Lesson Notes By Weeks and Term v3 - Senior Secondary 1
Input Devices
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Input Devices
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Subject: Computer & IT
Class: Senior Secondary 1
Term: 2nd Term
Week: 2
Theme: Computer Hardware
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Define in putdevice List in put devices State the featuresand uses of keyboard Operate the keyboard State the featuresand uses of mouse State how the mouse works Operate the mouse
to mouse, often used in professional settings).
Graphics Tablet: A flat surface used with a stylus to draw or handwrite directly into the computer, popular with graphic designers and artists.
Biometric Devices: Devices that capture unique biological characteristics for identification and authentication.
Fingerprint Scanner: Scans and verifies fingerprints. (e.g., for NIN registration, accessing banking apps, attendance systems in government offices).
Iris Scanner: Scans the unique patterns in an individual's iris.
Card Readers: Devices used to read data from various types of cards.
Smart Card Reader: Reads data from smart cards (cards with an embedded microchip). (e.g., SIM card registration, e-banking tokens, National ID cards).
Magnetic Stripe Reader: Reads data from magnetic stripes on cards. (e.g., older debit/credit cards).
Memory Card Reader: Reads data from memory cards (e.g., SD cards, MicroSD cards) used in cameras, phones, etc. (e.g., transferring photos from a digital camera to a computer). 2.1 Definition of an Input Device An input device is any peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system, such as a computer or information appliance. It acts as an interface between the user and the computer, translating human-readable information (text, clicks, images, sound) into a format that the computer can understand and process (binary code). Without input devices, users cannot interact with a computer system or supply it with the necessary information to perform tasks. 2.2 Classification of Input Devices Input devices can be broadly classified based on the type of data they input: Text and Number Entry Devices: Keyboard Pointing Devices: Mouse, Trackball, Joystick, Light Pen, Touchpad, Touchscreen Scanning Devices: Scanner, Barcode Reader, Optical Mark Reader (OMR), Optical Character Reader (OCR)
Audio/Video Input Devices: Microphone, Webcam Biometric Input Devices: Fingerprint Scanner, Iris Scanner Card Readers: Smart Card Reader, Magnetic Stripe Reader, Memory Card Reader 2.3 Detailed Explanation of Common Input Devices 2.3.1 Keyboard The keyboard is the most common and fundamental text-based input device. It is primarily used for entering text, numbers, and commands into the computer.
Features: QWERTY Layout: The most common keyboard layout, named after the first six letters on the top-left row of alphabetic keys.
Alphanumeric Keys: Keys for letters (A-Z) and numbers (0-9).
Numeric Keypad: A section of the keyboard (usually on the right) dedicated to numbers, arranged like a calculator, for fast numerical entry.
Function Keys (F1-F12): Keys with predefined functions that vary depending on the program being used (e.g., F1 for help).
Control Keys: Keys like `Ctrl` (Control), `Alt` (Alternate), `Shift`, `Enter` (Return), `Backspace`, `Delete`, `Tab`, `Caps Lock`, `Esc` (Escape). These keys often modify the function of other keys or perform specific actions.
Navigation/Arrow Keys: Four keys (Up, Down, Left, Right) used to move the cursor or scroll through documents.
Special Purpose Keys: Keys like `Print Screen`, `Scroll Lock`, `Pause/Break`, `Home`, `End`, `Page Up`, `Page Down`.
Uses: Typing documents, emails, messages, and web addresses. Entering data into spreadsheets and databases. Issuing commands to the operating system or software applications (e.g., `Ctrl+S` to save, `Alt+F4` to close a window). Navigating through menus and web pages.
How it Works: When a key is pressed, a small electrical circuit beneath that key is completed. This sends a unique signal (scan code) to the keyboard controller chip within the keyboard. The controller then converts this signal into a character code (e.g., ASCII code) and sends it to the computer's CPU via a cable or wireless connection. The CPU interprets this code and displays the corresponding character on the screen or performs the associated command.
Operation:
1. Typing Text: Place fingers on the home row (ASDF JKL;). Press individual keys to produce characters. Use `Shift` for uppercase letters and symbols.
2. Using Spacebar: Press the long bar at the bottom to insert a space between words.
3. Correcting Errors: Use `Backspace` to delete characters to the left of the cursor, and `Delete` to remove characters to the right.
