Portfolio(mouse) - investigation on computer mouse PDF

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A significant invention -computer mouse

Introduction: Nowadays, most people work with computers and use mouse to control the cursor on the computer to do things they want. It is very efficient because people can get access to anything on the computer easily. However, in the 1960s, the development of computer technology was in a primitive stage. It was hard to operate the computer because all the commands could only be inputted by typing on the keyboard even to move the cursor slightly. In 1964, Douglas Carl Engelbart (1925-2013), an American engineer working at Xerox PARC, invented the first mouse which was known as the X-Y Position Indicator.[2] The mouse consisted of a woolen box with two metal wheels in it which made the contact with the surface, as well as one button on it. (See Fig.1 and Fig.2)

Figure 1[3]

Figure 2[4]

The working principle of this mouse was: when moving the mouse, the pivot was rotated, and the resistance of a rheostat was changed to produce a displacement signal that can be processed by the computer to move the cursor on the screen.[5] The invention of the computer mouse was a significant breakthrough which simplified the operation of the computer and laid a foundation for the future development of computer input and control technologies. Why is it called mouse? Somebody thought it was short for “manually-operated userselect equipment”. However, when Douglas Carl Engelbart inventing the mouse, he named it mouse just because it looked like a rodent.[2] Computer mouse is now known as a hand-operated input device that is used to control

the cursor on the computer.[2] Most mice have two buttons and a mouse wheel, they are not big and can be easily controlled. (See Fig.3)

Figure 3[2]

History: After the first mouse invented in 1964 by Douglas Carl Engelbart, there were many companies (such as Xerox, Apple, Microsoft, and Logitech) started to pour millions of money to develop the form and the function of the mouse. They changed the number of buttons on the mouse, the interfaces by which mice connect to computers, and put forward new methods of tracking movement.[6] In 1972, Jack Hawley and Bill English design a digital mouse for Xerox PARC. This new mouse can directly send digital positional information to the computer instead of using an analog-to-digital converter.[6] It also used a metal ball to replace the two wheels, which allowed the mouse to move in every direction, so this mouse was also known as “Ball Mouse”.[1] In 1981, Xerox invented a commercial mouse for its Xerox Star 8010 Information System, which featured two buttons and a tracking ball. However, the Star 8010 system was sold for over $20,000, which doomed it and so the mouse was obscured. By contract, a design company called Hovey-Kelley created the first cheap, reliable and mass-producible mouse for Apple. Its main components included optical encoder wheels, a free-moving tracking ball, and a precise injection-molded inner frame. This design breakthrough made computer mice become reliable and cheap so that everyone can afford them.[6] In 1991, Logitech launched the world’s first cordless mouse that used radio frequency transmission, the Cordless MouseMan. Unlike infrared cordless devices, the mouse invented by Logitech did not need line-of-sight with a base station to work. [6] In 1993, Honeywell found a new mouse tracking way with its Opto-Mechanical mouse. Instead of using a rolling ball, the mouse used two small angled discs on its bottom to track its motion. [6]

In1996, Microsoft introduced the mouse with a scroll wheel when it released the IntelliMouse Explorer. It featured a rubberized plastic wheel between the two mouse buttons, which can also be pressed like a button. It was easy to scroll the screen or do some other functions by rotating the wheel.[6] In 1998, Apple's first computer mouse that supported the USB peripheral standard was born. The round shape of the mouse confused many users, and a nickname “Hockey Puck” was given to it.[1][6] In 1999, Microsoft released its first radio frequency wireless mouse, the Cordless Wheel Mouse, which marked the start of a new wireless trend. Then, other companies started to follow suit with it and produced the new generation of more exact and battery-save wireless mice, so the photoelectric mouse become more popular.[6] In 2003, Apple pushed out its first wireless mouse, named the Apple Wireless Mouse. It used Bluetooth as the wireless protocol, but it still had only one button.[6] In 2004, Logitech launched the first mouse that can use laser to track the movement, the MX 1000. The laser tracking technic that was developed by Agilent, provide d higher accuracy than former optical tracking system based on LED.[6] In 2009, Logitech launched Logitech M905 which used “DarkField” laser tracking technology. The technology used laser recognition and Darkfield microscope technology to allow the mouse to identify small flaws, dust, particles and other tiny materials in transparent materials in order to provide better feedback of location information.[7] In 2010, Microsoft released the bendable computer mouse. When it was not used, it can be laid straightly. When it was used, it can be bent to adapt to the user's palm shape. With the Blu-Ray technology, it allowed the mouse to be used on carpet or wood.[1]

