12V Linear Actuator to control GPS Unit In Car Dash

[eman]

I would would like to build a contraption for my car that
will allow me to raise or lower a GPS navigator unit from the top center of my dash.

I want the simplest design possible (just one actuator, no servos or gears outside the actuator), so I am going to purchase a Firgelli L12 Mini Actuator.

I need about a 4" (~100mm) stroke.

I would like to unit to operate as follows:
#1 Key turned to accessory - unit extends on 12V
#2 Key turned off - units retracts, once retracted it must not draw any current from the battery.

Q:
What other electronic component do I need to accomplish #2? Im not sure what to tap into to get 12V reverse polarity when the key is turned to the off position and then removed from the ignition.

Also, what is the exact model of the L12 I would need. (Note: I want the Option S).

I have attached a sample picture of what I am referring to, except I want a 180 degree push and pull on the GPS, not a flip motion like the one pictured.

Thank You.


Eman

[Casmat]

It seems to us that the system could be done with a relay and perhaps two DPDT switches but we are not sure on the implementation yet. We will post a more definitive answer shortly..

This linear actuator seems appropriate for you: RB-Fir-78

[eman]

Thanks. I was hoping to get more replies. I will look into the relays, but don't imagine I need two. Any additional feedback is appreciated.

[Casmat]

After some thought, we determined the best approach would be to use a microcontroller or latching relays in order to achieve the functionality you describe, but you will need to program your own logic.

[Cbenson]

We really don't suggest playing with your ignition system unless you are confident you know what you are doing. Without power, the actuator will not retract, so you'd need a secondary battery, or plug the controller directly to the car's battery. Even powered, the system would need to "know" to take some action. By far the easiest approach would be to start with a DPDT switch (manual), then add a microcontroller.

[eman]

Thanks for the advice. The reason I don't want a manual switch is because there may be times I will forget to retract the GPS which will leave it visible for potential thieves. I live in an urban city and I don't want my car broken into for a $150 GPS.
The Arduino seems like an interesting option and tempting because I am a software programmer. I will instead go with another device PAC-TR7 which will do what I need.

Again, thank you.