4. New Line/Paragraph: Press `Enter` to move the cursor to the beginning of the next line or to execute a command.
5. Navigation: Use `Arrow keys` to move the cursor without deleting text. Use `Page Up` and `Page Down` to scroll through documents. 2.3.2 Mouse A mouse is a pointing device used to control the movement of a cursor or pointer on a computer screen.
Features: Left Button: Primarily used for selecting items, clicking links, opening files, and dragging objects.
Right Button: Opens context-sensitive menus (shortcut menus) that offer options relevant to the item pointed at.
Scroll Wheel (or Middle Button): Used for scrolling through documents or web pages vertically. It can sometimes also be pressed as a third button.
Ergonomic Design: Modern mice are often designed to fit comfortably in the user's hand.
Types of Mouse: Mechanical Mouse: Uses a rubber ball underneath to detect movement. (Less common now) * Optical Mouse: Uses an LED light and a sensor to detect movement. files, and dragging objects.
Right Button: Opens context-sensitive menus (shortcut menus) that offer options relevant to the item pointed at.
Scroll Wheel (or Middle Button): Used for scrolling through documents or web pages vertically. It can sometimes also be pressed as a third button.
Ergonomic Design: Modern mice are often designed to fit comfortably in the user's hand.
Types of Mouse: Mechanical Mouse: Uses a rubber ball underneath to detect movement. (Less common now)
Optical Mouse: Uses an LED light and a sensor to detect movement. It tracks movement by capturing successive images of the surface beneath it.
Laser Mouse: A more precise type of optical mouse that uses an infrared laser diode.
Wireless Mouse: Connects to the computer via Bluetooth or a USB receiver, eliminating the need for a cable.
Uses: Pointing: Moving the cursor to a specific location on the screen.
Clicking: Pressing the left button once to select an item or activate a link.
Double-clicking: Pressing the left button twice quickly to open a program or file.
Right-clicking: Pressing the right button once to open a context menu.
Dragging and Dropping: Clicking and holding the left button on an item, moving the mouse to a new location, and then releasing the button to move the item.
Scrolling: Using the scroll wheel to move through content.
How it Works: Optical Mouse: An optical mouse emits a light (usually red LED) onto the surface below it. A small camera sensor continuously takes thousands of "pictures" (images) of the surface pattern per second. A Digital Signal Processor (DSP) inside the mouse analyzes these images, detecting changes in the pattern as the mouse moves. It then translates these changes into coordinates (X and Y axis movements) which are sent to the computer, causing the cursor on the screen to move accordingly.
Operation:
1. Holding the Mouse: Position the hand comfortably over the mouse, with the index finger on the left button and the middle finger on the right button.
2. Moving the Cursor: Gently slide the mouse across a flat surface (mouse pad recommended). The cursor on the screen will mimic the mouse's movement.
3. Clicking: Press the left button down and release it quickly.
4. Double-Clicking: Press the left button twice in rapid succession.
5. Right-Clicking: Press the right button down and release it quickly.
6. Dragging: Point to an item, press and hold the left button, move the mouse to the desired new location, then release the button.
7. Scrolling: Rotate the scroll wheel forward or backward to move through content. 2.3.3 Other Input Devices (Brief Overview)
Scanner: Converts physical documents or images into digital format. (e.g., scanning JAMB registration documents, converting physical photos to digital copies).
Microphone: Captures sound (voice, music) and converts it into digital audio signals. (e.g., voice notes on WhatsApp, recording podcasts, online meetings).
Webcam: Captures still images and live video, enabling video conferencing and surveillance. (e.g., online classes, video calls with family abroad).
Touchscreen: A display screen that responds to touch input directly on its surface. (e.g., smartphones, tablets, ATMs, POS terminals for payment in Nigerian supermarkets).
Joystick: A control stick used primarily for playing computer games, providing multi-directional movement input. (e.g., in cybercafés for gaming).
Light Pen: A light-sensitive pointing device used for drawing or selecting items on a CRT display. (Less common now).
Trackball: A stationary pointing device with a ball on top that is rotated by the user's thumb or fingers to move the cursor. (Alternative to mouse, often used in professional settings).
Graphics Tablet: A flat surface used with a stylus to draw or handwrite directly into the computer, popular with graphic designers and artists.
Biometric Devices: Devices that capture unique biological characteristics for identification and authentication.
