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CDU's by A.J. Simulations and Project45

(Original thread started on 04-23-14 by Shane Barnes)

Back in the winter I began looking at an interfacing solution that would allow us to use a real CDU in our builds. After doing some research I found that a Hagstrom USB keyboard encoder will work. The Hagstrom board is simple to program and I believe that the program file can be shared with other uses.


Here is a link to the Hagstrom board:


Once I found that the Hagstrom board would fill our needs, I contacted Ron Rollo and shared the information with him as we would need parts made to bring the CDU, Hagstrom board, LCD screen and cables all together into one package. Ron has taken on that task and has done a great job. I will let Ron take it from here and show you the results.  I think that you will really like what you see.


I am actively looking for CDU units at this time. I have attached a photo below of the unit that is needed. I have seen these units sell for $150 to $500 dollars, of course we want to get them on the low end to save money!  This is only the front panel without any of Ron's parts or the LCD.  Stand by for those photos from Ron!

Shane 114


(Posted by Ron Rollo on 04-23-14)

Thanks Shane for starting this thread. I wanted you to start it because your the guy who pushed the CDU into the light!


Because of the preliminary work that Shane and Alan did with the CDU before I put my hands on it, I can say this was one of the easiest aspects of the sim to date for me. I was really worried about it and I was afraid that we would have to make this things from scratch and on top of that, the price point would be well over $1,000. But as it turns out, as long as you can find and have a CDU refurbished by Shane (or do it yourself), there is a good chance you will end up with your CDU for around $700 when all is said and done. AND, it will be a real aircraft part that has and will stand up to the test of time!


So first things first, contact Shane and get on the wish list for the front face of the real CDU. Or, do some searching on your own and obtain one. I have no doubt that anyone who wants one will have one within a reasonable amount of time.


Now for some photos of the parts that I had to fabricate. There is a CDU backer panel and a CDU PCB. The PCB will hold the Hagstrom board in place and also act as wire management. The trick was to convert the pins from the CDU to the ribbon cable that will plug into the Hagstrom board:

Ron 1204


Here is a closer look at the two main parts mentioned above. By the way, the back lighting for the CDU is 5 volts which is what the real Lear45 uses for it's back lighting. As you know, we opted to go with 12 volt lighting for many reasons so obviously we have a conflict here. I tried to use the 12 volt PWMs but the 5 volt incandescent bulbs do not like it much at all. So what I am going to do with mine is use a 5 volt power supply controlled by a relay. If you look close on the PCB, you will see a nylon plug for the 5 volt lighting:

Ron 1205


In this photo I have the CDU that Shane refurbished and my parts mounted together. You can see that I have the pins plugged into the CDU PCB. Because of where the USB plug is on the Hagstrom board, I had to design the ribbon cable to "fly over" the board from one side to the other. You will see that later:

Ron 1206


Jason Hite pointed us to a site in Singapore that supplies small LCD screens. I found one that fits perfectly in the CDU. $35.61 with free shipping if you don't mind the wait.

Ron 1207


The technology these days is stupid crazy! For $35 you get something this small and thin! This LCD screen is only 1/8th inch thick. That is the same thickness as the backer panels that we all have!

Ron 1208


I designed the backer so that the tolerances are snug but not too tight for the fitting of the LCD screen:

Ron 1209


Photo of the front side. I am going to find some black foam tape to wrap on all four sides of the LCD bezel to hide it and to also keep the back lighting from leaking into the screen area. I'll have photos of that soon:

Ron 1210


Two small pieces of aluminum tape are used to help hold the LCD screen in place. Between the hole being cut near perfect, the aluminum tape and the center pedestal frame, the LCD screen is not going anywhere!

Ron 1211


There is a sub module that goes with the LCD screen. On this sub module are things like a 12 volt power supply line, a VGA video line, remote controls for things like on/off, brightness, etc... and RCA jacks. I found the easiest way to deal with the mounting of the sub module was to attach nylon standoffs and then superglue them to the back side of the LCD screen body. (We can get away with doing it like this because it does not have to be airworthy and the FAA is not looking... right??)

Ron 1212


Here is an overview of the CDU with all components in place including the ribbon cable fly over:

Ron 1213


Last but not least the front side pretty much ready to go:

Ron 1214


I will have some more photos of the CDU with the back lighting working and the foam tape around the bezel soon.


As always, we will release a kit version of the CDU and also make available a plug and play version. The kit version will be around $50 but the end user will have to supply the Hagstrom board (approx $100) and the five inch LCD screen (approx $35).  Thanks again to everyone, especially Shane who helped make this thing happen!


(Posted by Shane Barnes on 04-24-14)

In reference to determining the backlighting voltage: Look on the back of the unit . . usually there is a dome sticking out and should have the backlight voltage printed there. I have not seen any with 28v backlighting in the particular model we are using.  Yours might actually be 5v. But would check to make sure, you never know. The unit I have has an internal clad in the front plate with the switches and bulbs attached. It would be difficult to replace the bulbs as you would need to de-solder and solder bulbs back in place, not saying impossible, just saying it would be time consuming. Hopefully you will find that your unit is actually 5v. Careful when you take the unit apart.  One style has tiny springs and nylon plungers under the switch cap. Would not want to lose any of these tiny parts.


