CodeWithChitu
UNIT 3
HARDWARE – Input Device Notes
IGCSE - 0478/2210/9084
Objectives:
• Understand what is meant by an input device and why it is required
• Understand what is meant by a sensor and the purposes of sensors
• Identify the type of data captured by each sensor and understand when
each sensor would be used, including selecting the most suitable
sensor for a given context
https://www.youtube.com/@codewithchittu1095
,HARD WARE - INPUT DEVICE UNIT- III
Input Devices
• Every computer system receives commands and data, from the real world, via input
devices
• Input devices converts inputs into digital data which can be processed
• For conventional computer systems, such as desktop computers and laptops, the most
common input devices are the mouse and the keyboard
• There are a wide range of input devices used in more specialist computer systems such as
scanners and sensors
Keyboard
• A keyboard is the most common device used for text-based data input
• They are connected either by a USB cable or wirelessly to the computer system
• They are built into laptops.
• Smartphones and tablets have virtual keyboards
Working of Keyboard:
• Each character has an ASCII value and is converted into a digital signal
• Keyboard has its processor and circuitry that carries information to and from that processor.
• A large part of this circuitry makes up the key matrix. The key matrix is a grid of circuits
underneath the keys.
• If a key is pressed on a keyboard, it presses a switch, completing the circuit and allowing a
tiny amount of current to flow through.
• The key location will be sent to the memory present on the keyboard. By using the charter
map the pressed key will be recognized and sent to the CPU.
• CPU refers to the ASCII table to display the corresponding keypress of the Keyboard
COMPUTER SCIENCE /0478/ 1
, HARD WARE - INPUT DEVICE UNIT- III
Mouse
• A mouse use a laser to detect and track movement, this is then processed by a
microprocessor which interprets the movement and replicates it when moving a virtual
cursor on-screen
• Items can be selected or moved using the left mouse button, whilst the right button usually
displays additional menus
• They can be wired or wireless
• They are used to control the cursor in a Graphical User Interface (GUIs)
• They are simple to use and provide the user with an intuitive way to navigate the computer
• They are reliable due to no moving parts
.
Touch Screen:
A touch screen is both an input and output device. It shows you options to choose from
(output), and you make a selection by touching the screen with your finger (input).
Application : Frequently utilized in public settings such as:
• Cash machines, or ATMs
• Airport or theater ticket machines
• Museums and libraries
• helpful in locations where mice or keyboards could be lost or stolen.
• incredibly intuitive (easy to use and comprehend).
• becoming more affordable to produce.
• probably going to be the most popular way that we use electronics.
The three major types of touchscreen technologies in mobile phones are:
• Capacitive
• Infra-red
• Resistive
COMPUTER SCIENCE /0478/ 2
UNIT 3
HARDWARE – Input Device Notes
IGCSE - 0478/2210/9084
Objectives:
• Understand what is meant by an input device and why it is required
• Understand what is meant by a sensor and the purposes of sensors
• Identify the type of data captured by each sensor and understand when
each sensor would be used, including selecting the most suitable
sensor for a given context
https://www.youtube.com/@codewithchittu1095
,HARD WARE - INPUT DEVICE UNIT- III
Input Devices
• Every computer system receives commands and data, from the real world, via input
devices
• Input devices converts inputs into digital data which can be processed
• For conventional computer systems, such as desktop computers and laptops, the most
common input devices are the mouse and the keyboard
• There are a wide range of input devices used in more specialist computer systems such as
scanners and sensors
Keyboard
• A keyboard is the most common device used for text-based data input
• They are connected either by a USB cable or wirelessly to the computer system
• They are built into laptops.
• Smartphones and tablets have virtual keyboards
Working of Keyboard:
• Each character has an ASCII value and is converted into a digital signal
• Keyboard has its processor and circuitry that carries information to and from that processor.
• A large part of this circuitry makes up the key matrix. The key matrix is a grid of circuits
underneath the keys.
• If a key is pressed on a keyboard, it presses a switch, completing the circuit and allowing a
tiny amount of current to flow through.
• The key location will be sent to the memory present on the keyboard. By using the charter
map the pressed key will be recognized and sent to the CPU.
• CPU refers to the ASCII table to display the corresponding keypress of the Keyboard
COMPUTER SCIENCE /0478/ 1
, HARD WARE - INPUT DEVICE UNIT- III
Mouse
• A mouse use a laser to detect and track movement, this is then processed by a
microprocessor which interprets the movement and replicates it when moving a virtual
cursor on-screen
• Items can be selected or moved using the left mouse button, whilst the right button usually
displays additional menus
• They can be wired or wireless
• They are used to control the cursor in a Graphical User Interface (GUIs)
• They are simple to use and provide the user with an intuitive way to navigate the computer
• They are reliable due to no moving parts
.
Touch Screen:
A touch screen is both an input and output device. It shows you options to choose from
(output), and you make a selection by touching the screen with your finger (input).
Application : Frequently utilized in public settings such as:
• Cash machines, or ATMs
• Airport or theater ticket machines
• Museums and libraries
• helpful in locations where mice or keyboards could be lost or stolen.
• incredibly intuitive (easy to use and comprehend).
• becoming more affordable to produce.
• probably going to be the most popular way that we use electronics.
The three major types of touchscreen technologies in mobile phones are:
• Capacitive
• Infra-red
• Resistive
COMPUTER SCIENCE /0478/ 2
