joy sticks & touch screens

8/4/2019 Joy Sticks & Touch Screens

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Group 6 Presentation

Fundamentals of Computer Hardware

Joy Sticks & Touch Screens


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Joy Sticks


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JOYSTICKS A joystick is an input device that consists of a stick that pivots on abase and reports its angle or direction to the device it is controlling

however, recent technologies have developed some joystick to be asimple device that has buttons only mounted on a base.

The movement of the base determines the direction f the pointer.Joystick controls symbols and pointers in the same way a mousedoes.

They differ only in the sense that a mouse pointer stops moving themoment you move the mouse while for some joysticks you have toput the stick in an upright position.

A joystick also known as control columns are the principal controlmechanism in a tight area of many civilian and military aircraft.They consist of supplementary switches on them to control otheraspects on the aircraft.

Joysticks are also often used to control video games and have one ormore push buttons whose state can be read by the computer.

The most popular variation of a joystick used on modern video gameis the analog stick, plays station.

Joysticks are also used for controlling machines such as cranes,trucks, underwater machines.


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Advantages of Using JoySticks

1. its easy to play with

2. it can move in any direction


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Disadvantages of Using JoySticksHand injuiresControl Problems

Not compatible with most computers


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TYPES OF JOYSTICKS

Digital Joysticks - it is most common inPCs and employs simple movements of left,right, up, down and firing commands.

Paddle Joystick consists of one knobused to control the game on one firingbutton. It is one of the oldest joystickmechanism developed.

Analog- it combines both conceptspresented in the digital and paddle joystick,they control the game like a digital joystick


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Touch Screens


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TOUCH SCREEN

Touch screens replace the standard computermouse by allowing direct interaction with thescreen with a finger, pen or other pointingdevice. These products can be used byindividuals who have difficulty manipulating

computer mice.A touch-screen is an intuitive computer inputdevice that works by simply touching thedisplay screen, either by a finger, or with astylus, rather than typing on a keyboard orpointing with a mouse. Computers with touch-screens have a smaller footprint, and can bemounted in smaller spaces; they have fewermovable parts, and can be sealed. Touch-screens may be built in, or added on. Add-ontouch-screens are external frames with a clear

see-through touch-screen which mount onto themonitor bezel and have a controller built into

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comprises the following three basiccomponents;

a touch-screen sensor panel, that sits abovethe display and which generates appropriatevoltages according to where, precisely, it istouched

a touch-screen controller, that processes thesignals received from the sensor and

translates these into touch event data whichis passed to the PC's processor, usually via aserial or USB interface

a software driver, provides an interface to the

PC's operating system and which translatesthe touch event data into mouse events


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Types of Touch ScreensResistiveInfrared

Surface Acoustic Wave

Capacitive


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ResistiveResistive touch-screens respond to the pressure

of a finger, a fingernail, or a stylus. Theytypically comprise a glass or acrylic base that iscoated with electrically conductive and resistive

layers. The thin layers are separated by invisibleseparator dots. When operating, an electricalcurrent is constantly flowing through theconductive material. In the absence of a touch,the separator dots prevent the conductive layerfrom making contact with the resistive layer.When pressure is applied to the screen thelayers are pressed together, causing a changein the electrical current. This is detected by the

touch-screen controller, which interprets it as a-


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InfraredInfrared touch-screens are based on light-beam

interruption technology. Instead of placing alayer on the display surface, a frame surroundsit. The frame assembly is comprised of printedwiring boards on which the opto-electronics are

mounted and is concealed behind an IR-transparent bezel. The bezel shields the opto-electronics from the operating environmentwhile allowing the IR beams to pass through.

The frame contains light sources - or light-emitting diodes - on one side, and light

detectors - or photosensors - on the oppositeside. The effect of this is to create an opticalgrid across the screen. When any object touchesthe screen, the invisible light beam isinterrupted, causing a drop in the signal

received by the photosensors. Based on whichphotosensors stop receiving the light signals, it


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Surface Acoustic WaveSurface Acoustic Wave technology is one of

the most advanced touch-screen types.SAW touch-screens work much like theirinfrared brethren except that sound waves,

not light beams, are cast across the screenby transducers. Two sound waves, oneemanating from the left of the screen andanother from the top, move across the

screen's surface. The waves continuallybounce off reflectors located on all sides ofthe screen until they reach sensors locatedon the opposite side from where they

originated.


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Surface Acoustic WaveContdWhen a finger touches the screen, the waves

are absorbed and their rate of travel thusslowed. Since the receivers know how quicklythe waves should arrive relative to when theywere sent, the resulting delay allows them to

determine the x- and y-coordinates of the pointof contact and the appropriate touch event tobe registered, Unlike other touch-screentechnologies, the z-axis (depth) of the touchevent can also be calculated; if the screen istouched with more than usual force, the water

in the finger absorbs more of the wave's energy,thereby delaying it more.

Because the panel is all glass and there are nolayers that can be worn, Surface Acoustic Wavetouch-screens are highly durable and exhibit

excellent clarity characteristics. The technologyis recommended for public information kiosks,


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CapacitiveCapacitive touch-screens consist of a glass

panel with a capacitive (charge storing) materialcoating its surface. Unlike resistive touch-screens, where any object can create a touch,they require contact with a bare finger or

conductive stylus. When the screen is touchedby an appropriate conductive object, currentfrom each corner of the touch-screen is drawnto the point of contact. This causes oscillatorcircuits located at corners of the screen to varyin frequency depending on where the screen

was touched. The resultant frequency changesare measured to determine the x- and y- co-ordinates of the touch event.

Capacitive type touch-screens are very durable,and have a high clarity. They are used in a wide

range of applications, from restaurant and POSuse to industrial controls and information kiosks.


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The table below summarises the principaladvantages/disadvantages of each of the

described technologies:

Resistive Infrared Surface Acoustic Wave Capacitive

Touch resolution High High Average High

Clarity Average Good Good Good

Operation Finger or stylus Finger or stylus Finger or soft-tipped

stylus

Finger only

Durability Can be damaged by

sharp objects

Highly durable Susceptible to dirt and

moisture

Highly durable

joy sticks & touch screens

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