First Computer Mouse
The first computer mouse was constructed in 1964. It was invented at Stanford University. The original design was made out of a block of wood. It had two perpendicular wheels on the bottom to register motion in both directions. It meant that in whichever direction one drags the mouse, it was dragging one of the wheels sideways, which meant probably it wasn’t very smooth.
Then various types of mouses were invented, one of them was a Tandy mouse. This mouse was developed in the 1980s. Inside the Tandy mouse, a stainless steel ball was used. The ball was quite heavy so that it could make good friction with the surface. And two rollers were used inside the mouse to move it in x and y directions. And these rollers were connected to potentiometers. But the design was not that much suitable. Because at some point the rollers would stop moving.
Now taking a step ahead in the evolution of the mouse, the next mouse had a steel ball that was coated with rubber. So, it had enough weight but the surface had more friction. And this design of the mouse also consisted of rollers but they were not connected to potentiometers. On the sides of the rollers, optical sensors were used. The sensors were used to detect the presence or absence of light. So, this sort of mouses was known as an optomechanical mouse, because it incorporates optics and it is also mechanical. But one of the biggest problems with these mouses was that, if dirt gets accumulated then the rollers and the ball wouldn’t work properly. And most people didn’t have an idea of how to clean the mouse.
Then came the optical mouse. These mouses were sold for PCs and for Sun workshops. These mice required a special type of mouse pad. It was a grilled pad. In the backside of the mouse two lenses could be seen. While operating one of the lenses would lit up. The pad was designed with horizontal and vertical reflective lines. The vertical lines were only reflective of infrared rays. And The horizontal lines were reflective of red light. So the mouse consisted of two LEDs one red and the other infrared and both of them are facing downwards i.e towards the pad. It has two identical lenses. It also consists of one horizontal and one vertical sensor. They are designed to pick up light in the form of a line, and they are turned perpendicular to each other. And it also consisted of two mirrors that reflected the light from LEDs to sensors.
Now, let’s move forward to modern optical mouses. These mouses have a camera that looks at the surface. It consists of a sensor. It has an LED that lights up the surface. It also has a micro-controller. The job of the micro-controller is to read the movement information from the sensor and also to read the status of the buttons and scroll wheel. And then it converts the data into a PS/2 compatible data stream. In older mice, 2 chips were used for the purpose but in modern mouse, these two chips have been combined into a single chip to reduce the cost of the mouse.
To operate the Bluetooth mouse radio waves are used, as radio waves can easily penetrate through solid objects. Whenever the mouse provides some information, it is sent to the desktop in an encrypted form. And the desktop then decrypts the information into suitable data. And for these type of mouse Frequency Hopping Spread Spectrum technology is used.