OK lets think out side the box.

How can we build a complete engine monitor that will monitor
a dozen engine parameters with alarms and will be usable in bright

sunlight

and will take little room on the instrument panel of a tandem
seat airplane? Also it must cost less than $100 to build.
Paul Lamar

look at digital panel meters for the display. they can be calibrated by a
pot  use as a voltage divider  and a pressure or temp source.
using a analog devices ad 594 or 595 and a pot the egt or cht could be
displayed. the panel meters are available through surplus supply sites for
as low as 5-7 $ each.  for a few bucks more comparators can be made from op
amps and used to drive leds for visual warnings. i think a unit could be
made for less than 100$ using these meters.
smale@ncinternet.net

 
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