3.2.8+Input+&+Output+Devices

=__Input / Output Devices__=

**__Keyboards__**
 * Input device, allows typing of characters in certain word processing programs[[image:Keyboard.jpg width="391" height="137" align="right" caption="A standard German keyboard"]]
 * Keyboards contain a total of 101-130 keys
 * Keyboards can have function keys that do certain things
 * Short cuts can be used for specific, set tasks (ex. [Ctrl]+[Alt]+[Del] in the Windows operating system can open the task manager)
 * **A****dvantages**
 * Keyboard allow for easy word processing
 * Not dependent on a GUI OS
 * Using short cuts can be faster than using the mouse
 * **D****isadvantages**
 * When using a keyboard too much, it can cause carpal tunnel syndrome
 * It is difficult to ex. draw things in graphics programs with a keyboard


 * __Mouse__ **
 * A Mouse is a computing input device that allows for control over the cursor, usally standard with 3 buttons (2 for selecting and a wheel for [[image:Mouse.jpg width="266" height="149" align="right" caption="A standard 3-button mouse"]]scrolling can be used to open, close, and minimize windows on the monitor as well as moving objects around on the screen.
 * **Advantages**
 * Allows not fully defined inputs (ex. drawing images in graphics programs)
 * **Disadvantages**
 * Takes up much space if your working in a small area and requires cleaning to function properly
 * Can only be used with a GUI (Graphic User Interface)

**__Touch screen__**
 * A touch screen is a screen which can be directly touched in order to interact with the computer[[image:touchscreen.jpg width="207" height="290" align="right" caption="An example of a touch screen in a e-reader"]]
 * Touch screens are used most often with hand held devices making the screen larger because there is no need for extra buttons
 * **Advantages**
 * The fact that everything can be done on a touch screen without the help of other input devices (keyboards or mice)
 * **D****isadvantages**
 * It can be hard to select small items on a touch screen
 * Touch screens have to calibrated every once in a while

**__Optical Character Recognition (OCR)__**
 * An OCR is a device that scans text (handwritten, printed or written on a typewriter) via a scanner or a digital image and converts that data into text that can be edited via computer.
 * ** Advantages **
 * No need to re-type a text, which is only available as hard-copy
 * **Disadvantages**
 * Errors in the character-recognition may occur
 * OCRs are not very efficient recognizing handwriting or fonts that are similar to handwriting

__**Magnetic Ink Character Recognition (MICR)**__

 * Uses specific ink that contains iron-oxide that can be read by magnetic scanners
 * **Advantages**
 * Can Be read very easily
 * Very low error rate
 * **Disadvantages**
 * Only allows numbers

**__Speakers__**
 * Outputs sound.[[image:Speaker.jpg width="92" height="235" align="right" caption="A speaker"]]
 * **Advantages**
 * Surround sound can be used for realistic sound experience
 * **Disadvantages**
 * Might disturb other people

**__Headphones__**

 * Outputs sound close up to the user's ear
 * **Advantages**
 * Does not disturb anyone else
 * **Disadvantages**
 * It is limited to stereo

**__Microphones__**

 * Input sound by the user
 * ====**Advantages**====
 * very easy to input sound
 * ====**Disadvantages**====
 * Speech recognition is not so developed and might have errors

** __Graphic Tablets__ **
 * Graphic Tables are a form of Input device that can be used to carefully draw or sketch images.
 * Graphic tablets use pens instead of mice is used to sketch anything onto the Graphic Tablet which then projects the lines on the screen.
 * **Advantages**
 * In a graphics program graphic tablets are more efficient
 * Graphic tablets offer accuracy which one might not have with a mouse otherwise.
 * **Disadvantages**
 * They are comparably expensive


 * __Printers__ **
 * A __Printer__ is a Output device which can print the digital data prepared on the computer onto paper or plastic foil.[[image:Printer.jpg width="159" height="195" align="right" caption="A laser printer"]]
 * **Advantages**
 * Easy to use and clean output of electronic data onto paper.
 * **Disadvantages**
 * Ink / toner is very expensive


 * __Plotters__ **
 * A plotter is a output device which can be used for special technical drawings and or vector graphics.
 * Other then the printer there is a actual pen going over the paper and sketching with machine like perfection of the data onto the paper.
 * **Advantages**
 * High precision and accuracy, also in terms of exact relationships in size and shapes which is very important with technical drawings
 * Are capable to draw on papers larger than A2
 * **Disadvantages**
 * Slower than normal Printers
 * More expensive and complex


 * __Monitors__ ** [[image:Monitor.jpg width="270" height="230" align="right" caption="A TFT-monitor"]]
 * A monitor is the main output device of a computer.
 * Is a visual output device
 * **Advantages**
 * Graphical representation of information and easy to handle using a mouse and keyboard.
 * **Disadvantages**
 * Relatively expensive compared to other out-/input devices


 * __Robotics__ **
 * Robots can be both an input an an output form of information to the computer.
 * Depending on what they are designed for they either take information from the computer to do something, or they can gather information using sensors and cameras to feed to the computer.
 * **Advantages**
 * Depending on what they are built to do they often do the job better then a human could
 * **Disadvantages**
 * If there is a programming error in the robot the robot may do something wrong, also a robot can not improvise.
 * So if there is a problem the robot will send an error while a human might just walk around it.


 * __Video Cameras__ **
 * Video cameras take over 24 pictures a second in order to play the outcome as a video. The footage is usually saved on either SD cards, SSDs, digital data tapes, or DVDs.
 * **Advantages**
 * It is possible to easily record a continuous motion with sound and play it back later on
 * **Disadvantages**
 * Movie files take up a large amount of space. The better the quality, the more space is used, in general.
 * It is difficult to handle a good video camera in order to produce very good quality video[[image:Scanner.jpg width="151" height="290" align="right" caption="A opened Scanner from above"]]


 * __Scanners__ **
 * Scanners make a high-resolution images of hard-copy objects
 * **Advantages**
 * Can scan images over 1200dpi and in general high quality images
 * **Disadvantages**
 * Scanning process can take a while, depending on the scanner
 * Only 2-Dimensional images can be scanned with the common 2D scanner


 * __LCD Panels__ **
 * A low-cost and little energy consuming way of showing data in a graphical manner used in TVs, monitors, calculators, etc.
 * **Advantages**
 * Low cost
 * Light weight
 * **Disadvantages:**
 * Limited viewing angles
 * Not suitable for dimly lit applications
 * High chances of dead pixels


 * __Speech Recognition__ **
 * Speech recognition is a form of audio input where the computer transforms the audio signals into commands or text
 * **Advantages**
 * Fast input of data
 * Enables data input for disabled people
 * **Disadvantages**
 * Nowadays the error rate is still high, compared with a keyboard or a mouse
 * Requires a lot of training to work properly


 * __Digital cameras__ **
 * Records images at different shutter speeds, light sensitivities and can zoom into varous depths.[[image:Camera.jpg width="272" height="174" align="right" caption="A Sony digital camera"]]
 * **Advantages**
 * Gives a fast high-quality image of something
 * Often has many adjustable settings that allow use in many situations
 * **Disadvantages**
 * Often times in modern digital cameras the view finder is removed

Edited by Daniel Gillo and Johann Beleites