timer relay/dc motor control

I am not sure if this belongs here, and I will do my best to describe the problem I am facing. I have a screen that i am mounting into a chassis to make it flip, I have the chassis all figured out and once installed it will need to move 120 degrees in about 2 seconds. It is going to rotate on a center axis and I felt it would be best to just use a dc motor, or a pair of dc motors geared appropriately. What I need is a way to activate it preferably with one switch. Here goes: My headunit (DNX7100) has an output to control an external device (it operates via a button on the touch screen) The output can be set for pulsed or constant and is good for 500ma. I either need: option a: when the switch is turned on and provides a constant output, a circuit that activates the motor to spin one way for 2 seconds (equaling 120 degrees of travel) and then when power is cut (switch is turned off) it the motor spins in the opposite direction. option b: same setup, but instead of a constant output, it operates ona pulsed output, i.e. on the first pulse it spins forward x distance, and on second pulse it spins the opposite way x distance. also, does anyone know a good place to find TImer relays? turning either a constant signal or pulsed signal into a timed duration pulse? (i.e. 2 seconds)

DEI has two possibilities, 528T and 611T.Prepare your future. It wasn't the lack of stones that killed the stone age.

whats the difference

The 611T can be latched on/off.  First pulse latches on and a second pulse on the same wire unlatches.Prepare your future. It wasn't the lack of stones that killed the stone age.