

If you have ever used a computer (and
you must be using a computer right now to be reading this), then you will
have used a mouse at least sometime in your life. In fact, mice are often
used in personal computers today! This is because the graphic user interface
that modern computers use relies hea
vily
on "pointing and clicking." We use mice to direct our cursor to
a certain point, and then we click on a button to select our choice (for example,
to click on an application we want to open, or to direct our cursor in a word
document to a certain sentence).
Courtesy of Clips Ahoy
The original mouse was invented by Doug Engelbart in 1967 at the Stanford Research Institute. It was the humongous- about the size of a baseball, and was called a "mouse" because its appearance closely resembled that of a mouse. It had large wheels on which it moved, and three control buttons. These buttons looked like a mouse's eyes and nose. In addition, Engelbart's mouse had a long cord, which looked like a mouse's tail!
How a mouse works:
2. Inside the mouse there are two rollers. In most mice, these rollers look like black bars. If you open up the disk on the bottom of the mouse and take the ball out, you will be able to see these rollers. One of the rollers detects the horizontal movement of the mouse, while the other detects the mouse's vertical movement. Working together, the two rollers can determine which direction the mouse is moving!
3. When the ball rolls, it causes the rollers to roll. When the rollers roll, they cause a special disk to spin. The disk is circular with rectangular holes spaced out along its outer edge.
4. On one side of the disk there is an infrared LED, while on the other side of the disk, opposite the LED, there is an infrared sensor. When the disk spins, the light from the LED can go through the rectangular holes periodically.
5. The sensor is able to sense these pulses of light.
6. A processor directly built into
the mouse converts these pulses into binary digits that the computer can
understand, and the information is transferred to the central processing
unit by through the mouse's cord.
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