3... )

Then search the interwebs for Arduino & MAX7219 Tutorials. Don't worry that some tutorials show a 8x8 dot-matrix display instead of the 7-seg display. the MAX7219 has 2 modes of operation.

Here's a good site to get you started:
https://tronixstuff.com/2013/10/11/tutorial-arduino-max7219-led-display-driver-ic/

However, word of caution: Start Simple. Get 1 switch to work on the Arduino.
https://www.arduino.cc/en/tutorial/switch

Then get 1 LED light to work (Don't forget the 330 ohm current-limiting resistor in series!)
https://learn.adafruit.com/adafruit-arduino-lesson-2-leds/blinking-the-led

I would suspect that this is how most all of us started out. Simple stuff first, then build on what you learn.

Welcome to the dark side!

[Kaellis991]

The avatars I am seeing with those awesome diy "cockpits" make me think I am in the wrong place. As much as I would love to do something like that I dont have the space, the money nor the time to build such immersive setups. All I want to do is build two items that I can mount on my desk.
The Garmin in that link is not what I am trying to build. That is way beyond my level. Purchasing a RealsimGear GNS530 is my level of expertise. But I would like to build the Bendix King transponder to mount just below that GNS530. I thought the transponder would be simple enough as a starter project. I already purchased the blue board 8 digit 7 segment display along with the mini switches shown in that transponder build. And I have already started down the Simvim route by installing the Simvim Cockpit firmware on the Mega 2560.
So I assume I cannot go with mobiflight on that board now.

I do have a raspberry 4 that is just running Ubuntu for now. Perhaps that can be utilized for Mobiflight?.
Thanks for the input...

[jskibo]

If it gets to be too much there's a guy selling GTX335 Transponder for 150 British pounds.  I bought a whole stack of his gear to go with my RSG GTN750.

[sagrada737]

Hello Kirk,

Congratulations on your decision to build a Sim!  This endeavor can be a long road no matter how you cut it, or how skilled you are in various areas.  The truth is, it can be a journey where every step is is frustrating and filled with difficulty, or it can be a journey that is filled with learning, fellowship, and the excitement of building something you can enjoy and be proud of to share with others.  But make no mistake, building a Sim is not a quick process.  As most folks here will tell you, it can take years to complete a full-scale Sim.

Since you have been open that your are new to Sim related electro/mechanical/software requirements, you should seriously consider what is "realistic" in terms of your capabilities and expectations.  As was recently suggested, you may want to plan a Sim building approach that does not require you to design and program modules for the aircraft you want to emulate in your Sim.

This brings up an important question...   What type of aircraft to you want to commit to for your Sim?  Once you commit to that, you can better define what paths are viable (realistic) for you to achieve your goal of building a Sim.  If you desire to build a General Aviation aircraft, then that dictates one approach.  If it is a airliner, then that will dictate a very different approach to your Sim project.  Each aircraft type will require different consideration.  If you go outside the mainstream, then you are asking for more customization in building your Sim.  Translate that into money, time, and complexity.

An analogy to Sim building is the dream of building a full-scale experimental aircraft.  There is lots of excitement at the beginning, but the building process can be daunting.  I know, as I have built both an experimental two-place helicopter kit, and a low-wing high performance jet turbo prop experimental aircraft (9 years to build).  Many people buy experimental aircraft kits, but never finish them due to shear magnitude of the project.   It is much the same building a full-scale Sim.  The point is, it takes a vision and a commitment in both time and money.  Most folks underestimate the amount of money it takes to build a full-scale Sim.   Likewise, most folks underestimate the amount of time it will require to build a full-scale Sim.  Thus, have a stated goal, and consider the "total cost", and plan your Sim project carefully.  Doing so will yield seasons of fun, learning, and rewards.  And if all goes well, you will someday have your own Sim.

As a side note...  I have been working on my Sim Project for about 5 years.  I can tell you that there were times when I wanted to toss it all in the dumpster and take up something else.  Same with the experimental aircraft that I have built.  But with determination and a stated goal, these kind of big projects can be managed to completion, and it's no different for a full-scale Sim Project.

As a side note...   Here is a photo of the Turbine Legend experimental aircraft that I built; my wife and I flying off the coast of California.  Top speed of 320 kts, with a 6,000 FPM climb rate.  A serious aircraft, but pure fun!  It required 9 years to build this aircraft, but boy was it worth it!

Have fun planning your Sim Project.  This Forum is packed with folks that are willing to comment/help.  Best Wishes.

Mike

[Kaellis991]

If it gets to be too much there's a guy selling GTX335 Transponder for 150 British pounds.  I bought a whole stack of his gear to go with my RSG GTN750.

