The product this is being done for is nothing to do with aviation.
Once it is done, I will look for opportunities for converters for various purposes 
When will you test it ?
Which ADSBIN/FLARM box will you choose as input ?
I’ve added CAN
So now I have CAN, RS232, RS422, RS485 and ARINC429 on the same box.
Definitely CAN. All new engines (Rotax, ULP etc) use CAN. Many EFIS’es use CAN to communicate with boxes (they have to, or they won’t get any engine data).
CAN (and LIN) are still kings in automotive and the stuff is quite standardized so not much is proprietary beside, of course, the application communication layer. On top of these there is more and more lately cybersecurity added so reverse engineering is difficult.
Dynon has CAN also.
Yes; it will be user-programmable, with the usual free development tools.
There is analog stuff but I am not posting the details
CAN bus is interesting. After massive hype 15-20 years ago it has almost totally died out in the industrial control sector, while living in cars and some other areas e.g. Experimental (and later some Certified) category avionics. I suspect the avionics angle may be tricky to exploit since it all be proprietary, and protocol analysis is tough. The vehicle stuff is proprietary but due to the huge interest a lot of it has been reverse engineered (VAG-COM etc). This box has two SPI interfaces so anything-SPI can be added. The ARINC429 chip (which like everything-ARINC is not cheap – about $100) is an SPI peripheral…
ARINC429 is either documented, or it is undocumented but fairly easy to reverse engineer due to the one-way data flow and usually obvious packet content.
@Peter, are you planning to make it a multi-purpose hardware platform? In this case, I’d also add CAN bus (which is used in the Garmin device ecosystem and possibly elsewhere) and some analogue and discrete I/O pins.
Just a quick update, in case somebody finds this when looking for something else the design I am working on has
The CPU is an ARM running at 150MHz so loads of performance.
There is no wifi or bluetooth but they can be added.
So if anyone is after some custom data converter, or has some product ideas, let me know.
That would require a wifi client, basically running the Golze app source code, and then converting that into a radar image. I think all the protocols for that are commercially secret, though perhaps less so for ARINC429 radar data for which I vaguely recall seeing a spec somewhere, but then what device is capable of displaying that?
