Integrating real parts - Piper Cherokee Primer

[slocs]

Guys, I'm after some assistance if possible.  I read many years ago that integrating real parts into a sim enhances the level of immersion.

I'm in the process of building a PA28 Cherokee sim, partly to learn about integration before I start work on a 737-800 sim, and partly so I can maintain a level of IFR proficiency before I actually spend time in the real aircraft.

I've been collecting some parts for the sim, comprising a real switch panel, parking brake, flap lever (Johnson Bar), and Primer knob.  All the parts will be integrated via a Leo Bodnar card, and combined with Project Magenta GAIFR, some other components (12v Hobbs type gauge, volt meter etc) and a couple of USB gauges (manifold pressure and tacho).  Radios, throttles, yoke, and rudder pedals are all via Saitek.

Now to my question.  The majority of the real parts integrate nicely into the Bodnar card via switches, however I can't figure out a good way of enabling the primer knob.  I've attached a pic of the knob, which essentially sucks and blows fuel through the two fittings when the primer is pulled in and out.  I was thinking of some sort of air operated switch, but I can't seem to google an easy solution.

Can the brains trust here come up with some alternate ideas?

Many thanks,

Rob

[TomAnderson]

Hello Rob,
   This may sound crazy. You may can use a vacuum sensor off of a vehicle, maybe from the  cruise control.
   The idea would be that as the primer knob sucks, the sensor would change ohms or voltage.
Your local salvage yard may have something and it should be 12volts.

I am very new to this so I have no knowledge of how to interface it with the computer. 

[fsaviator]

 

http://s274.photobucket.com/user/wsoeldner/slideshow/Cherokee%20235%20Sim

I miss my Cherokee 235...  this was my second simpit.  The GNS was a labor of love.

[jackpilot]

Is the primer modeled by FS/ PM/your flight model ??

If yes , a slider could help.
http://www.phidgets.com/products.php?product_id=1112

Jack

[slocs]

Thanks for the quick responses guys.

Jack - good question about the primer being modeled.  The control is modeled in the virtual cockpit, but I suspect nothing else happens when it's activated!  This could all be a moot question - some more investigation is required!

fsaviator, Warren - your 235 cockpit has given me lots of ideas.  I flew a 1969 235 a year or so ago - 135 knots, no gear to worry about forgetting to extend, and just a little tricky in the flare (I was told it was because of the non-tapered wing)

Tom - great idea.  I hadn't thought of a vacuum switch, and ebay has yielded a couple of options, including:  http://www.ebay.com/itm/Micro-Pneumatic-Logic-Low-Pressure-Momentary-Switch-MPL503-MPL-Vacuum-Sensor-/121264515927?pt=LH_DefaultDomain_0&hash=item1c3bedab57



Thanks again guys,

Regards

Rob

[fsaviator]

No problem.

I have the frontpanel express files for the panel if you ever want them.

I bought vernier throttle/mixture/prop from aircraftspruce and mounted them to slide pots.
I made some of my own gauges, and used simkits for the rest
the glareshield I made out of pleather

I did use some creative license on mine as I also was a part owner of a Comanche at the time and had retractable gear in this one.

I used the DF Archer as the model