Extend optical mouse range

Hi all,

I'm wanting to make a jig for a production project requiring a sensitive optical measure of movement with a focal length of 5-10 mm. I thought an optical mouse might be a good start but the lenses in a few I've tried require the device to be too close. It needs to be no bigger than the electronics of a mouse. If anyone has a lens that could be perfect or other ideas I'd love to hear them.

Thanks,
D

The problem you'll have is the very small size of the lenses you'll need. If you can find some tiny concave lenses, they'll extend your focus range
Would a disposable contact lens work?
Dunno. From my last [ahem] Contact with them, they are a bit too big. I'm thinking around 3mm (1/8") diameter.