What is the maximum velocity that could detect the optical sensor of a mouse?

I'm planning to do an anemometer passing a cilinder over the light and monitoring the velocity with software. Thanks in advance!

Clever idea!

The "maximum" depends on a lot of variables. First of, it's not just the sensor, but also the electronics and software that determine the rate and quality of data sampling. There isn't much you can do about that, I'm afraid, but you can always invest in a higher-quality mouse if a cheapie isn't cutting it. Next, the surface that the sensor is looking at is going to affect performance as well... Perhaps the cylinder is too smooth or uneven. This you can fix easily enough with sandpaper. In any case, this whole project is going to require testing and tweaking, but it's totally doable.

Anyway, to get back to your problem:

If the surface of cylinder is moving too fast for the mouse to read it, slow down the surface of the cylinder using gears. http://en.wikipedia.org/wiki/Gear_ratio Remember you can find the number of revolutions per minute on one gear as long as you know the speed of the other gear.