How does the computer mouse work?

One of the indispensable components of any modern computer system is a computer mouse. This "rodent" has long been a part not only of personal computers, but also of laptops, although in a slightly modified form.

What a computer mouse looks like, everyone knows. To some extent, it does resemble a known agricultural pest, however, with a number of reservations. There is an opinion that this association will not be obvious to future generations of users. At least because the modern computer mouse is increasingly performed wireless, losing the "tail".

The principle of operation of this amazing device is extremely simple: when it moves around the surface, relative coordinates are transferred to the computer, where special software is converted into cursor-pointer movements on the screen. What is interesting, they can be not only the familiar arrow of the operating system, but also the character in the computer game. Behind apparent simplicity lies the work of engineers, electronics engineers and programmers. Depending on the design features, the computer mouse can differently register movements. Let's remember how these seemingly identical devices differ.

The first models, which appeared 50 years ago, were mechanical. Inside the device was a massive metal ball, covered with a layer of rubber. The lower side touched the outer surface, and the other two - with the rollers. There could be four, but only two were processed. When moving the hand holding the mouse, the ball rotation was transferred to the rollers, from them to the switches, and then it was transformed into a sequence of electrical signals sent to the computer. Two rollers are enough to get the coordinates of a point on a plane. The disadvantages of this solution include the need for periodic cleaning of the ball from the adhered mud (the hair was curled, dust accumulated) and the replacement of worn out components.

Soon they were replaced by opto-mechanical solutions. Outwardly everything remained unchanged, but the switches were abolished, giving way to a more reliable solution - an optocoupler. A "terrible" name hides a completely innocuous LED and an optical sensor, collectively called an optocoupler. Each roller was combined with a perforated wheel placed between the sensor and the diode. When rotating, the light stream was interrupted, which was recorded by the sensor and transmitted to the computer. Knowing the frequency of the change "window / wall", you could determine the speed of movement and direction.

In 1999, there appeared original computer mice, called optical mice, in which the mechanical method of recording movement was completely abandoned. The LED illuminates the surface under the mouse, and a primitive camera takes pictures with a certain frequency. The processor of the device processes them and on the basis of the obtained results makes a conclusion about the speed and direction of displacement. It remains only to transfer these data to the driver program.

Soon they were replaced by laser modifications. The processor became more productive, the accuracy of focusing increased, there were almost no "problem" surfaces on which the sensor does not work. The main difference from optical in another type of LED, which emits not in the visible, but in the infrared range. By the way, the most expensive computer mouse is laser. True, its high cost (more than 24 thousand dollars) is due primarily to the encrustation of precious stones, and not technical features.