You will also most likely find the voltage on the back side of the front panel once it is removed from the large black box.  You won't need the box.


In reference to part numbers: Here are a few part numbers I located on the back of the front panel. P/N 865-000023-1 and PN 00101670-01 These are made by Univeral Avionics.


(Posted by Will Sasse on 04-26-14)

For those of us still looking for a CDU/FMS, here is some specific detail as to what to look for:

The faceplate used for the UNS-1E and UNS-1Ew is the same as the faceplate used on older FMSs; namely the UNS-1B+, UNS-1C (all-in-one FMS), UNS-1D, UNS-1F and the current model UNS-1Fw FMS.


For the UNS-1B+, UNS-1D, UNS-1F and UNS-1Fw FMSs that have a separate Nav Computer and CDU, the CDU part number will be P/N 1018-X-XXX. The CDU faceplates come in either gray or black color. The Lear 45 uses a gray colored faceplate.


I have it on good authority that Universal has made rather a lot of CDU's, so hopefully examples in our price range will appear.....

(Posted by Ron Rollo on 04-27-14)

For those guys who either have a CDU or are on the wish list for one, I have determined what the cost will be for the CDU Basic Kit and the CDU Plug and Play version. (Front CDU panel for either the Kit or the Plug and Play not included in these prices)


The CDU Basic Kit will consist of the 1/8th inch CDU backer, the PCB panel and the hardware that will be soldered to the PCB. This basic kit will run $40. The user will need to purchase the 5 inch LCD screen, Hagstrom card, ribbon cable, other misc hardware and complete all the soldering.


The CDU Plug and play version will include the 5 inch LCD screen installed, Hagstrom card installed, everything soldered and all hardware included. This package will run $295. All the end user will have to do is add the CDU front panel, a USB cable, a VGA cable and a 12 volt power line.


Let me share some more photos of the CDU with everyone that I promised. In this photo, I am getting ready to cut and install some black foam tape to hide the bezel to the LCD screen and to also help block some of the back lighting that I saw leaking from the panel:

Ron 1215


Here is the tape installed on the bezel. Nothing to it:

Ron 1216


I ran all the cables that are needed to operate the CDU. I am using a 25' long VGA cord and a 25' long USB cord. The 12 volt line that supplies power to the LCD screen runs to the right ESS power BUS. The 5 volt lighting line for the back lighting currently runs to a relay that is controlled by a 12 volt line coming from the right ESS power BUS. So basically what this means is the CDU turns on when the right battery switch is turned on along with everything else on the right side of the airplane:

Ron 1217


Here is a photo of the back lighting and the LCD screen lit up in it's beta test mode. I still have not got it hooked up to the computer but that will change soon enough. (Sorry for the poor quality photo):

Ron 1218


(Posted by Mike Badger on 04-30-14)

Can the front bezel on these be cleaned up much? If I find one that looks a little worn can they be taken off, sanded and repainted?


(Posted by Shane Barnes on 05-01-14)

Hey Mike, the front panel is fairly easy to clean up and repaint. Even if you find one that is black it can be repainted to a more "correct" color and normally the white silk screen "UNIVERSAL" at the top can be saved. How easy it is depends on which version of CDU that you have. Two different internal styles that I know of so far. . one is fairly easy . . one is very time consuming due to small springs and plungers under each switch. It is usually somewhat difficult to tell between the two externally in photos. But you know it when you open it up!


(Posted by Shane Barnes on 05-07-14)

Click on the photo for a very short video showing the LCD screen working behind the real CDU. I have positioned the default GPS screen to give you an idea as to how it looks. This is only for testing purposes as Jason continues development on the CDU software that will provide the correct look to the on screen information. The Hagstrom board has now been tested with Ron's parts to ensure everything was working as expected . . of course it passed with flying colors! So at this point we have working CDU hardware and awaiting the CDU software development that will bring this part of the project to life!


(Posted by Chris Capkalu on 07-22-14)

Does anyone have a source for the UNS-1E for buying? I searched the net for weeks now, nothing to catch  Faceplate only with buttons would also be fine...


On ebay there are a few units, but not the try is to write an email to the guys of APHS, they have a lot of parts or can catch them from others. Mostly Boeing but worth a try maybe.


(Posted by Shane Barnes on 07-22-14)

Best bet for now is watching eBay.  Use search terms such as CDU, Control Display Unit, Universal UNS-1 when searching for units.  Also using advanced search where the search engine on eBay will also search item description is helpful. I have not found any other sources for the CDU at this time. Good luck with the search!


(Posted by Randy Buchanan on 10-14-14)

Here is some information on which jet aircraft uses which version of Primus:

The Lear45 uses the 1000 version.


(Posted by Ron Rollo on 12-31-14)

Just a quick update on the CDU. Jason sent me a pre beta test of the CDU software (I guess that would make this an "Alfa test") that he has been working on. If your one of the guys that just has to have this software in your sim, your gonna love it!


