Practical No.- 2

PRACTICAL NO.- 2 Aim: Study of a pointing device called as mouse. Introduction: A mouse is a pointing device that functions by detecting twodimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a Graphical User Interface. The first marketed integrated mouse – shipped as a part of a computer and intended for personal computer navigation – came with the Xerox 8010 Star Information System in 1981. However, the mouse remained relatively obscure until the appearance of the Apple Macintosh; in 1984 a prominent PC columnist commented the release of this new computer with a mouse:

Traditional Mouse: The pointing device typically described as a “mouse” is a palm-sized plastic housing with a rubber ball protruding slightly from the bottom, and a cord coming out the back. This type of mouse works by having two rollers up against the rubber ball, one for x-axis and other for y-axis. As you move the mouse, the rubber ball rolls, turning the two rollers at the different rates, depending on the direction of the movement. The rollers are attached to the perforated disks that spin at the same rate as the rollers. On one side of each disk is an infrared light source, and on the other is an optical sensor. The sensors determine how far the mouse has moved on each axis by detecting the flashes of infrared light passing through the holes in the disks. The information gathered by the sensors is then transmitted to the computer, which translates it into relative movements of the cursor on the display. This type of mouse is also called an opto-mechanical mouse. In addition to ball, the mouse has a number of buttons on the back. The typical PC configuration calls for two buttons, but some mice have three, and the latest models have two buttons and a vertical wheel. Clicking the left mouse button selects the object on the display that is under the cursor. Other manipulations of the buttons, combined with mouse movements, perform other actions that are defined by the application or operating system currently in use.

The standard opto-mechanical mouse mechanism

Optical Mice: An optical mouse is an advanced computer pointing device that uses a light-emitting diode ( LED ), an optical sensor, and digital signal processing ( DSP ) in place of the traditional mouse ball and electromechanical transducer. Movement is detected by sensing changes in reflected light, rather than by interpreting the motion of a rolling sphere. The optical mouse takes microscopic snapshots of the working surface at a rate of more than 1,000 images per second. If the mouse is moved, the image changes. The tiniest irregularities in the surface can produce images good enough for the sensor and DSP to generate usable movement data. The best surfaces reflect but scatter light; an example is a blank sheet of white drawing paper. Some surfaces do not allow the sensor and DSP to function properly because the irregularities are too small to be detected. An example of a poor optical-mousing surface is unfrosted glass. In practice, an optical mouse does not need cleaning, because it has no moving parts. This all-electronic feature also eliminates mechanical fatigue and failure. If the device is used with the proper surface, sensing is more precise than is possible with any pointing device using the old electromechanical design. This is an asset in graphics applications, and it makes computer operation easier in general. Working Procedure: Developed by Agilent Technologies and introduced to the world in late 1999, the optical mouse actually uses a tiny camera to take 1,500 pictures every second. Able to work on almost any surface, the mouse has a small, red light-emitting diode (LED) that bounces light off that surface onto a complimentary metal-oxide semiconductor (CMOS) sensor. The CMOS sensor sends each image to a digital signal processor (DSP) for analysis. The DSP, operating at 18 MIPS (million instructions per second), is able to detect patterns in the images and see how those patterns have moved since the previous image. Based on the change in patterns over a sequence of images, the DSP determines how far the mouse has moved and sends the corresponding coordinates to the computer. The computer moves the cursor on the screen based on the coordinates received from the mouse. This happens hundreds of times each second, making the cursor appear to move very smoothly.

Optical Mouse with LED

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Optical mice have several benefits over wheeled mice: No moving parts means less wear and a lower chance of failure. There is no way for dirt to get inside the mouse and interfere with the tracking sensors. Increased tracking resolution means smoother response. They don't require a special surface, such as a mouse pad.

Cordless Mouse: Also known as wireless, cordless is the ability to operate a device without any wires that may cause constricted movement. Cordless computer hardware devices commonly utilize such Infrared or Bluetooth. Cordless networks, more commonly known as Wi-Fi, utilize one of the IEEE 802.11 wireless standards to achieve wireless. Although a cordless hardware device requires no wires, it will commonly require some type of device to broadcast a signal; for example, a Bluetooth mouse may require a USB Bluetooth transceiver to send and receive signals from the mouse. In addition to this, all wireless hardware devices will require batteries to power the device or utilize power from the computer.

Cordless (Wireless) Mouse Of Logitech

Intellimouse close-up image

Intellimouse: Also known as a wheel mouse or a scroll mouse, the IntelliMouse is a mouse developed by Microsoft in 1996 that has a wheel between the left and right mouse buttons that enables the user to easily scroll up and down using the wheel instead of having to use the vertical scroll bar. In addition to being able to scroll, these types of mice also have the ability to use the wheel as a button by pressing down on the wheel. An example of how this button could be used is users who are using Mozilla Firefox can use the middle-button (wheel) to open a link in a tab. The image to the right is an example of what the Microsoft IntelliMouse looks like. Because of the wide popularity and great functionality of this wheel, this type of mouse has become a standard mouse used with all new computers. Although "IntelliMouse" is a Microsoft Trademark, these types of mice are developed by numerous different companies today. Another popular manufacturer of these types of mice is Logitech.

Trackballs: Type of input device that looks like an upside-down mouse. The onscreen pointer is moved by the trackball with a thumb or finger. A trackball requires less arm and wrist motion that a regular mouse takes. To the right is a picture of the Logitech Cordless Trackman Optical and an example of a trackball mouse.

