> >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

 > Assuming that you are trying to stay with a video display, I think

your

 > sunlight readable display is going to blow your budget.  There's a
 local
 > RV-4 builder here in the Portland area that has built a few

iterations

 of
 > engine monitors (for Lycs) like you describe.  Rob's latest uses a

new

 > Sharp (I think) display that is comparable with the
 > iPAQ.  http://advanced-control-systems.com/
 >
 > (Wow, I just looked at that link, he's really improved the thing

since

 I
 > last saw it, along with the price.  8-o  )
 >
 > One could certainly build your own thermocouple probes a lot

cheaper

 than
 > you can buy them.  Brass/aluminum/stainless plugs, epoxy and
 thermocouple
 > hookup wire.  the TC wire end MUST be welded so you need a torch

along

 with
 > a drill for the plugs.
 >
 > What's left, a board with controller, memory, video output, and I/O
 > structure?  Doesn't one of the "stamp" units do all this?
 >
 > I think you are going to need a $500 budget to get this to a real
 > user/pilot friendly level with adjustable/programmable alarm points

and

 > indication ranges.  Maybe I'm still stuck inside the box thinking

of

 off
 > the shelf components?
 >
 > Mike
 >
 > Mike McGee, RV-4 N996RV, O320-E2G, Aurora, OR
 > 13B in gestation mode

 Hint: Cost not counting the sensors. You need those with whatever.

 Paul Lamar

[Todd TC. Carrico]
PIC's are pretty cheap especially the 16F6xx serie
¦ÀLimited IO Pins.

The 16F628 has two onboard A/D, two timers, hardware PMW, and around 12
io ports.

About $4 usd each.  Much cheaper than the Stamp.

For display, you could use an LCD, stick with two lines and get around
$50 bucks.  There is always 7 segment displays, and you can get a driver
for them for under $10.  It takes 2 or three lines from the PIC.

My plan was to have separate modules that are strung together on a CAN
bus.  You will still need a "Brain" to put all of it together.  This
system would probably put you over the $100 limit (not counting the
display).  It would require a PIC, and a CAN chip for each "sensor".  My
goal was to build discrete assemblies so they could be tested and
developed in small steps.  Failure of one would not affect the others
(unless it was the brain, but you double up on brains...two heads are
better than one eh).

It really sounds like the big problem with $100 is the display
mechanism.  The alerts could be made audible, but I am not sure if you
use that to replace the actual indicator.  I would want to be able to
see the reading after being warned of it.

To keep it cheap, we are going to have to find a way to maximize the
display, stick with simple sensors, and a low parts count.  I am not
sure I added anything to this...

tc

 
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