Paul replied to someone:

 OK now we are getting down to it. Button A should then be a selector switch
 right? Or a simple push button with one push and each function name would
appear
 on the screen in order. Another button excutes the order. Or... hold down
button A
 for two seconds? Next push on button A...  next function. Right?

Hi Paul,

My thinking on the EFI display would be to incorporate a nominal terse "idle"
display that would just say "O2=OK" for example if the parameters are within
a programmed range.  Let the electronics help you out when you are flying,
not lead to information overload.   When a parameter goes out of normal range
let that part of the terse display flash.  You can then use your scroll
through menu to get the full picture when flight duties allow it.  You can
also use this scroll through the menu mode to check all the parameters when
you are needing that data for performance testing and so on.

So normal monitoring of the EFI display during flight would be just a quick
scan to see if anything is flagged by flashing.   Normally, trying to
interpret a bunch of digitally displayed numbers  is not the most efficient
way for a pilot to monitor functions, analog displays are best.  Thankfully,
those goofy digital speedometers in cars are all but gone now.

As far as holding buttons down for two seconds and such, those sort of things
are kind of annoying and distracting to do while trying to fly because you
have to watch it for the two seconds to see when it kicks over to the other
mode.   If you build that feature in intending for it to be ground use only,
someone will still be fiddling with it while flying though LAX airspace ;^)
Your concept of a single toggle switch to scroll up or down is probably the
most elegant interface control.

Carl Turner

Yes. I used that trick 20 years ago on my computerized road test equipment.
You used the toggle switch to scroll up and down through a list of 30 programs 
and when you found the one you wanted you pressed the go button. Worked great
with a modest LCD.

Well that is three for terse. Zero for verbose. How about cost? The price people
are willing to pay is going to determine the size of the LCD and the
amount of programming to be done. To be realistic the programming cost
must be divided by the number of sales. Since we have a limited market
here it should be kept simple.

Think of this as a marketing focus group.

I need to hear from more people on this.

Paul Lamar
 
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