1.3 Input/Output (I/O) Devices

• Types of input devices and how they work
• Keying, pointing, scanning, voice and touch input
• Barcodes and QR codes
• Types of output devices and how they work
• Printers, monitors, projectors, plotters, speakers and actuators
• Criteria for selecting input and output devices
• Technological advancement in input and output devices

• describe types of input and output devices used in computer systems
• examine the criteria used in selecting input and output devices
• use input and output devices to perform tasks
• appreciate the advancement of input and output devices used in computer systems

“How do input and output devices operate?”

“What are the technological advancements in input and output devices?”

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1. Input devices and how they work
   40 min · 1 practice tasks · quiz
   The six groups of input device, how each turns something physical into binary, and the difference between keyed and direct data entry.
2. Output devices, and how to choose input and output equipment
   40 min · 1 practice tasks · quiz
   Monitors, printers, plotters, projectors, speakers and actuators, how each works, and the criteria that should decide a purchase.
3. The keyboard: scan codes, layouts and keypads
   40 min · 1 practice tasks · quiz
   How a keypress becomes a character, why QWERTY is a layout not a law, and how till and on-screen keyboards still use the same idea.
4. Pointing devices: mice, pads and digitisers
   40 min · 1 practice tasks · quiz
   How an optical mouse measures movement, how a touchpad and a graphics tablet differ, and when each is the right tool.
5. Scanners, OMR, OCR and MICR
   40 min · 1 practice tasks · quiz
   How a flatbed scanner builds an image, how a 3D scanner captures shape, and the four specialised readers used in exams, documents, cheques and shops.
6. RFID, biometrics and card readers
   40 min · 1 practice tasks · quiz
   Radio tags that need no line of sight, fingerprint and face summaries, and magnetic-stripe against chip cards - including Kenyan livestock, libraries and ATMs.
7. Touch screens: resistive, capacitive and infrared
   40 min · 1 practice tasks · quiz
   Three ways a panel can both show a picture and take a touch, and how to tell which technology is in a phone, an ATM or a classroom board.
8. Barcodes, QR codes and paying by scan
   40 min · 1 practice tasks · quiz
   One-dimensional barcodes against two-dimensional QR codes, what a till actually looks up, and the three habits that stop sticker fraud on Kenyan payment signs.
9. Voice, cameras and sensors
   40 min · 1 practice tasks · quiz
   How a microphone and a camera turn waves and light into numbers, and how sensors let a computer read a Kenyan greenhouse, poultry house or weather station.
10. Monitors: LCD, OLED and the numbers on the box
    40 min · 1 practice tasks · quiz
    How an LCD makes colour, why an LED monitor is still an LCD, what OLED adds and costs, and how to read size, resolution, refresh rate and aspect ratio.
11. Printers, plotters and cost per page
    40 min · 1 practice tasks · quiz
    Impact against non-impact, a worked cost-per-page comparison in Kenyan shillings, and when a plotter or a 3D printer is the right output device.
12. Choosing devices, visiting a workplace, and e-waste
    40 min · 1 practice tasks · quiz
    A selection checklist applied to Kenyan scenarios, a structured visit to a computer user environment, and why a purchase is also a disposal decision.