My endeavor is not to build a full scale cockpit sim like so many of the people on this forum have done, or are doing.
All I want to do is to build one instrument...a transponder.
That's why I think I am on the wrong forum here.

But buying pre-manufactured items is always easier than building from scratch when you don't have the manufacturing skills. It's a tossup right now on which way to go. Learning something new and frustrating or just pulling out the credit card.

How would I contact this guy with the GTX transponder?

[Kaellis991]

Hello Kirk,

Congratulations on your decision to build a Sim!  This endeavor can be a long road no matter how you cut it, or how skilled you are in various areas.  The truth is, it can be a journey where every step is is frustrating and filled with difficulty, or it can be a journey that is filled with learning, fellowship, and the excitement of building something you can enjoy and be proud of to share with others.  But make no mistake, building a Sim is not a quick process.  As most folks here will tell you, it can take years to complete a full-scale Sim.

Since you have been open that your are new to Sim related electro/mechanical/software requirements, you should seriously consider what is "realistic" in terms of your capabilities and expectations.  As was recently suggested, you may want to plan a Sim building approach that does not require you to design and program modules for the aircraft you want to emulate in your Sim.

This brings up an important question...   What type of aircraft to you want to commit to for your Sim?  Once you commit to that, you can better define what paths are viable (realistic) for you to achieve your goal of building a Sim.  If you desire to build a General Aviation aircraft, then that dictates one approach.  If it is a airliner, then that will dictate a very different approach to your Sim project.  Each aircraft type will require different consideration.  If you go outside the mainstream, then you are asking for more customization in building your Sim.  Translate that into money, time, and complexity.

An analogy to Sim building is the dream of building a full-scale experimental aircraft.  There is lots of excitement at the beginning, but the building process can be daunting.  I know, as I have built both an experimental two-place helicopter kit, and a low-wing high performance jet turbo prop experimental aircraft (9 years to build).  Many people buy experimental aircraft kits, but never finish them due to shear magnitude of the project.   It is much the same building a full-scale Sim.  The point is, it takes a vision and a commitment in both time and money.  Most folks underestimate the amount of money it takes to build a full-scale Sim.   Likewise, most folks underestimate the amount of time it will require to build a full-scale Sim.  Thus, have a stated goal, and consider the "total cost", and plan your Sim project carefully.  Doing so will yield seasons of fun, learning, and rewards.  And if all goes well, you will someday have your own Sim.

As a side note...  I have been working on my Sim Project for about 5 years.  I can tell you that there were times when I wanted to toss it all in the dumpster and take up something else.  Same with the experimental aircraft that I have built.  But with determination and a stated goal, these kind of big projects can be managed to completion, and it's no different for a full-scale Sim Project.

As a side note...   Here is a photo of the Turbine Legend experimental aircraft that I built; my wife and I flying off the coast of California.  Top speed of 320 kts, with a 6,000 FPM climb rate.  A serious aircraft, but pure fun!  It required 9 years to build this aircraft, but boy was it worth it!

Have fun planning your Sim Project.  This Forum is packed with folks that are willing to comment/help.  Best Wishes.

Mike

Mike,

I always wanted to do the home built plane thing but circumstances and logistics prevented that. I know some people through a good friend of mine that are avid RV builders and flyers. I actually think it would be easier to build an RV10 or 12 than build this transponder. At least there are instructions available.

Kirk

[Joe Lavery]

Kirk,

Believe me creating the transponder is not that difficult. The fact that it's just 4 digits makes it easier than a radio. Also because the Cessna radio uses buttons not an encoder, you don't have so much configuring to do.
But I appreciate these first steps look daunting. What you need is another local builder to show you the way.

All the best, whatever you decide.
Joe.

[Kaellis991]

Kirk,

Believe me creating the transponder is not that difficult. The fact that it's just 4 digits makes it easier than a radio. Also because the Cessna radio uses buttons not an encoder, you don't have so much configuring to do.
But I appreciate these first steps look daunting. What you need is another local builder to show you the way.

All the best, whatever you decide.
Joe.

Much easier said than done...at this time relying on piecing together youtube videos.

[jskibo]

If it gets to be too much there's a guy selling GTX335 Transponder for 150 British pounds.  I bought a whole stack of his gear to go with my RSG GTN750.

My endeavor is not to build a full scale cockpit sim like so many of the people on this forum have done, or are doing.
All I want to do is to build one instrument...a transponder.
That's why I think I am on the wrong forum here.

But buying pre-manufactured items is always easier than building from scratch when you don't have the manufacturing skills. It's a tossup right now on which way to go. Learning something new and frustrating or just pulling out the credit card.

How would I contact this guy with the GTX transponder?

He originally posted a n some of the FB flights Sim groups.
https://www.facebook.com/richard.hulme.12

[ame]

Hello,

I am not surprised that you haven't found anything specific that will help you build what you want. I did the same look around about two years ago and it sounds like nothing has changed since then.

