Just a quick update. I have the proposed board schematic built on breadboard bar the pyro cut down. Generally it all seems to work apart from a nasty buffer overflow that caused all manner of reboots and crashes. It seems occasionally the GPS sends null chars when it doesn’t have a lock, when the Arduino tries to do maths and stuff on nulls a small portal opens and the world disappears.
Anyway I’ve put some null catching code in there to prevent this and it seems stable now. Whilst trying to right up the pyro circuitry I’ve blow the 3.3v regulator so I need to work out why, the microcontroller and GPS are fortunately ok.
Hopefully once I’ve done with designing the board for Project Swift this weekend I’ll crack on and finish the prototyping off.