Category: FMC

FMC Now Functional

Didn’t take as long as I thought as the FMC unit is now up and running.

I’m using an OpenCockpits USBKeys Cards and a custom PCB I made for my FMC.  To bridge OpenCockpits SIOC to the PMDG 737, I’m using the OCP4NGX software.  This software is primarily used for OpenCockpits Plug-&-Play modules, so custom built stuff like my FMC will need some script tweaking to make it work right.

So with the OCP4NGX Software,  the first thing I had to was manually set my KeyCard to be Device 13, what the software uses for the Captain FMC.  Once I got the variable set and the card recognized, the next main hurdle was my FMC PCB board’s key matrix wasn’t wired the same way as an OpenCockpits Plug-&-Play FMC would be, so the key inputs didn’t match up.  I was going to have to manually map each key on the FMC to appropriate SIOC input #.   After some internet searching, I found this required the following SIOC code for each key

if &KeyPressed = 20 // A
&CDUKey = 61 // Prosim value
&CDUKey = 0

Peter at Build A Boing had the same issue a few years back and shared his final code on the prosim forums, thus saving me a good deal of work of writing the whole thing from scratch.

Once I updated the first line to match what SIOC Monitor was reporting as the key # for each FMC key, my FMC worked great.  I have my FMC code available here.

Here’s a quick video testing the unit:

Throttle Bay Progress

This weekend I was able to get the final bits of wiring done on the Throttle Bay and began programming all the inputs.  As of last night I was able to get everything setup in FSUIPC in P3D V4 except for the FMC keys.  I’ll need to use opencockpits SIOC for that, so that’ll be this weeks project.

Throttle Bay

Of course it wasn’t until I was programming the toggle switches I noticed I have the “off” and “on” labels for the logo and collision lights reversed.  Whoops.

I was hoping to make some progress on the MIP wiring but I ended up running out of wire, so that’s on hold till my reorder of wire arrives this week.


So in the mean time I started working on a overhead panel project.  For this panel I was thinking rather than having all the text and such etched on the panel directly, I’d create a printed overlay with it all along with some colored panels.  This way the panel could just be made with the cutouts for indicators and switches, cutting it’s cost by 50%.  It’s an early look at the photoshop file for the overlay.


August Updates

Been a while since my last update, I’ll try and recap everything that’s been on.


I left with the ordering of a custom PCB board for my OpenCockpits FMC Kit.  They board arrived in a couple days and looked great…. at first.



At first I noticed I goofed on the pin spacing for the resistors, then I next noticed I had the pin spacing wrong on the header pins for the LEDs and backlight inputs. I though no problem, I cna work with that still. So i went and soldered all the SMDS and switches in place. And that’s when I when I found the big error. I completely missed including some switches into the traces. So many of the switches didn’t. Doh!

So it was back to the drawing board. I updated the design to move all the resistors to the back of the board in a single spot, redid the wire diagram for all the switches and also redid the diagram for the backlight to make sure they were correct too. And fixed the header pin spacing. The 2nd boards came in and this time, everything worked. 🙂


So with the PCB project now complete, the assembly of the FMC is slowly underway.


737 throttle

My original plan for a throttle was still up in the air. With Jetmax no longer selling their throttle unit, I was looking into building a housing to use a Saitek throttle in.  And the 1 day my phone dinged. It was for a Jetmax 737 Throttle that showed up on Ebay.  After a quick look over the pictures, everything seemed to be in good condition so I jumped on it.  A few days later, I had my throttle problem solved.

Throttle Throttle Throttle Throttle Throttle

I plan on building a small CDU bay to go in front to probably hold a few custom panels with some buttons and switches on it.

Other Stuff

I’ve pretty got my MIP layout finalized.  I’ll have to put together mock up but basic plan is to put the FMC on the left side, 3 displays and then MIP switches like landing gear, flaps guage, etc..  The top portion of the panel with have the MCP unit, sixpack indicators, master/fire switches and the COMM and NAV radio panels.  this way I keep the bulk of the wiring and I/O cards contained into a single unit.

