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Project45 UNS1 Replica Development

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(Original thread started on 05-17-17 by Ron Rollo)

I have been working hard on a UNS1 CDU prototype to possibly replace the real CDU solution that we are using if the demand ever gets to that point. I got hooked on this quest when Eric found a CDU prototype that Will Sasse made a few years ago. That and Jason Hite saying, "It should be easy if you can make the RMUs as well as you have." So long story short, I have been looking into the possibility of designing and building our own CDU replicas.


With that said, please keep in mind that as long as the demand for the CDUs stays under control, the need for a replica CDU may never materialize. But if nothing else, we have the preliminary work complete to move forward.


The plan as of this moment is to build two or three working prototypes. They will not look pretty but they will be fully functional and replicate the real CDU identically, right down to the same pin outs. This way our current solution to implement the real CDU using a Arduino Nano interface card will be exactly the same with this replica CDU. This way Jason only has to design one code, not two or three for different CDUs.


This replica CDU is designed to use 12 volt LED lighting. In other words, you will use your 12 volt power supply to power the back lighting in the CDU. Each LED will have it's own resistor which drops the 12 volt power down to about 3 volts. And, there are 51 LEDs that will be used to back light the buttons! The most amazing thing about this design is that it is done in only two layers. The real CDUs use three if not four layers in the PCB. Being able to achieve this design in two layers enables me to make a couple prototypes in clad using my CNC machine!

Ron 1195


I have lots of soldering ahead of me. I have 230 components to solder to each of these pictured!


Ideally, these need to be made in PCB using a program like Dip Trace. And that is where Will Sasse comes in. He will be taking this design and working it into Dip Trace. This way, if we ever have to go into full production, we can simply order as many PCBs as we need.  So keep an eye out for the CDU replica prototype!


(Posted by Shane Barnes on 05-17-17)

Nice looking boards Ron. Looking forward to seeing the prototype in action!


(Posted by Ron Rollo on 06-28-17)

The buttons are cut, sanded and painted. They are currently at the laser shop waiting to be engraved. Notice the copper clad register? It is a tool that is used to hold the buttons in place while the laser is doing it's thing:

Ron 1196


UPDATE:  The prototype button caps are back from the laser shop and they look good:

Ron 1197

There are three sets here.


In other news, I am still working hard on the Hangar45 forums. The good news is I am about 60% complete with them and at this point, I can see the light at the end of this long tunnel! I am really excited about the organization and how easy it will be for everyone to find information they need once the new website is up and running. You can see some of the results now!


More updates as soon as I got something to share!

Sorry for the long delay on updating this thread.  A lot has happened over the past six months including pulling down our old Hangar45 website and getting this new website up and on line.  If you only knew what I have had to do to get all of our information captured and repopulated!  I can see the light at the end of the tunnel....


Anyway, about four months ago I finished up the CDU prototypes.  If you recall, the main reason for building these was to get them into Jason Hite's hands so that he can continue to test the CDUs in "dual mode".  For now, our path to obtaining a CDU (or a second one if you want two) is to find a real CDU face and to use my Project45 backer with an Arduino Nano card for the interface.  This path is tested, tried and can be achieved for under $1,000 per unit if you shop around a little.  Or you can reach out to Shane Barnes and he can hook you up!  Check out this thread HERE


Knowing what I have learned this last year making these prototypes, my final product would be around $1,100 and the quality would not be what the real CDUs are.  But at least we have a backup plan if the demand ever gets crazy.  I learned a lot during this process.  This is without a doubt the hardest part of the entire build and it is in the books!


