The purpose for it is to make my robot's eyelids blink.
I'm currently using a 6mm stroke mini solenoid but the eye lids needs to move 1 inch upwards and downwards.
I need a solenoid that has a stroke of at least 1 inch.
Where can I buy one which isn't as big as my hand? It's got to fit behind the eye of my robot which is about normal human size.
Normal eyelids aren't 1".
The average eye ball is a little less than an inch in diameter - closer to 24mm, and the eye lid doesn't cover the full diameter.
Even if it did, your 6mm solenoid may be quite fine, if it's strong enough (but with a balanced mechanical setup it should be), as you can just "lever it up".
Where S is the solenoid "attack point", o is the pivot point and E is where the eyelid goes.
I'm not sure what you mean by "a definite amount of space for the solenoid", as this will always be the case