A mechanical mouse consists of a heavy rubber ball whose movement makes the cursor move on the screen. Commonly known as the ‘rolling rubber ball’ mouse, it is considerably heavy, thanks to the rubber ball, a few wheels, and a number of other mechanical parts present inside it.
When you move the mouse, the ball rolls beneath it, pushing the two plastic wheels/rollers linked to it in the process. One of those wheels detects side-to-side movement (x-axis wheel) and the other (y-axis wheel) detects movement in the up-and-down direction. Both of these wheels consist of spokes that ‘break’ a thin light beam inside the mouse. The number of times the beam breaks helps to calculate how far the mouse has moved. For instance, when you move the mouse straight up, the y-axis wheel turns. The farther up you go, the more the ball pushes the wheel and the more it breaks the light beam. This helps to determine how far the mouse has moved straight up.
Similarly, the mouse uses the x-axis wheel to calculate side-to-side movement. When the mouse is moved at an angle, the calculations obtained from the movement of both of these wheels are used. Mechanical mice were quite popular in the past decade, but due to their clunkier design and relatively lessened durability, they were quickly replaced by optical mice.
How does the Optical Mouse work?
An optical mouse is technologically much more advanced than a mechanical mouse. Unlike the latter, an optical mouse is completely electronic and therefore has no moving parts. It consists of an LED (that generates the signature red light), a light-detector chip, a switch mechanism and a few other simple components. Some mice have another LED that lights up a plastic strip installed at the back of the mouse as an indication of the mouse’s operation.
The LED installed at the bottom of the mouse emits a bright light in the downward direction. Since a mouse is usually used on plain surfaces, the light bounces back from the surface and enters a photocell that’s also mounted on the bottom, almost next to the LED. This photocell has a frontal lens that magnifies any light reaching it. As you move the mouse around, the pattern of the reflected beam changes; this is then used by the light-detector chip to figure out how and in which direction you’re moving the mouse.
Optical mice are much lighter and faster than mechanical ones, and have therefore gained enormous popularity all over the world.