Here are a few photos of the prototype CDUs:

Ron 1198


One of the things I am very proud about with this design is that the matrix X2 (front and back) and the back lighting is all within one single piece of double sided clad.  The real UNS-1 FMS unit uses at least three layers if not four in some variations.  There are at least four different variations that all look the same in the Learjet45:

Ron 1199


The buttons are back lit just like the real unit!  There are actually more LEDs in this design than incandescent bulbs in the real units:

Ron 1200


I had to make a custom plug pin and use colored wires to insure I did not mix up the matrix:

Ron 1201


We are using the Arduino Nano interface cards as our "middle man" board.  This is replacing the Hagstrom card.  The reason being is that the Hagstrom card has issues when trying to run the CDUs in dual mode.  Which reminds me, from here on out, we are using Arduino Nano cards for this reason.  Another nice side effect is that the Nanos are so cheap that they are almost free!

Ron 1202


These are the two CDU prototypes.  They have since been sent to Shane for verification that all is good and sent on to Jason for future dual mode testing.  This is a huge investment in time that will pay dividends for us all in the Hangar and even beyond!

Ron 1203


Keep an eye out for CDU and FMS news!

Hey everyone!

Hope everyone had a Merry Christmas and a Happy New Year.  Here's to a new productive sim building year and many giant steps closer to us all having the sim we have been dreaming of!

One major step is a new CDU Replica!  The time has finally come to push the CDU/FMS Replica development the rest of the way over the finish line.  In the past we thought it would be nice to have a CDU replica if the demand ever got to a point that we needed to supplement the real world hardware supply.  But over the past year we have discovered that having a working replica would not be a luxury, but actually a necessity.

This past year, Jason and I have been fine tuning how the CDU works within the rest of the system and we found that the incandescent backlighting built into the real CDUs causes severe phantom signal key presses when the CDU is plugged into the Pedestal LCU (Light Control Module).  However, when the CDU is not plugged into the LCU and receiving isolated 5 volt power, there are no phantom key press signals and the CDUs work fine.  This is how we currently have the CDUs working in our sims.

In an effort to resolve this issue and be able to include the CDUs on the Pedestal LCU, the real CDUs need to be converted from incandescent bulbs to LEDs with current limiting resistors.  This is possible by using SMD type LEDs and resistors in some of the UNS1 CDUs.  Jason was able to convert his to LED and has resolved the issue for his test CDU/FMS.  However, I looked into converting the units I have and found that they would not be as easy to convert as the unit Jason has.  As a matter of fact, nearly impossible.

For this reason, pushing the development of a new CDU/FMS UNS1 replica is now top priority and the work has already begun!  The version of UNS1 I will be replicating will include the beveled edges on the left and right sides of the display screen.  They will be backlit via LEDs and current limiting resistors.  Other than that, they will look, work and operate the same as the real CDU units.  The pin assignments will be the same as what we have now.

So to kick  things off,  here is a great motivational photo of a pair of UNS1 CDUs!

If all goes well, at this end of this thread there will be a photo of a couple Project45 CDU replicas that look exactly like the pair above!  I plan to make an initial run of 12 CDU units.  Here are the blank front panels cut and ready for milling in a couple weeks.

This is going to be one of the most challenging projects to date, if not the MOST challenging!  Over the past five years I have developed some additional cnc and pcb manufacturing skills while working on other projects, so it was probably a good thing that this project was postponed until now.

I will try to give weekly updates of the progress with plenty of photos along the way.  I expect to have them complete within 3 to 5 months.  It's hard to say exactly at this point in time because of the complexity and trial and error that comes with a project like this.  So far we have a solid plan in place and it is just a matter of making it happen.

I am really excited to see how this turns out!  Once I get to a point where I can see the light at the end of this tunnel, I will release a price point per unit.

Hi Ron

I am also starting to create my CDU.
It will definitly not be as accurate as yours but i hope it will be as accurate as possible.

What switches/caps did you use before?


Thanks Roel!

It is going to be a fun and challenging project.  I plan on sharing everything I do when it comes to this project like all the others so that anyone else who wants to build their own panels/parts can do so and enjoy the build, if that is what you enjoy doing!  In the meantime, for those guys that would rather just purchase the CDU replica, it will be made available.

