1 Pertemuan 11 Hardware: Input Devices Matakuliah: T0604-Pengantar Teknologi Informasi Tahun: 2008 Versi: 2.0/0.0 Williams, B.K, Stacy C. Sawyer (2007). Using Information Technology: A Practical Introduction to Computers & Communications. Seventh Edition, McGraw-Hill, New York. ISBN-13: Sumber: Chapter 5. Hardware: Input & Output, p.251

2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : menjelaskan jenis-jenis dan kegunaan serta cara kerja peralatan input (C2)

3 Outline Materi Input & Output Input Hardware

5-4 Input & Output Input Hardware –Devices that translate data into a form the computer can process –Translates words, numbers, sounds, and pictures into binary Output Hardware –Devices that translate information processed by the computer into a form humans can understand –Translates binary into words, numbers, sounds, and pictures

5-5 Input Hardware Keyboards: convert letters, numbers, and characters into electrical signals –English keyboards differ from foreign language keyboards –Follow this link to see what a Russian Cyrillic keyboard layout looks like –Even languages that are close to ours like German have different keyboard layouts, such as can be seen on Microsoft’s web site –Even touch typists must watch their fingers when they travel to Internet Cafes in foreign countries!

5-6 Input Hardware How keyboards work: –You press a key –This interrupts the current flowing through the circuits –Processor determines where the break occurs –It compares the location of the break with the (x,y) character map for the language on the keyboard’s ROM chip –A character is stored in 16-byte keyboard memory buffer –Then sent to PC as a data stream via wire or wireless connection –OS interprets its own operating-system-specific commands and sends the others to the application for interpretation

5-7 Input Hardware Keyboard types 104 – 108 keys desktop standard 85 keys for laptops –Wired Connect to CPU via a serial or USB port –Wireless use either IR (infrared) technology Radio Frequency (RF) technology Require line of sight to connect Virtual keyboard used with PDAs and smartphones

5-8 Input Hardware Terminal Types Dumb Terminals –a.k.a. Video Display Terminal (VDT) –Has display screen and keyboard –Can do input and output only – no data processing Intelligent Terminals –Has screen, keyboard, and memory –Can perform some local functions Internet Terminals –Powers directly up into a browser Web terminal displays web pages on a TV set Network computer is a stripped-down PC to connect people to networks Online game player connects to internet for online gaming PC/TV merges a full-blown PC with a TV PDA is a handheld computer with a tiny keyboard

5-9 Input Hardware PDA Keyboards –Problem: Make them too small and they are unusable –Problem: Make them too big and the PDA is too big –Solutions: Some PDAs use a stylus Some PDAs use a foldable keyboard Some PDAs use a 20-key mini-keyboard

5-10 Input Hardware Pointing Devices Control the position of the cursor or pointer in the screen and allow the user to select options displayed on the screen Mouse is the principal pointing tool –Rolls around on a mouse pad or desktop and directs a pointer on the computer’s display screen Ball inside the mouse touches the desktop and rolls around Two internal rollers touch the ball One roller picks up motion in x (up), the other in y (down) The rollers turn a shaft that spins a disk that breaks an LED signal into light pulses that are seen by an infrared sensor Processor chip in mouse reads the pulses and turns it into binary Discussion Question: What is the difference between “cursor” and “curser”?

5-11 Input Hardware Pointing Devices Trackball –A movable ball mounted on top of a stationary device –Good for locations where a mouse couldn’t move enough –Requires more frequent cleaning to remove finger oils Touchpad –To use: slide your finger over this small flat surface –Click by tapping you finger on the surface –May require more practice to use than a mouse Pointing Stick –Looks like a pencil eraser in the lower center of a laptop keyboard

5-12 Input Hardware Pointing Devices Touch Screens –A video display screen sensitized to receive input from a finger –Cruder than a mouse, because fingers are big –Problems: touch screens that show a display that is not precisely aligned with the input Pen input –Use a pen-like stylus for input rather than typing on a keyboard –Use handwriting recognition to translate cursive writing into data

5-13 Input Hardware Light Pen –A light-sensitive pen-like device that uses a wired connection to a computer terminal –Bring the pen to the desired point on the display screen and press a button to identify the screen location –Used in situations that require gloves –Less crude than a touch screen Digitizer –Uses an electronic pen or puck to convert drawings and photos to digital data –Digitizing tablets are used in architecture

