Project that electronically opens and closes 1/4" hole in very small area.
What would work ? A solenoid ? A 2 step step motor ? Anything else?
Thanks for any help

 

In what way should it close the hole?

 

Hi,

Have a small motor run a shutter back and forth.

 

You'll probably have to decide that for yourself; here are two more ideas: a solenoid operated blade that covers & uncovers the hole; a motor & gearbox that rotates a butterfly to do the same.

 

If the "very small area" is big enough for a half-inch diameter shutter, a regular old motor could turn the thing.