Fingerprint Scanner: Scans and verifies fingerprints. (e.g., for NIN registration, accessing banking apps, attendance systems in government offices).
Iris Scanner: Scans the unique patterns in an individual's iris.
Card Readers: Devices used to read data from various types of cards. * Smart Card Reader: Reads Teacher Activities: Introduction (10 minutes): Begin by asking students how they give instructions or put information into a computer or a phone. (e.g., "How do you type a message on your phone?", "How do you select an option at an ATM?"). Lead a brief brainstorming session to identify devices they use for these actions. Introduce the term "input device" and explain its fundamental role.
Concept Explanation (20 minutes): Define input device clearly. Present various input devices (if available, show physical examples of a keyboard, mouse, perhaps a scanner or microphone).
Focus intensely on the keyboard: Project or draw a diagram of a keyboard. Point out and explain the different sections (alphanumeric, numeric keypad, function keys, control keys, navigation keys). Explain their uses and how key presses translate to computer input.
Focus intensely on the mouse: Project or draw a diagram of a mouse, highlighting buttons and scroll wheel. Explain its functions (pointing, clicking, double-clicking, right-clicking, dragging, scrolling). Briefly explain how an optical mouse works (light, sensor, movement detection). Briefly introduce other common input devices (scanner, microphone, webcam, touchscreen, card reader, biometric devices) by explaining their function and giving a relevant Nigerian example for each.
Demonstration (15 minutes): If computers are available, the teacher demonstrates basic keyboard operations (typing, using Shift, Backspace, Enter, arrow keys) and mouse operations (moving cursor, clicking, double-clicking, right-clicking, dragging, scrolling) using a word processor or a web browser. If no computers, the teacher can use a physical keyboard and mouse to simulate actions, describing each step verbally and visually. Students can mimic finger placement.
Guided Practice Facilitation (15 minutes): Guide students through practical exercises (if computers are available). Provide worksheets with scenarios for keyboard/mouse actions (e.g., "Type your name and state of origin," "Open a file named 'MyDocument'"). Monitor students, provide immediate feedback, and correct posture/technique. For classrooms without computers, facilitate a "virtual practice" where students describe the steps they would take to perform specific keyboard/mouse actions, or draw diagrams of the devices and label their functions.
Activity & Discussion (15 minutes): Divide students into small groups. Assign each group a few input devices (e.g., Group A: Keyboard, Mouse; Group B: Scanner, Microphone; Group C: Touchscreen, Card Reader). Each group discusses the features and uses of their assigned devices, and prepares to present their findings.
Wrap-up and Recap (5 minutes): Summarize key concepts covered. Address any remaining questions.
Student Activities: Participate in brainstorming and Q&A sessions. Listen attentively and take notes during concept explanations. Observe teacher demonstrations carefully, mentally noting the steps. Practical Application (if computers available): Practice typing short sentences, using Shift, Backspace, and Enter keys. Practice moving the mouse pointer, clicking, double-clicking, right-clicking, and dragging simple objects (e.g., desktop icons). Practice scrolling through a document or webpage.
Interactive Learning (if no computers): Draw and label a keyboard and mouse, indicating key/button functions. Verbally describe the steps to perform specific keyboard and mouse operations. Engage in group discussions, contributing ideas on features and uses of various input devices, and presenting their findings. Answer questions posed by the teacher.
JAMB Computer-Based Test (CBT): Students' ability to effectively use a keyboard for entering personal details and examination numbers, and a mouse for selecting answers, navigating questions, and clicking "Next" or "Submit," is paramount for success in these national examinations. Lack of familiarity with these input devices often contributes to poor performance, even for academically brilliant students.
Banking and Financial Transactions: Input devices like touchscreens (on ATMs and POS terminals in shops/supermarkets), keypads (on ATMs for PIN entry), and smart card readers (for debit/credit cards or SIM card registration with NIN) are integral to daily financial activities in Nigeria. Understanding their function and safe operation is crucial for personal finance management and preventing fraud.
Government Services and Registration: Many government initiatives, such as the National Identity Number (NIN) registration, voter registration, and driver's license applications, utilize biometric input devices (like fingerprint scanners) for identification. Keyboard and mouse skills are also required for data entry during these processes. This highlights the importance of input devices for civic engagement and accessing essential services.