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How a ball computer mouse works
Here's a closeup of the mechanism that allows an old-style ball mouse to detect your hand movements. There's a light beam running between the transparent square (an LED-style light emitter) and the black square (a photocell/light detector). As you move your hand, the mouse ball moves too. It pushes against a roller that turns the spoked wheel, breaking the light beam repeatedly. Counting the number of times the beam is broken gives a precise measurement of how far your hand has moved.
This photo is from our article on how computer mice work.
For a bit more context, see the photo of the same mouse taken from overhead.
Our images are published under a Creative Commons Licence (see opposite) and are free for noncommercial use. We also license our images for commercial use. Please contact us directly via our website for more details.
How a ball computer mouse works
Here's a closeup of the mechanism that allows an old-style ball mouse to detect your hand movements. There's a light beam running between the transparent square (an LED-style light emitter) and the black square (a photocell/light detector). As you move your hand, the mouse ball moves too. It pushes against a roller that turns the spoked wheel, breaking the light beam repeatedly. Counting the number of times the beam is broken gives a precise measurement of how far your hand has moved.
This photo is from our article on how computer mice work.
For a bit more context, see the photo of the same mouse taken from overhead.
Our images are published under a Creative Commons Licence (see opposite) and are free for noncommercial use. We also license our images for commercial use. Please contact us directly via our website for more details.