Here are a few snap shots of the software working with the hardware:

Ron 1219


Ron 1220


(Posted by DonnyRay Jones on 04-10-15)

I've been away for a while, busy with other stuff, but am finally back to building. I haven't been in the Hangar in a long time either but will try to slog thru and catch up and perhaps lend some help as I can. I saw the discussion in this thread about the FMS panel lighting.


In many avionics boxes and control heads the lighting INPUT voltage (from the airframe) does not directly drive the bulbs/LEDs/EL film/wax candles or whatever is used in the panel itself. Most of these type boxes contain a tracking regulator that drives the bulbs. The lighting input voltage from the airplane drives the regulator and the regulator drives the bulbs. With such an arrangement you can easily configure an LRU to match the particular airframe at hand. Thus a limited number of spare units can be used across multiple airframes by simply changing lighting jumpers inside the unit. Those jumpers tell the tracking regulator how to "scale" the lighting input voltage to match the dimmable range of the bulbs/LEDs/EL film/wax candles, etc.


Universal has gone through several design revisions and used a variety of panel manufacturers during the life of these products. On EARLY model CDUs the lighting voltage selector is located on the motherboard in the rear of the unit. As I recall it's labeled "E1" and "E2" for 5 volts vs. 28 volts. You can switch those around easily. But that won't help you any if you're not using the innards of the original CDU. And even if you are using the innards - you have to power up the entire CDU to make the internal lighting regulator function. You can't simply apply voltage to a couple of pins on the rear and get the bulbs to illuminate. LATER models of these CDUs don't have the internal jumpers on the motherboard. Regardless - all you want to know is what bulbs are used in the front panel. As others have said, look on the backside of the front panel and see what bulbs are installed. Most of the Canadian Marconi units (CMC) are built with 5 volt bulbs while the early Bell units used 28 volt bulbs. Find those pins *on the front panel itself* and bring those out to whatever dimming system you use in your rig.


(Posted by Ron Rollo on 03-13-17)

I am exited to announce that Jason Hite with Flight Deck Soft has came up with a new and improved solution for the CDU/FMS! First let me explain what the issue was that prompted him to research and find this discovery.


The issue: The Hagstrom card which is the interface card that we currently use for the CDU works great if you have only one CDU. It is also a little on the expensive side at close to $100 as you know if you have purchased one. The problem identified is that if you plan to use two CDUs in your simulator, you will need to install the Hagstrom software on two separate computers to get them to work properly, otherwise, the key strokes from each CDU will conflict with the other CDU if they are on the same computer. With that said, we could resolve the problem with two computers and two $100 Hagstrom cards and of course additional programming and set up.


The solution: Jason has discovered that the solution to this issue is the Arduino Nano interface card!

Ron 7

First, it cost is less than $3 per unit!


Second, we can run two CDU/FMS's on the same computer with no key stroke interference with the other.  (You will need on Arduino per CDU.)


Last but not least, this solution will be true "Plug and Play"! Unlike the Hagstrom card which required setup, and assignment of the rows and columns, Jason has done all the setup and it will be included with future software releases or updates! Once the software is down loaded to the Arduino Nano, your done! (As long as the real CDU/FMS is wired in the same matrix as our known CDU/FMS's that we have acquired so far.) Worse case scenario would be that we would reassign the pins on the Nano which would take just a few minutes.


So again, a big thanks to Jason Hite for the continued development of the CDU/FMS software! One additional point, future releases of the FMS software will be geared toward this new Nano solution and the old Hagstrom solution will no longer work. And that is where I come into play. I have developed a new clad board to accept the Arduino Nano and I will be sending out a FREE upgrade kit to everyone who already has a CDU from Shane and or the CDU kit that I have made. Here are a couple photos of the new Nano solution:

Ron 8


Ron 9


If you would like to get up to speed with this new solution, please post here or email me! This update kit will include everything you need including the Arduino Nano interface card and even a new smoked lens to give you the option of swapping your original lens out if you want. Again, thanks to Jason for his continued work and development of the FMS software!


(Posted by Douglas Dick on 03-28-17)

Great to hear that the update to the FMC has been released and the move to Arduino, thanks Jason for your hard work! Can anyone confirm if there is an Ardunio sketch to be loaded on to the nano and what the pin configuration is?


(Posted by Ron Rollo on 03-28-17)

Yes, there is an Ardunio sketch to be loaded onto the Nano. You will need my Nano Clad if you want a clean looking solution even if you already have a CDU and the Nano. Otherwise you would need to use jumper wires to the pins. What we are trying to do is develop a hassle free, plug and play solution for everyone no matter if you have your own CDU or you obtain one from Shane. Email myself or Shane so we can get you that file and or the Nano Clad board:


(Posted by Shane Barnes on 04-17-17)

If you are upgrading to the Arduino based CDU you will need this USB cable as the Arduino uses a different USB cable than the Hagstrom. I found this one as an example for what you will need. You may be able to find one cheaper at other sites. Also this one is 15ft long. This gives plenty of length to reach the rear of my shell where the CDU computer is located. I have tested this cable and it works well with the Arduino.

You can find these cables at HERE