Home Ch: 2 - Computers Input Devices
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Chapter 2 - Hardware and Software

Input Devices

The following are different devices to input data into your computer.

Keyboard. A keyboard is the primary device used to input data into a computer. The pressing of a key on a keyboard produces an electrical signal to the processor that converts the signal into digital data such as the letter A or number 4. There are many different configurations of keyboards with many different layouts. Keyboards can have trackballs, touchpads, or even scanners built in.

Mouse. A mouse is a device used to point to and select items on a screen. It is similar in appearance to a real mouse with a tail, as it is moved the cursor on the screen moves. It is used primarily on Graphical User Interfaces (GUI), and generally has two buttons that are pressed to activate commands. It also has a wheel in-between the two mouse buttons that when spun allows you to move documents and web sites up and down without moving the mouse.  It rolls on a rubber ball that translates the movement into input signals that the computer reads. A pointing device or mouse type device is a must with Windows-based applications.


Trackball. A trackball is a close relative of the mouse, and has the ball mounted in a permanent position on top. It is an upside down mouse. When you move the ball the cursor on your computer will move. It also has buttons to press to activate commands on the computer screen. They are generally used in small areas where space to move a mouse is unavailable such as on a laptop. They may be valuable in a courtroom or other setting where space is unavailable.

Touchpad. A touchpadis another relative of the mouse, and is a small smooth surface where a finger can be placed and moved to control the cursor on a computer screen. Tapping the touchpad once or twice will act as a “button” to activate computer commands.

Joystick. The joystick is also an input device used to control on-screen object movement. They are generally used for game software to control a plane in flight simulation, spaceships or characters in adventure games. Buttons on the sides allow the user to activate computer commands.

Scanners. Scanners are used to scan a piece of paper or graphic into digital data that a computer can read. Once in the computer, one can view the “electronic picture or graphic” and edit the image. These electronic images can be stored or printed. The two most popular scanners are flatbed and hand-held scanners. Also, with a scanner you can scan paper and use Optical Character Recognition (OCR) software to convert the words on paper to ASCII readable text. Then, this ASCII text from briefs or interrogatories can be imported into your word processing for changes. A high quality scanner can be purchased for $150 - $350. Options to consider are multiple paper feeder trays, DPI, (dots per inch rate – the higher the dpi the sharper the imaged document), color scanning capability, image formats supported by the scanning software, whether OCR and image editing software is included, and scalability to larger systems.

Graphics tablet. A graphics tablet is a special input device that has a soft tablet and a pen or stylus to draw on it. When a stylus is pressed on the tablet, the tablet converts the exact image drawn onto the computer screen where it can be edited. They are generally used with graphics programs. They can be used to draw on documents and other exhibits for courtroom presentations.

Pen Computing is using a pen or pointing device to write or perform other functions on a computer screen. This developing technology enables a person to use a pen, similar to a pen and yellow pad, and write on a computer screen that is usually horizontal. The writing will be converted into ASCII text. They are generally used today to fill in forms by checking boxes since the accuracy of converting actual handwriting may be problematic.

Digital Camcorders and Cameras are recent new input devices that enable one to take photos or digital video, and then easily download or transfer them directly into a computer from the camera.

Digital camcorders can act as a camcorder or as a still camera. The camcorder can record full motion video in MPEG-1 video format with sound along with JPEG photographs. You can take up to 5,400 still shots on one tape.

With digital cameras there is no more waiting for film development or photo scanning. Still, digital camera buying considerations include resolution quality, color, memory, number of pictures, LCD display availability, flash, type of storage, focus free and zoom, self-timer, and whether software is bundled with the camera.

To capture still pictures from a VCR, TV, etc., consider the Snappy™ product. Just plug the Snappy™ hardware module into your PC or laptop parallel port. Then connect any camcorder, VCR or TV with the included cable. Watch your PC screen and when you see a picture you want, click SNAP.


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