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How do ball style computer mouse works ?

By:Prayag Nao

A mouse is something you push along your desktop to make a cursor (pointing device) move on your screen. So what a mouse has to do is figure out how much you're moving your hand and in which direction. There are two main kinds of mice and they do this job in two different ways, either using a rolling rubber ball (in a ball-type mouse) or by bouncing a light off your desk (in an optical mouse).
i am going to explain how does a ball type mouse work.If you want read working of optical mouse read my post on.How do optical mouse works ?

Inside a ball-style computer mouse

Traditional mice have a rubber ball inside them. Open one up and you can see the heavy ball clearly and the spring that keeps it in position.

Here's the inside of an old-style Logitech ball mouse:

  1. Switch detects clicks of left mouse button.
  2. Switch for middle button.
  3. Switch for right button.
  4. Old-style connection to PS/2 socket on computer.
  5. Chip turns back-and-forth (analog) mouse movements into numeric (digital) signals computer can understand.
  6. X-axis wheel turns when you move mouse left and right.
  7. Y-axis wheel turns when you move mouse up and down.
  8. Heavy rubber wheel.
  9. Spring presses rubber ball firmly against X- and Y-axis wheels so they register movements properly.
  10. Electrolytic capacitor
  11. Resistors.

How a ball computer mouse works ?

How does a mouse like this actually work? As you move it across your desk, the ball rolls under its own weight and pushes against two plastic rollers linked to thin wheels (numbered 6 and 7 in the photo). One of the wheels detects movements in an up-and-down direction (like the y-axis on graph/chart paper); the other detects side-to-side movements (like the x-axis on graph paper).

How do the wheels measure your hand movements? As you move the mouse, the ball moves the rollers that turn one or both of the wheels. If you move the mouse straight up, only the y-axis wheel turns; if you move to the right, only the x-axis wheel turns. And if you move the mouse at an angle, the ball turns both wheels at once. Now here's the clever bit. Each wheel is made up of plastic spokes and, as it turns, the spokes repeatedly break a light beam. The more the wheel turns, the more times the beam is broken. So counting the number of times the beam is broken is a way of precisely measuring how far the wheel has turned and how far you've pushed the mouse. The counting and measuring is done by the microchip inside the mouse, which sends details down the cable to your computer. Software in your computer moves the cursor on your screen by a corresponding amount.

There are various problems with mice like this. They don't work on all surfaces. Ideally, you need a special mouse mat but, even if you have one, the rubber ball and its rollers gradually pick up dirt, so the x- and y-axis wheels turn erratically and make the pointer stutter across your screen. One solution is to keep taking your mouse to pieces and cleaning it; another option is to get yourself an optical mouse.



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