5-14 Input Hardware Scanning & Reading Devices Source Data Entry devices create machine- readable data and feed it directly into the computer –Scanners Use light-sensing equipment to translate images of text, drawings, and photos into digital form Image scanners are used in electronic imaging Resolution refers to the image sharpness, measured in dots per inch (dpi) Flatbed scanners work like photocopiers – the image is placed on the glass surface, then scanned Other types are sheet-fed, hand-held, drum, and pen scanners

5-15 Input Hardware Bar-Code Readers Photoelectric (optical) scanners that translate bar code symbols into digital code The digital code is then sent to a computer The computer looks up the item and displays its name and pricing info –Bar code types 1D holds up to 16 ASCII characters 2D can hold 1,000 to 2,000 ASCII characters 3D is “bumpy” code that differentiates by symbol height –Can be used on metal, hard rubber, other tough surfaces

5-16 Input Hardware Mark Recognition Readers Bar code readers –MICR – Magnetic-ink character recognition Uses special magnetized inks Must be read by a special scanner that reads this ink –OMR – Optical mark recognition Uses a special scanner that reads bubble marks Used in standardized tests like the ACT and SAT –OCR – Optical character recognition Converts scanned text from images (pictures of the text) to an editable text format You use this to read in non-computer documents where you don’t have the source files

5-17 Input Hardware Fax Machines Facsimile Transmission Machines – scan an image and send it as electronic signals over telephone lines to a receiving fax, which prints out the image on paper –Dedicated fax machine Is a stand-alone unit that only sends and receives faxed documents –Fax modem Is a circuit board installed in the PC Is a modem that can send and receive faxes –Can send documents directly from your word processor to a fax machine –Saves you printing out the document, then faxing it

5-18 Input Hardware Audio Input Devices Records analog sound and translates it into digital files for storage and processing Two ways to digitize audio –Sound Board An add-on board in a PC that converts analog sound to digital sound, stores it, and plays it back to speakers or amp –MIDI Board Stands for Musical Instrument Digital Exchange Uses a standard for the interchange between musical instruments, synthesizers, and PCs

5-19 Input Hardware Webcams and Video-input Cards Webcams –Video cameras attached to a computer to record live moving images then post them to a website in real time –Require special software, usually included with the camera Frame-grabber video card –Can capture and digitize 1 frame at a time Full-motion video card –Can convert analog to digital signals at rates up to 30 frames per second –Looks like a motion picture Discussion Question: Why might it be unwise to install a webcam on your PC?

5-20 Input Hardware Digital Cameras Use a light-sensitive processor chip to capture photographic images in digital form and store them on a small diskette in the camera or on flash memory cards –Most can be connected to a PC by USB or FireWire –Can allow you to take more pictures and decide which ones to print and save –But pictures are subject to loss by diskette or flash memory failure or computer virus if you store them on the PC

5-21 Input Hardware Camera Phones Digital cameras are now on cellphones –Convenience of being able to take photos, then instantly or message them to someone else –Can provide instant record of traffic accidents, etc Discussion Question: Why do you suppose cellphones are now banned on secure U.S. military bases? Where else besides military bases might they pose a security problem?

5-22 Input Hardware Speech-Recognition Systems Uses a microphone or telephone as an input device. Converts a person’s speech into digital signals by comparing against 200,000 or so stored patterns. –Used in places where people need their hands free – warehouses, car radios, stock exchange trades –Helpful for people with visual or physical disabilities that prevent them from using other input devices –Still not easy enough to use to substitute for the mouse/keyboard for fast document processing ScanSoft’s Open Speech Dialog Apple Speech Recognition ScanSoft’s Navigon MobileNavigator 5

5-23 Input Hardware RFID Tags Radio-frequency ID tags are based on an identifying tag with a microchip containing specific code numbers –Scanners use radio waves to read them and match the codes to a database –Enables items to be tracked without physical contact Drivers put RFID tags in cars to automatically pay tolls FDA is tagging certain drugs with RFID to avoid counterfeits Carmakers are using it for car electronic keyless entry RFID tags are implanted under skin of pets to aid in recovery and identification when they get lost

5-24 Input Hardware Biometrics The science of measuring individual body characteristics, then using them to identify a person through a fingerprint, hand, eye, or facial characteristic –Becoming a big business as more companies become concerned about security –Makes identity theft much more difficult when records are identified by biometrics as well as passwords –For more information see

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