Following on from this thread, I think I'm now ready to start on the long and crazy path down building my own custom MFU using an Arduino Mega and some additional bits and bobs.  Big shouts must go to @Ray_ve and @Nobbi1977 for their quick advice and useful info, without which I might have lost faith in the project and let it stall. So, what have I got planned, and will it all get done?  Well, who knows for sure?  This will be a fairly open-ended project and could keep me busy for a few wee