Speaking of MPC, I recently picked up a OpenCockpits MCP from them last week.  I’m trying to get most of the panels I need in order to finalize where cutouts need to be in the MIP panel as I plan on getting a metal frame fabricated for it.


Ended up with the Honeywell version as that’s all they seem to sell now, but I do like the custom knobs on and was delighted to find the unit comes with backlighting installed already.  I haven’t tested that out yet though.

I’m also working on some PCB’s for my Comm and Nav panels for the 7-segment displays, so I’ll show those off whenever I get them done and fabricated.

That’s about it for now.

FMC PCB Design

My current project has been working on the PCB board for the FMC unit. Opencockpits used to sell one but no longer does, so I decided to create my own in DipTrace.

I used the included clear panel in the FMC Kit as my guide to laying out all the button locations and screw holes.  I also added in some pads for small SMD LEDs for backlighting.  Here’s a look at the 3D render from DipTrace.


I’ve got my fingers crossed that I have the tracing down correctly for the key matrix.  I submitted the file for fabrication to EasyEDA last yesterday.  Will probably take about 2 weeks to arrive from China.

I normally use USA based for all my small PCB boards, but because of the size of this one I went with EasyEDA as it was waaaaaay cheaper ($20 for 5 board min vs $150+ for 3 min.)

FMC Test

Quick test of the new FMC with the 737NGX.

I still need to wire all the LEDs in the unit to the Mastercard and glue the top handle on. Here’s what the EXEC light will look like and how the unit looks in the CDU Bay.

Interfacing was easy using the OCP4NGX scripts. He has built-in support for the Plug-n-play version, so the DIY works just as well since they both models use the USB Keycards. Just need to set the SIOC.ini to point to the USBKeycards device and make a VAR change in the script to point to that device.

Overall, the build came out pretty good. Some of the buttons came out a little crooked when you view the unit from the side, but top down you can’t tell. So not that big an issue.  Saved about $180USD by building the FMC myself instead of buying the plug-n-play version.

I hope to have a guide on the construction up soon.

CDU Bay Progress

Assembled the CDU Bay tonight.  Went together very easy. Didn’t need to sand anything to make it fit.  I picked up some Confirmat Screws as they are recommended to use on MDF (helps prevents splitting since they are not tapered.)

Once I get some wood putty I’ll fill in all the screw holes, sand it, and then seal it for painting.

Speaking of paint, if you need some RAL 7011 Boing Grey paint, you can find it at Sherwin Williams. Check there site to find a store.  It’s official name is RAL 7011 Iron Grey.  Only $8 for a sample quart.

Weekend Progress

Got the frame for the overhead completed.  Yesterday I gave it a coat of gray primer (and will probably leave it like that) so I’m just giving it 24 hours to cure before attaching panels.

Works on the FMC continues as well.  I have the switches all assembled and soldered to the PCB board.  Also installed a 40-pin header for connecting the USBKeys card.  Next step is to the glue the buttons to the switches.  I also ordered a 5.6″ LCD Panel which should be here in about 2-3 weeks probably.  so hopefully that works well.

The opencockpits kit doesn’t have an EXEC key that can light up, so I’m removing the button for the brightness dial just above the EXEC button and replacing it with the top portion of a gutted green LED indicator from radio shack I already had on hand.  It fits the hole perfectly and will light up for the EXEC button.

Opencockpits FMC Kit

Received my Opencockpits FMC kit, PCB Board and components the other day.  The parts themselves look nice but there’s no documentation at all on how to assemble.

I’ve kinda figured out the PC-Board replaces the white board that comes in the main kit and I think get how the rest of the plates and buttons go, but it still would be nice if O/C published some tutorials on it so people know what they are doing to avoid screwing up an expensive kit.  Another example is the components kit includes a couple LEDs, but I have no idea what they are for.   Backlighting some portion of the face I’m guessing.

I was also  little bummed that it didn’t include a few basic screws/bolts to fasten all the plates together. Nothing a trip to the hardware store can’t fix but I seems little a given that these basic parts need to complete assembly would be included.

But still looking forward to getting this little guy assembled soon.

I’ve also started working on the frame for the overhead panels so I’ll post updates on that as it progresses in the coming days.