NetAvionics : Rapberry Pi setup for cockpits

Hello,

I’m now working at home, due to Covid, and that spares me a lot of commuting. I have improved many aspects of the project, and in particular, while expanding the capabilities of the hardware control, I have come close to the limits of the arduino DUE. The reason is that I’m now reaching the memory and speed limits of the device. Although I could go on with the existing design, I have started to investigate a replacement of the DUE by a Raspberry, which is way more powerful. The drawback is that the Raspberry has a limited input/output port capacity, compared to the Arduino DUE. In a first step, I am experimenting with a Raspberry/DUE combination, where the DUE does a minimal work of handling the hardware input/output, digital and analogs, and the Raspberry does the “smart” job : communicating over the network with the simulator, mapping hardware values to real values (for example for servomotors and analogs, often in a non linear way…), handling a configuration file which hides the hardware structure and exposes increased functionalities …

It’s also possible to use a raspberry alone, without Arduino, but this implies a redesign of the expansion card which is used to connect to the opencockpit mastercards. This is my prefered approach but needs more work. My problem is that I have more ideas than free time to realize it, but this project is improving constantly.

Continuing to work on the FMC; it’s a huge work so I’m progressing more slowly than I would like. Another aspect I have been developping is the implementation of the overhead. The overhead controls all the systems in the plane, so there’s a lot of interactions and complexity. I wanted to do something which can be easily reworked and improved, so I decided to use scripts. X-plane comes with a native implementation of LUA, which is a powerfull scripting language. I have made a script to define “datarefs” containing the state of every element of the overhead panel. These are variables that can be manipulated in the script to simulate the behaviour of the systems controled by the overhead. The overhead hardware state is fed into these datarefs (that’s a lot of switches and knobs !) , so they can be used to programmatically simulate all systems.

Using this approach, I have designed an “open” system which can be easily edited to modify, correct or improve the simulation of the overhead by the end user with a minimal knowledge of programming. This script is contained in a modified version of the Laminar B738, in the folder /X-Plane 11/Aircraft/NTAV B737-800/plugins/xlua.

I have also decided to write a manual for the system, as it is becoming larger and larger and has more and more functionalities and options. I will release it here as soon as possible.

Happy New Year !

The project is in good progress, the FMC is on its way, and it’s a huge work, I must admit that I had underestimated it. Well, I want to obtain something very close to the real thing, and it requires a lot of efforts. I think I will need a few months more to obtain a first satisfying version.

Hardware : simpler, plug & play connection to the opencockpit master cards with a professionnal design !
I have designed dedicated electronic boards, all SMD component design, which just require to plug cables to obtain a working system :

The DSTACK card is the hardware processor, based on an Arduino DUE and handles easily 576 inputs and 360 outputs. This card has a wire connection to the network, to communicate with the X-plane dedicated plugin. I have also increased the number of servomotors to 15 and analog inputs to 14. On the bottom of the picture, notice the two connectors to connect two expansion cards, depicted below

The NetAvionics (NTAV) expansion card is fully compatible with the opencockpit USB expansion card, and it allow similarly to connect 4 mastercards using the same connectors and cables (25 pins SUB-D). Two such cards can be connected to the DSTACK card, using the 26 pin connector at the center. A Servomotor card allow to connect 15 servomotors, using a serial connection which allows to use up to 20m (60 feet) long cables. This design is also necessary because Arduino DUE has 3.3V outputs while usual servomotors expect 5V control signals. The board both handles the voltage leveling and allow noise free control over long cable lengths.

Hello !

I’m working hard on the fmc. I have chosen to rely only on the X-Plane database, no data files will be specific to the FMC, in order to ensure a clean synchronization between X-Plane and the FMC. Any update of the X-Plane files (including using services like Navigraph or similar) is transmitted automatically to the FMC.

I didn’t imagine how complex the FMC route editor has to be. Just try on the FMCs you known to edit the legs list, containing airway segments, and look at how this is reflected on the route waypoint list, for example. I am really decided to reproduce the real thing as closely as possible, and I’m now taking the full measure of the amount of work needed !

Long time, no news !
But the project is still ongoing, and well !
I now have all the screens (PFD, ND, engines, …) working fine, except that weather radar and terrain radar are not yet implemented. All the cockpit hardware is supported.

I am currently working on a FMC independent of Xplane, which is based on a Raspberry pi Zero. The little Raspi has a composite video output, which is perfect for driving my recycled PS-one screen and the 69 keys FMC panel is handled using pushbutton matrix connected to the Raspi GPIO port.

Here are two pictures :

Hi !

Still workin’ hard ! I have finished all “basic” screens, i.e. PFD, ND, centered mode ND, Engine screen (upper DU) and MFD (both ENG and SYS). I am currently working on the TCAS implementation in ND and PFD, designed to work with AI planes and also online networks (IVAO, VATSIM). Next, I will work on the weather and terrain radar in ND, which are not implemented yet.

I have a test configuration running in my B737 NG 800 cockpit, which uses 4 raspberrys and one DSTACK, pretty cool … I will had a small video soon. I am also debugging the hardware part, but it’s pretty stable and easy to use.

I am also now thinking to add raspberry pi zero based FMCs. The power of the pi zero is enough for that, with a GPIO connector which hold enough pins to connect the FMC keyboard. But that’s for later 😉

Hi,

I’ve been quite busy working on the system. I’m almost finished with the engines primary instrument screen (upper DU in the B737). Here are two rapid screen shots taken with my phone:

I have noticed that I have slightly different element placements depending upon the type of screen used and its resolution. I have decided to include a lot of user modifiable parameters so that “fine tuning” can be done for specific screen by a non-programmer, using a user friendly GUI. I am now doing the same for the other screens (PFD, ND) and I still have a lot to add to these. I am trying to follow as closely as possible the Boeing documentation to implement a maximum of realistic behavior.