In the past Will Sasse and I both chose to use a two pin through hole switch like the ones you see in this mock up test photo.  Here I am just experimenting with different switches, materials and checking the depth of everything as it comes together.

I have a couple smaller SMD type switches scattered about because I was thinking about using them but they will not work with the plan I am currently on.  I need a switch that is taller.  These two pin switches are 6X6X5mm.  I have another option at 6X6X6mm if I need them to be a little taller.  I can also go with a thicker pcb.  Right now I am planning on .06" thick.  I can go .8" or even .1" thick if I need to, so I have easy options, I just need to get a little further into the development process before I decide which exact switch height and pcb thickness to go with.

One thing that I will have to do if I ultimately go with the two pin through hole switches is cut the legs down so that the back side of the pcb is smooth and flush.  The pcb is going to be resting on the front side of the CDU backer so the back side of the pcb needs to be flush.  See test photo.

In this photo I have four switches soldered and are flush like I need them.  One switch is not solder and the legs are not cut to illustrate why they need to be cut down.

As for the buttons, I made my own with the CNC and a laser for my early CDU prototypes.  It was a ton of work and I cringe at the thought of having to make them all like that again.  The plan forward is to have a manufacture make Silicone button keypads for us.  This process can be very pricey but I think it will be well worth the extra cost.

The real CDUs do not use Silicone keypads, but there is at least one major flight sim company out there that is using this process and they look really good!  Imagine how easy the CDU buttons will be to install.  More on that later once I get a little further into the developmental process.

As I mentioned before, I am in the process of reworking my CDU drawings.  Scale, tool path issues, depth of cut issues, corner radius issues, you name it.  When I am 100% happy with the new CDU drawing, I will send you the dxf so you can compare it to your drawing or use it as you like.

Yes i would love to see your drawings.
I deviate a bit from the correct size of UNS1 because it will better fit in my pedestral with allready mounted instruments.

I plan on using these switches: 50 Stuks 6*6Mm Doorvoergat Micro Drukknop Tactile Momentary Switch Met Led Sample Groen Geel Rood wit Blauw Geel Groen|switch switch|switch with lightswitch with led - AliExpress

They have led's mounted, and mounting a button  top also is quite easy
Do you have ever used such?


Hey Roel,

These switches are very interesting and has caused me to pause and think about them and if they would be a better solution than what I have planned now.

They are the right size, they look like they have a very strong tactile feel and they are momentary.  They have the LED included in the body of the switch which is cool because you are guaranteed to have a perfectly backlit button legend.

My concerns for the design I have in mind are they have six legs, the two extra are for the LED and although I am sure it is possible, it would add extra complications to the design.  The back lighting LEDs in my panels each require a 430 ohm SMD resistor, which makes things even tighter.

The last concern is the color of the LED.  I see they have several colors but I did not see warm white.  Have you  got your hands on these to see what color "white" is?  I am thinking they are a cool white.

In any case, nice find and you got the wheels in my mind turning to see if this is a viable option for my design.  Thanks Roel!

Yes that was my idea too , instead of mounting a lot of LED's on a circuit board, the LED in the switch itselves is nice.
I still have a few lying around and , the white LED is not warm white indeed!!
But i am ok with that.

UNS1 Replica development update!

I was hoping to have an update sooner than this but none the less, we have been busy.  The planning and drawings are 99% complete, only minor tweaking due to tool path adjustments and fitting issues are left.

The center piece of the plan forward is to use professionally made Silicone keypads to take care of all the buttons.  This will greatly reduce the amount of time it takes to build the CDUs based on the old way I was planning to make the buttons using the CNC.

Will Sasse has been giving me a hand with the 3D drawing elements of the keypads.  I say keypads because the design has the keypad split in two pieces to make room for what I call "the backbone" that will be built into the front panel to add strength.  Here are a couple screen shots of Will's 3D drawings depicting the Silicon Keypads.  Thanks Will!