Trackball Mouse

Touchpad

Touch Pads: Also known as a glide point or track pad, a touchpad is an input device found on the majority of portable computers, and now also available with some external keyboards, that allows you to move the mouse cursor without the need of an external mouse. A touchpad is operated by using your finger and dragging it across a flat surface; as you move your finger on the surface, the mouse cursor will move in that same direction, and like most computer mice, the touchpad also has two buttons below the touch surface that enables you to click like a standard mouse.

Joystick: A peripheral input device that looks similar to a control device you would find on an arcade game at your local arcades. A computer joystick allows an individual to easily navigate an object in a game such as navigating a plane in a flight simulator. The image to the right of this text is an image of the Logitech Freedom 2.4 joystick and is an example of what you would expect most computer joysticks to look like.

Logitech Joystick

Pointing Device Interface Types: Pointing devices can connect to PCs in a number of different ways. The functionality of the devices is the same; they simply access the computer’s processor in different ways. The various interfaces are as follows:

Serial Port Connectors: A serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port). Throughout most of the history of personal computers, data transfer through serial ports connected the computer to devices such as terminals and various peripherals.

For networking, it has been replaced by Ethernet. While nearly every server has a serial port connector, most non-power user workstations and laptops do not have a outwardly wired one as it is a legacy port, and superseded for most uses. Serial ports are commonly still used in legacy applications such as industrial automation systems, scientific analysis, shop till systems and some industrial and consumer products. Serial ports are still used in these areas as they are simple, cheap and their console functions (RS-232) are highly standardized and widespread.

A male DE-9 connector used for a serial port on a PC style computer

Motherboard Connectors: One of the most important connections in the PC is that between the power supply and the motherboard. It is through this connection (or set of connections) that the various voltages and other signals are sent between these two important devices. (You may want to familiarize yourself with these signals in the section on power supply functions if necessary.) Different form factors use different numbers, types, shapes and sizes of connectors between the power supply and motherboard. Before we look at the connectors, let's talk a bit about the wires that run between the power supply and the connectors themselves. Pretty much all wires within the PC are made from copper, due to its excellent conductivity, relative low expense, and flexibility. The most important characteristic of a wire is its size, and more specifically, its cross-sectional area. The reason is that the resistance of the wire is inversely proportional to the cross-sectional area of the wire. Thicker wires can carry more current, while the higher resistance of small wires causes heating when they are subjected to a high current, which can be hazardous. Since some wires need to carry more power than others, they are given different thicknesses. In addition, most motherboard connectors have multiple wires for the main voltage levels. This allows for more current, spread out between the different wires.

USB Connectors: USB - Universal Serial Bus connectors are intermediateries for connections between Computers and Hardware. These USB connectors let you attach everything from mice to printers to your computer quickly and easily. Printers connected to parallel printer ports, and most computers only came with one. Things like Zip drives, which need a high speed connection into the computer, would use the parallel port as well, often with limited success and not much speed.The operating system supports USB as well, so the installation of the device drivers is quick and easy, too Anyone who has been around computers for more than two or three years knows the problem that the Universal Serial Bus is trying to solve in the past, connecting devices to computers has been a real headache.

The Universal Serial Bus gives you a single, standardized, easy to use way to connect up to 127 devices to a computer.. Most computers have at most two serial ports, and they are very slow in most cases. Devices that needed faster connections came with their own cards, which had to fit in a card slot inside the computer case.

Bus Connections: Modern field bus connections have to be easy to implement and extremely reliable. Adding to its I-Net product line, Provertha developed a Plug & Play bus connector for the CAN-BUS fulfilling these needs and addressing a broad range of applications in industrial communications and automation. CAN-BUS devices with D-Sub interfaces require an easy, fail-safe connection, and fault-free data transmission, as a faulty CAN-BUS connector can result in down times of complex industrial and factory automation systems with high related costs to follow. Provertha’s new bus connector Plug & Play CAN-BUS with two M12 connector interfaces uses 100% tested bus connectors, and 100% tested M12 cable assemblies, to secure a fast and fail-safe CAN-BUS connection. The new bus connector Plug & Play CAN-BUS allows the implementation of field bus components within seconds, as it needs neither a time-consuming cable preparation nor an often critical cable shield connection to the bus connector. The M12 connector comes with the standardized A-coding. As an additional benefit this Plug & Play CAN-BUS connector carries all of the signals specified in the CAN-BUS standard, i.e. CAN-Low, CAN-High, and CAN-GND, as well as the supply voltages V+ and V-. An external switch with its ON/OFF position visible from the front side can be used to activate the termination resistors for the bus termination. The connector is available without or with a second D-Sub as a PG interface for programming or diagnosis purposes.

Bus Connections

Mouse Troubleshooting: There are so many troubleshooting while using a mouse. Some important one are:  Sometimes the mouse is not working. It is not recognized by the system or the mouse drivers.  Sometimes the mouse is stuttering, sticking or moving in a jerky fashion.  Sometimes a PS/2-style mouse doesn't work on Serial Port when an adapter to convert it from the PS/2 6-pin mini-DIN connector to the 9-pin serial connector is used.  Sometimes the mouse works under Windows 95, and in DOS boxes running under Windows 95, but not when I boot to DOS or "Restart the computer in MS-DOS mode".  This section discusses troubleshooting of problems with mice or related to them. Like keyboards, mice are extremely simple devices that rarely fail and are relatively simple to troubleshoot. Since new mice can cost as little as ten dollars--even decent quality ones sometimes, believe it or not--they are in many ways items that you discard and replace when they stop working. Of course most problems with them are relatively straightforward to fix anyway. They are also easy to diagnose by swapping with another mouse.