It seems that most cockpit builders are not programmers, and most programmers are not cockpit builders. Companies that sell stuff want you to buy into their 'system', and most of the private projects are undocumented, so they are hard to replicate.

I don't want to single out SimVim, but it's not open source, so it's no good (IMNSHO). My own projects are also half-baked, but I do have some good ideas (I think).

The KT76C that you linked to was based on ArdSimX, which is dead. If the builder hasn't published how to do it with SimVim (and you can't figure it out) then it's a non-starter.

Certainly, it's trivial to interface a 7-segment display and some switches, especially with the wide range and low price of all the modules and components we can buy these days. I'd estimate about $10 for the electronics for that unit.

If you want to build that KT76C then I'd suggest it's a great starting project. It's well-defined, definitely do-able, and simple enough to make a good learning experience to build upon. Fundamentally, it's a display and some switches: get data from sim, put on display, send button presses to sim, rinse, repeat.

Since you are starting from a position of little knowledge and experience it will take you a while, but, where do you want to start?

[sagrada737]

I now understand that all you want is the KT76 Transponder.

FlightIllusion has a nice KT76 type transponder that will fit your needs.  For 330 Euros plus their GSA-055 interface card, you are all set and ready to interface to your Sim.  The nice advantage to this approach is that the GSA-055 interface card will allow additional FlightIllusion instrument modules if you want to add them, eg. Attitude Indicator, etc.  All Plug & Play.

I use quite a few FlightIllusion instruments on my 737-800 Sim, and they have been very reliable.  Believe me...   You will spend more than 330 Euros in time and materials trying to "cook up" your own Transponder module.

Here is the link to FlightIllusion's KT76 Transponder:

https://www.flightillusion.com/product/bkav-atc-bendix-king-style-transponder/

Mike

[sagrada737]

Hello Kirk,

Here is a link to Propwash Simulation's KT-76 type Transponder.  It's a Plug & Play unit that is compatible with X-Plane, P3D, etc.  Priced at only $90. it's a no-brainer.

https://www.propwashsim.com/store/pws320-transponder

Mike

[Joe Lavery]

Now that's a bargain, particularly with an aluminium faceplate.
Even making it myself, it's price that you begin to think, why would I bother!

For me the cost of shipping (UK) would be a bit off putting, however it's a small unit so even that might be acceptable.

I wasn't aware of this company, one to watch out for. Way cheaper than Go-Flight as well.

[Kaellis991]

That propwash unit puts a whole new spin on this decision to build or not to build.

[jskibo]

The propwash stuff is cheaper.  They go on sale quite a bit too so you can save a few more if your patient.

They are much larger than a standard radio size.  They would look OK on their own, but not paired with a normal radio or GPS unit

Mounting them is an issue unless your panel is thin as the circuit board extends nearly to the mounting holes.  You need a mounting surface thin enough to slip between the circuit boards and the faceplate to use the mounting holes.

Buy some 90 degree usb cables.  The cable he provide as cheap as hell and the connector shell pops off with any tension on the cables.  They are also too long to use if a mounting surface is in the way.  All the radio modules use 2 USBs as well.

I had them for two months and quickly sold them.  Would not recommend at all

[jackpilot]

I had them for two months and quickly sold them.  Would not recommend at all

That's a statement
Can you say precisely why you would not recommend (beyond size and USB cables.)?

[jskibo]

I had them for two months and quickly sold them.  Would not recommend at all

That's a statement
Can you say precisely why you would not recommend (beyond size and USB cables.)?

Size is definitely the biggest issue for me.  It looked goofy when used with standard size panel radios and GPS's.

I will add, if you're just flying a desktop and are fine with GoFLight type gear, these are way less expensive and will probably suit you fine if you can get by a few other annoyances. 

They worked ok, but if I left the PC running they would sometimes drop out and no matter how you tried resetting the device (including removing the cable and reinstalling) it would require a reboot to re-acquire the radio. (Note here, all my USB's are set to never sleep in all settings including registry so that weasn't the issue)

I also found switching channels would require two knob clicks to get a single movement of frequency.  want to go 120 to 121, turn twice.  But other times it would go back to sensing one turn per channel without reason.

I think the best "value" panel he has is the one with the trim wheel, flaps and gear.  I think I paid $60 on sale and that's damn cheap for a trim wheel that works well (along with the other toys on that panel).  Size wouldn't be an issue as that is normally placed lower on the panel.  I would still have that except my PFC Cirrus II has trim already.

[jackpilot]

Thank you for the details. 

[ame]

Does nobody care that the simulated device looks like the real thing?