The Alpha keypad:

The Numbers keypad:


Before I forget, I wanted to mention that I spent the better part of a week working on the button artwork, exact scale and the proper font.  It really kicked my @$$ but in the end, I finally got it right.  Turns out every real CDU that I have in my possession and the photos I have access to are slightly different from one another.  They remind me of snowflakes, no two are alike!

The closest font that I could find to the newest UNS1 out there is "OPTIUniversFiftySeven".  Other than stretching and compressing, the only change to the font I made was a minor tweak to the tail of the "Q".  I have a .ttf file attached to the bottom of this post if you would like to add this font to your font library.

The pcb is complete and I have ten boards back ready to go!  I opted to only start with qty 10 in case I discovered something that needed to be fixed.  So far only very minor silkscreen layer adjustments.


I took extra time and added a lot of silkscreen artwork to the front side.  Things like individual button labels, pin assignments and markings for where the resistors and LEDs go.  This will help with initial testing and assembly for the guys who want the CDU in kit form.


One of the design elements was that the rear side of the pcb has to be perfectly flat with nothing protruding out the back side with the exception of the  two 10 pin headers.  The mounting screws and the solder points for the two pin switches have to be counter sunk.  The reason for this is because the rear side of the pcb will be sitting right on top of the CDU backer panel.


Here is the CDU with everything soldered up and going through a light test!



Additionally, I have developed new CDU Modules with a set of plugs specifically designed for the Replica CDU.  This new design has both the "Authentic plug" and the new "Replica plug headers".   If you have a real CDU and want to continue using it you can.  Or later down the road, if you want to switch to a replica CDU you can.  The idea is to make things as easy as possible for us all.


This CDU Module design will greatly reduce any confusion as to what wires go where.  Everything is labeled on both the replica CDU pcb and the CDU Module pcb.  And the pin assignments match each other so all you have to do is run a couple ten pin ribbon cables between the two and done.

As a reminder, the reason why Jason and I found it necessary to develop our own CDU replicas was because of phantom signal presses we were seeing during testing last year with the authentic CDUs.  If an authentic CDU is being used and the back lighting is isolated from the other panels on the Center Pedestal, it works fine.  However, if you try to include the authentic CDU onto the Center Pedestal Light channel (LCU), phantom key press signals start fast and furious to the point it is impossible to use.

We found this to be the case with at least three different versions of authentic UNS1 CDUs all using 5v incandescent bulbs.  It is possible to convert some authentic CDUs over to LEDs with resistors, but I found that the two CDUs I have could not easily be converted and the easiest path forward was to design and build our own CDU replicas.

And with that being said, this brings me to the phantom key press test.  We saw no reason why this new design using LEDs with resistors would not work but until it is tested, you never know.   What you see here is the CDU pcb lit up along with the Engine Panel and I went ahead and threw in a Davtron clock because it is using 5v bulbs.  All of these panels are on the same LCU channel and I am able to dim them all together perfectly.


To answer the big question, there were NO phantom key presses!  I spent the better part of the day testing and testing and testing.  The results were perfect.  I set the PWM dimmer at different levels, off, low, high and in all cases, everything performed like it should.


This just in, I order fifty 10 pin ribbon cables three weeks ago and they just showed up today.   They are 10" long giving us plenty of length to twist and maneuver back to each connection point.  This is a much better solution compared to the early prototype version.


Next is to build a couple CDU backers and get one of these in Jason's hands for further testing.  There should not be any issues but at this point, we don't want surprises.

I also need to pull the trigger on one of these Silicon keypad manufactures to see if it is even possible without spending a small fortune.  Plan B would be to make them with the CNC.

More updates soon!

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Looks VERY nice Ron
Did you create the PCB yourselves??

I ran into the issue that i need multiple layered PCB voor the CDU.
Double sided copper plate isn't enough for this anymore.
Well i managed to create a "worakaround" but doesn't look as nice as this for sure!

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