[simpits-tech] Beech Flap Gauge

[Matt Bailey]

On Thu, 29 Jan 2015 21:39:25 -0800
Ray <raysot at comcast.net> wrote:

> 
> Everyone,
> 
> I've acquired a nifty flap gauge and want to interface it to an
> arduino. Has anyone done this yet?
> 
> I think Gene may have this figured out a long time ago.
> 
> http://anthonyscottphotography.com/flap
> 

Yep, looks real similar to my Cessna flap gauge...needle is in same
"resting" position, uses three input leads.

Test it out: put power to one lead (doesn't matter how much, everyting
is based off a ratio here...5vDC is fine), and ground the other two
leads. Try this with each lead and note the needle position. Ultimately
you will end up with one lead high or low at all times, and the other
two getting proportionate voltage such that the sum of voltage going to
each of the two "active" leads equals your logic voltage. Of course, in
our case it's not a variable voltage, it's PWM signals. So, your
Arduino outputs will look something like this (where 255 is maximum
Arduino setting for PWM output):

Vcc1: 0
Vcc2: 150
Vcc3: 105

Or perhaps:

Vcc1: 200
Vcc2: 55
Vcc3: 0

Another one:

Vcc1: 255
Vcc2: 0
Vcc3: 0

...and so on and so forth. Which pin you ground will determine what
area of the needle's range you'll have control over (as I recall it's
about a 70* sweep). Check the impedance between two pins and make sure
it's not going to harm the Arduino....mine did not need any resistors or
anything.

-- 
Matt Bailey

Keeping It Real:
Sabreliner 60 Flight Simulator
Serial # 306-61 - N1JX
http://sabrelinersim.com