Advice on choosing actuator...

[patniemeyer]

Criteria: small, fast, zero force / load required, cheap.

I'm planning to build a very simple robotic face and I am not sure what kind of actuators I should use.  I'd like the eyes to move back and forth about an inch but to be able to do so quickly (in under a second at least).  I also want to open and close a mouth at a rate comparable to human speech... maybe a couple of times a second over at least 1/2" gap.

I'm aware of motor driven linear actuators, but they seem large, slow, and expensive...  I'd need these to fit in a tight space.  I've also seen the Nitinol actuators, but those seem to require a lot of power and behave unpredictably...  My project will have to run on batteries.

Are there other options I should consider?

thanks,
Pat Niemeyer

[patniemeyer]

It looks like "micro linear servos" for RC planes might be the way to go... very cheap and small.  I'm looking for one with a long throw and then I need to figure out how to drive it.