I'm searching for the smallest possible linear actuator which will meet my requirements:
~ 3.5 mm displacement & ~ 10N force
It's for a haptic feedback device, but to get a better idea of what I'm looking for, imagine something which is just strong enough and has just enough travel to push down a key on a chiclet keyboard. Its probably also fine if its a bit smaller.
All I seem to find are piezo-micro actuators, which usually do not have enough force or displacement, or actuators which are way overkill for my application. I could probably use one of the micro servos people use on model planes, like this one: http://2bfly.com/assets/ElectriflyMicroLinear1.png
I'm curious to see if anyone knows of any other options.
There was a link posted on this forum a few months ago, to an ebay listing with really tiny linear screw actuators. I don't know about 10N but they would probably go close.
I can't find the original posting. (I did find at least one other project similar to yours.) But I bought some of them so I have the original link from ebay.
You are unlikely to find something much smaller as torque depends on motor volume. Its rather
specialised kind of motor - perhaps look for old floppy disc drives, the linear drive in those is
a fair bit chunkier than modern DVD drive hardware.