The Propwash offering looks nothing like a KT76C. The Flight Illusion version has two buttons missing.

The original diy link at least has the right number of buttons in the right place, but they should be white with black legends. Also, the rotary switch has 30 degree spacing but should be 45 degree spacing.

I understand that you might want to limit the number of segments on the display, but it wouldn't be too hard to implement them.

Here is a photo of a genuine item with all of the segments illuminated (switch is in test position):
https://afors.com/_r/images/user/originals/11843_5_IMG_0005.JPG

I can see why a sim manufacturer might want to make something generic, but I can't see why an individual would. For this particular unit it's going to be some effort to make something, so why not make it look right? For example, you have to cut a panel, so why not cut it to the original size? You have to cut holes for the switches, so why not space them the same as the original? Eyeballing it is ok I suppose, but it's the same amount of effort to do it right.

As I said, there is about $10 worth of electronics in this unit. And maybe $1 million in design, assembly, and programming. If you know nothing and want to learn then it's an ideal project. If you just want to buy something then go right ahead.

If the look of the diy version is ok then I'd build it with the max7219 display module, 11 pushbuttons, a 45 degree rotary switch, and an Arduino Nano.

The display would be hooked up to three Arduino pins, the pushbuttons hooked up to 11 pins, and the rotary switch hooked up with some resistors to a single analog pin. Then some serial interface code, or i2c, or Ethernet, to get data back and forth to the simulator. Simples.

Again, this is a great learning project, and it develops the skills needed for every single cockpit instrument:
Determine dimensions
Determine switches and indicators
Draw physical instrument
Fabricate instrument
Install electronics
Implement instrument control
Integrate with simulator

...or you could just buy something.

[Joe Lavery]

Ame,
I would agree with most of what you posted but the biggest obstacle for most self builders is the programming; which is why I tend to suggest Mobiflight.

As far as "Does nobody care that the simulated device looks like the real thing?" is concerned, not everyone has the skill or facilities to make their own parts.
I have a CNC, a 65 Watt laser, a Metal lathe and two 3D printers, so I can, (and have) fabricated just about everything sim related. I also have the necessary CAD and 3D design experience to do so.
Yet getting exact dimensions of a panel, or other part can be something of a long process. Most of us draw on the information that floats around our hobby, adding to the pool of knowledge as it becomes available.
Sadly manufacturers are not in the habit of providing exact dimensioned drawing, so it's sometimes a matter of scaling an image to extrapolate that data. So the accurate positioning of buttons or knobs, even their size can be a "best guess".
My latest 737 shell is a case in point, it's actually nothing like a real one. If you look at its dimensions and structural makeup, yet I'm perfectly happy with the result.

What I personally don't have however is the programming knowledge. While I can design a circuit for a com radio, get the PCB fabricated and build it, I rely on products like Mobiflight to make it operational. I did have a go at SIOC a few years back but found it cumbersome, and after using BASIC unstructured.

So finally my point in all this waffle is not everyone has these skills we might take for granted, or the tools, or even the mindset that insists these item must be exact replicas; bought or fabricated.
We are all individuals with different opinions, and a certain acceptance standard for the items we fabricate.

What's "simples" for you, might not be for someone else.

Just my 2 cents

[Kaellis991]

After thinking it over all day I have decided to build the transponder. So to that end I have been looking at a small CNC machine to cut and engrave those plates and buttons. I can use it for later projects.
Rather than the Bendix King I would actually prefer to try to duplicate the Appareo Stratus ESG
https://sarasotaavionics.com/avionics/stratus-esg
although without all the functionality. I just need the modes and the code entry to work. WIthout the rotary encoder to change modes perhaps a little simpler?
Many of the functions are for for ADSB out which is not really necessary in X plane or even FS 2020. Just as it is in many of the Xplane and FS aircraft those buttons would just be inop.
One good thing about duplicating this unit is that I have access to one that is installed in an Arrow II that I fly occasionally with a friend who is a co-owner. If I need to learn how to use the other functions I will just go on a Xcountry flight with him some day.

Also, I was considering looking at Mobiflight instead of Simvim so I posted the question on the MF website.

Pizman82 sent this response
<snip>The Problem will be the "0-7" Buttons. Hardware Compatible but Software is problematic here.
With XPUIPC it is not directly possible to set the Transponder to a value by "number buttons". XPUIPC ( same way like FSUIPC for P3D and FSX) just allow to increase or decrease the Transponder whole Value or the single diggits..... Thats why most aircrafts uses 4 ( 2 or 1) Encoder for this and not something like a keypad.

<snip> On first view i would say.... Hardware is compatible.... You can controll lots of Xplane stuff with MF..... But the transponder in THAT way is not possible!

So I assume that I will have to stay with Simvim to get the buttons to operate without a lot of programming.