Theory: DPI (dots per inch) is an index to show the sensitivity of the mouse. The higher a mouse’s DPI, the farther the cursor on the screen will move when you move the mouse. A mouse with a higher DPI can detect and react to slight movements better.[12] For example, when the mouse is moved 1 inch to the left, the 400 DPI mouse sends a "left" signal 400 times to the computer, while the 800 DPI mouse sends a "left" signal 800 times. If the mouse is moved 1/800 inch, the 800 DPI mouse will send one movement signal to the computer, while the 400 DPI mouse will not respond to the movement. It must be moved another 1/800 inch for it to send a movement signal. Therefore, the higher the DPI of a mouse, the higher the sensitivity it is. Mechanical mouse and optical mouse were the two widest used mice in the past. The structures and working principles of the two types of mouse are different. (See Fig.4)

Figure 4[8]

Mechanical mouse The main structure of a mechanical mouse consists of a rolling ball, two perpendicular rollers next to the ball, two LED emitter, two sensors and an encoding disk. (See Fig.5) When the mouse is moved, it will drive the rolling ball to turn, and the two rollers will also be driven to turn. The photoelectric pulse signal was generated by the infrared LEDs at the end of the rollers and was gathered by the sensor that reflects the displacement change of the mouse in the vertical and horizontal directions, and then controls the movement of the cursor on the screen through the processing and transformation by the computer program. Instead of having two round wheels at the bottom that are perpendicular to each other, it has a small synthetic resin ball that can roll in every direction. When the ball is rolling, it drives the x and y rollers at the same time. At the end of the roller, there is a round decoding wheel. On the decoding wheel, there is a metal conductive plate directly contact with the electric brush. If the rotating shaft turns, these metal conductive plates and the brush will contact one by one and appear in the form of "on" or "off". The former corresponds to the binary number "1" and the latter to the binary number "0". These binary signals are then sent to the computer to analyse and generate the signal of the change of the coordinate of the mouse. As long as the mouse moves, the ball will drive the two rollers to rotate, which will change the on and off situation of the decoding wheel and generate groups of different coordinate of the mouse, which will be reflected as the cursor can move with the mouse.[10]

1. The movement of the ball 2. X and Y rollers 3. Optical encoding disks including light holes. 4. Infrared LEDs emitter 5. Sensors that gather the light pulses.

Figure 5[9] There are two physical theories that is used in the mechanical mouse. Firstly, the friction was the key to the rotation of the ball and the two rollers. When the mouse is moving on the floor, the friction that the floor gives to the ball makes the ball rotate, which also leads to the rollers also start to rotate because of the friction given by the ball. Instead of a glass ball, the surface of the rolling ball is synthetic resin which can produce a higher friction and is more sensitive to the movement of the mouse. Secondly, the optical sensor was used to detect and analyze the light emitted by the LED. It can transfer the light signal to electrical signal which can be processed by the computer program. The faster the mouse moves, the faster the ball rolls, and the more pulses the sensor gathers per unit time, the faster the cursor moves. The distance that the ball rolls reflects the number of pulses of the light which can be used to calculate the distance that the mouse traveled. For example, the diameter of the rolling ball is 21mm, the diameter of the two rollers is 7mm, there are 36 holes on the encoding disk, if the mouse moves 25.4mm, the sensor will detect 41 light pulses which will be transferred to the computer through USB or PS/2 connector, and then the computer will know the movement of the mouse and send command to move the cursor.[13] Therefore, to make the DPI of the mouse higher, the diameter of the rolling ball and the encoding disks, as well as the number of holes on the encoding disk can be increased.

