How does an optical mouse’s sensor know you’re moving it a certain direction?
In: 5
It’s got a little camera that looks at the surface texture, basically.
Try it on a clean mirror and it won’t work very well.
By checking where surface under mouse moves. Surface must be rough to properly detect movement.
This movement is checked usually many thousands times per second.
This sensor is a camera that takes pictures with amazing speed. If you take picture A and then picture B after 0.01 sec and compare them, they’ll have some common part. This part’s offset will be equal to the mouse offset.
Imagine a flipbook with the same shape on every page, but on different positions. You can tell that the shape is moving and determine direction by looking at static pictures.
I think other answers haven’t tried to explain yet – what we might commonly perceive as a regular surface texture can in fact by incredibly detailed and different at the levels at which the optical sensor is working.
I might see a uniform grey desk surface but there’s enough surface texture and differences in how light reflects from it (especially when using a laser light source) that two parts of my desk 1mm (and less) apart look vastly different from the mouse sensor’s perceptive.
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