The joystick is also a pointing device like the mouse, which consists of a stick that pivots on a spherical ball on its base. A joystick is similar to a mouse excepts that the moment of cursor on screen stops working as soon as user stop moving the mouse. But with a joystick, the pointer continuous moving in the previously pointing direction. Commonly, joysticks are used for playing computer games like flight simulators but occasionally used for CAD/CAM systems and other applications.
Some joysticks also have a third degree of freedom i.e. the stick can be twisted in clockwise or anti-clockwise direction.
(iii) Light Pen
A light pen is a pointing device shaped like a pen and is connected to a Visual Display Unit
The tip of the light pen contains a light- sensitive element which, when placed against the screen, detects the light from the screen enabling the computer to identify the location of the tip of pen on screen.
(iv) Graphics Tablet
A graphics tablet (or digitizers, digitising tablet, tough tablets or simply tablet) is an input device that consists of an electronic writing area and a special pen that works with it. It allows artists to create hand-made images and graphical images with motion and action, similar to the way a person draws images with pencil and paper.
The pen of the graphics tablet is pressure sensitive, so pressing harder or softer can result in brush strokes of different width.
(vi) Touchpad (Track pad)
When user draws anything on the tablet with the special pen, the drawing appears on the screen.
The tablet and pen can also be used like a mouse to move the cursor and click. Graphics tablet may also be used to capture data or handwritten signatures.
(v) Touch Screen
It is an electronic visual display that can detect the presence and location of a touch within the display area. The term touch screen \Touch scre generally refers to touching the display of the device with a finger or hand. The touch screen sends a signal to the computer. This signal gives the location on the screen, which has been touched. Touch screen is quick and simple to use. Generally, smart phones have a high-resolution capacitive touch screen. There are different types of touch screens available with electronic devices like capacitive touch screen, resistive touch screen and gorilla glass touch screen, etc.
Touch screen is pressure sensitive and activated by finger or stylus. Touch screen works as:
- Touch! Sensor It is a clear glass panel with a touch responsive surface.
- Controller A small PC card that translates information that PC can understand.
- Software Driver It allows to work with Existing software.
(vi) Touchpad Trackball
It is a specialised surface that can translate the motion and position of a user’s finger to a relative position on the screen. This is a common feature of laptop computers and also used as a substitute of a computer mouse, where disk space is scarce. The sensors of touchpad only react through fingertip and not a pencil or other object.
There are usually two buttons next to the touchpad which works as left and right button of the mouse.
It is designed for computers; generally serves as mouse replace ment. It is primarily used to move the cursor on the screen. The trackball has a ball on its top. Trackball can be rolled with fingers and the internal rollers sense the motion, which is transmitted to the computer. Trackballs are common on CAD workstations and sometimes seen on Computerized special purpose work stations, such as the radar consoles in an air-traffic control room or sonar equipment on a ship or submarine.
It is a device that allows a user to take an image or text – / and convert it into a digital file, allowing the computer to
read or display the scanned Scanner object. Scanners can be used for storing the documents in their original form that can be modified and manipulated later on. It is mainly used to convert a scanned document in a digital format.
Scanners come in a variety of sizes from hand-held models to desktop models as discussed below:
(i) Hand-held Scanners They are very small which can be held in a hand. These are less expensive and less wide. Hence, in order to scan a single page image, multiple passes are required. But their handliness is a major advantage of hand-held scanner.
(ii) Flatbed Scanners They are large and more expensive scanners that creates higher quality images. These scanners have a flat surface on which the printed image to be scanned, is placed. (Similar to the way a page is placed on a photocopier). Flatbed scanners can scan a page in a single pass.
(iii) Drum Scanners They are medium size scanners with a rolling drum. The sheet is fed through the scanners so that the drum rolls over the entire sheet to be scanned (Just as the sheets are fed in a fax machine).
(Magnetic Ink Character Recognition)
It is a character recognition technology which is primarily used by the banking industry to facilitate the processing of cheques. This technology allows the computers to read information (such as account numbers) on printed documents. Characters are printed in special typefaces with a magnetic ink (that contains Iron Oxide).
MICR can read up to 2400 documents/mm. The MICR coding system contains 14 characters (four special symbols and 10 decimal digits). So, it can recognize these 14 characters only. The type font E- 13 B, a standard typographical style, is used to print the characters or identification marks.
(Optical Character Recognition)
It is used to translate scanned images of handwritten, type-written, printed text or special type font printed on conventional paper with conventional ink into machine- encoded text.
It is widely used to convert books and documents into electronic files, to computerize a record-keeping system in an office or to publish the text on a website.
An optical reader uses photoelectric devices to scan the characters being read and convert the reflected light patterns of the data into binary data suitable for computer input.
The normal speed of an OCR is 1500 to 3000 characters per second.
The technology is being developed for greater accurate recognition and is also known as Intelligent Character Recognition (ICR).
OMR (Optical Mark Reader)
It is used to capture human marked data from document form such as surveys and tests.
One of the most familiar applications of optical mark reader is the checking of optical answer sheets in multiple choice questions:
It uses high intensity to read the marks or symbols. Optical mark reader
It is an input device used for reading printed bar codes (Universal Product Code) available on product to be sold. A bar code reader emits a beam of light, which reflects off the bar code image.
A light sensitive detector in the barcode reader identifies the bar code image by recognising special bars at both the ends of the image.
Once code is identified, it is converted into a numeric code. A perfect example of a barcode reader is its use in a super market where barcode scanner reads the price of a product.
Software like Wasp, Barcode Pro are used for scanning and printing barcodes.
A barcode is a machine readable representation of information in the form of stripes of dark and light ink.