Optical mouse The internal structure of optical mouse consists of a diode, a light pipe, an optical mouse sensor and a microchip. (See Fig.6) Inside the photoelectric mouse is a diode that can emits light and illuminates the bottom floor of the mouse. A part of the light is reflected from the bottom floor is transmitted through a set of optical lenses to an optical mouse sensor for imaging. In this way, when the photoelectric mouse moves, its movement track will be recorded as a set of high-speed coherent images, which will be analyzed and processed by a

chip called digital signal processor (DSP) inside the mouse. By analyzing the changes of the position of the feature points on these images, the chip can determine the direction and distance of the movement of the mouse and then give the feedback to computer. The computer program will then transfer the data to the signal of the movement of the cursor so as to move the cursor.[10]

Figure 6[11] There are two physical theories was used in the optical mouse. Firstly, the reflection of the light was used. The LED light (normally red light) emitted by the diode is reflected 3 times and finally collected by an optical sensor, the first and the second reflection happens in the lens pipe, the third reflection happens on the floor. Secondly, an optical lens is placed below the sensor, the image of the illuminated bottom of the mouse can be transmitted to a hole in the bottom of the optical sensor through it. Nowadays, instead of mechanical mouse, people are more likely to use optical mice. There are several reasons to explain why optical mouse is better than mechanical mouse. Firstly, the scanning accuracy of the traditional mechanical mouse is generally below 800 DPI, while the photoelectric mouse can reach 1600 or even 4000 DPI, which is the main reason why the photoelectric mouse can easily surpass the mechanical mouse in the positioning accuracy.[13] Secondly, there is no moving parts inside the optical mouse, which means it would have less wear and lower chance of malfunction.[13] Thirdly, the dust or dirt are hard to get inside the optical mouse to interfere the optical sensor, so the optical mouse is more accurate.[13]

Conclusion: Computer mouse plays an important role in the operation of computer, it simplifies the operation to move the cursor, which makes computer can be easily used by people. Physics theories are used in the mouse to make it works. For example, mechanical mouse is an application of friction, optical mouse is an application of light. Different kinds of computer mice have different working principles and the physical theories behind it. Nowadays, people have invented some novel mice such as 3D vibrating mouse, Bluetooth mouse and so on based on physics. The development of the computer mouse is still ongoing, people are trying to make the mouse more durable and can move more accurately. More physical theories will contribute to the development of computer mouse, as the saying goes “Physics makes the world better”.

References: [1] The history of computer mouse https://www.sutori.com/story/history-of-computer-mouse--2yUFPn6vNQBstaaz2x4FTdsy [2] Introduction of computer mouse https://www.computerhope.com/jargon/m/mouse.htm [3] Figure 1 https://time.com/3831359/computer-mouse-history/ [4] Figure 2 https://www.quora.com/When-was-the-computer-mouse-first-used [5] Information about the first mouse http://www.dougengelbart.org/content/view/162/000/ [6] The history of computer mouse https://www.macworld.com/article/1137400/mouse40.html

[7] Logitech Darkfield Laser Tracking Technic https://www.logitech.com/images/pdf/briefs/Logitech_Darkfield_Innovation_Brief_2009.pdf [8] Figure 4 https://www.britannica.com/technology/input-output-device [9] Figure 5 https://en.wikipedia.org/wiki/Computer_mouse#Mechanical_mice

[10] The working principle of different kinds of mice https://www.explainthatstuff.com/computermouse.html [11] Figure 6 https://www.researchgate.net/figure/Structure-of-optical-mouse-sensor_fig1_221644902 [12] Explanation to DPI https://www.howtogeek.com/182702/mouse-dpi-and-polling-rates-explained-do-they-matterfor-gaming/ [13] The internal structure of different kinds of mice https://computer.howstuffworks.com/mouse.htm/printable...