Here is a link to the 12 VDC, 10 Amp linear actuator made by firgelli auto that I am referring to ...http://www.firgelliauto.com/product_info.php?cPath=69&products_id=248
I believe it just uses a servo motor. Correct me if I am wrong, but I was reading something yesterday that said I could use some sort of relay and transistors that could convert the 5V from the arduino to 12V needed by the actuator. Is this true or would I need a separate power supply for each one?
Actually the simplest way to control that is with a DPDT relay such that you just apply 12vdc to the motor wires with the polarity you wish to move, when the actuator reaches it's end of travel built in limit switches cut off the motor until you reverse the polarity of the applied voltage where it will then move in the opposite direction until it reaches the other end of travel and is stopped by the other built in limit switch. However if you wish to be able to command the actuator to move to a specific position and stop you are going to need a 10+ amp H-drive motor driver and some kind of analog feedback sensor so your arduino can tell where the actuator position is at any given time, and of course the software code to make that all work.
So as a minimum you would need a:
5 volt coil DPDT relay with contact ratings higher then 10 amps.
A transistor to switch the relay coil on or off
A resistor to wire between an arduino output pin and the base or gate of the transistor.