Simple Electric-Mechanical Device

ectric, voltage, I have a gate which I need to control (open & close) by direct (screw?) drive, 9 volt dc.

V_o = 0-1v = closed positon

V_A = 1-3v = pos #1

V_B = 3-6v = pos #2

V_c = 6-9v = pos #3

What I need is for the gate to close and open to which ever value range the supply is generating (ie; pos#1, #2 ,#3 or closed). The values are all arbitrary but close. The application would fall into something like the 'novelty' category. I am concerned with size, durability (outdoors) and of course...cost.

The load on the motor is nil as gate is ~14g. Is there a common circuit for this? Is there a specific motor type for this?

Thanks in advance. Oh, knowers of such things!