Basic 8 · Computing · Input and Output Devices.
Direct Data Entry Devices and Output Devices
In this topic you will demonstrate understanding of direct data entry devices such as barcode, QR code, OCR, OMR and biometric readers, and examine the types and uses of modern output devices.
By the end of these notes you should be able to:
- Explain direct data entry and its advantages
- Describe common direct data entry devices and their uses
- Examine the types and uses of output devices
What you already know
- Input and output devices (Basic 7)
Copy everything that has a blue line on its left into your notebook. The other parts are for reading.
Lesson 1
- Strand
- Introduction To Computing
- Sub-strand
- Input and Output Devices.
- Indicator
- B8.1.1.1.2 – Demonstrate understanding of direct data entry devices
Introduction
At the supermarket, the cashier does not type the price of each item. A scanner reads a barcode in less than a second. This is direct data entry.
1. What Is Direct Data Entry?
Direct data entry (DDE): Entering data into a computer automatically from its source, without typing, using special devices.
DDE is faster and more accurate than keyboard entry because it reduces human error. It is used where large amounts of data must be entered quickly, such as in shops, banks, examinations and libraries.
2. Common DDE Devices
| Device | How it works | Uses |
|---|---|---|
| barcode reader | reads black and white lines that represent a number | shops, libraries, warehouses |
| QR code scanner | reads square patterns that store web links or data | payments, tickets, menus, mobile money |
| OMR (optical mark reader) | detects shaded marks on forms | multiple-choice exam sheets, lottery tickets |
| OCR (optical character recognition) | converts printed or handwritten text into editable text | scanning documents and books |
| MICR (magnetic ink character reader) | reads special magnetic numbers | bank cheques |
| magnetic stripe reader | reads data on the black stripe of a card | older bank and ID cards |
| chip and PIN reader | reads the chip on a card with a PIN | bank and ATM cards |
| RFID reader | reads radio tags without contact | toll payments, security cards, stock tracking |
| biometric reader | reads fingerprints, faces or eyes | Ghana Card registration, phone unlocking, attendance |
3. DDE in Ghana
DDE is common in Ghana. Supermarkets use barcode readers. Mobile money merchants display QR codes for payments. WAEC uses OMR to mark objective answers in the BECE. The National Identification Authority captures fingerprints and photographs for the Ghana Card. Some offices use fingerprint readers to record staff attendance.
4. Advantages and Disadvantages
| Advantages | Disadvantages |
|---|---|
| fast data entry | devices can be expensive |
| fewer errors than typing | damaged codes or cards cannot be read |
| reduces staff workload | may fail without power or network |
| works well for large volumes | privacy concerns with biometric data |
New words
- direct data entry
- Entering data automatically without typing.
- OMR
- Optical mark reader for shaded marks.
- OCR
- Optical character recognition for text.
- RFID
- Radio frequency identification.
Summary
- Direct data entry captures data automatically from its source, reducing errors.
- Devices include barcode and QR readers, OMR, OCR, MICR, card readers, RFID and biometric readers.
- DDE is widely used in Ghana, though it has costs and privacy concerns.
Class activity: DDE Demonstration
- Use a barcode scanner or a phone app to scan printed barcodes and QR codes.
- Record what information each code gives.
- Discuss where each device is used in your community.
You need: Barcode scanner, Printed barcode, QR-code cards, Printed RFID-reader photographs
Exercises
Answer in your exercise book first, then check your answers.
1. Which device reads shaded answers on BECE sheets?
- A. OMR
- B. MICR
- C. keyboard
- D. speaker
Show answer
Answer: OMRMark reader.2. Bank cheques are read using…
- A. MICR
- B. OMR
- C. RFID
- D. QR codes only
Show answer
Answer: MICRMagnetic ink.3. Direct data entry reduces typing errors.
- A. True
- B. False
Show answer
Answer: TrueAutomatic.4. A reader that identifies people by fingerprints is a ______ reader.
Show answer
Answer: biometricBody features.5. Name four direct data entry devices and one use of each.
Show answer
Answer: Barcode reader: shops; OMR: exam sheets; MICR: cheques; biometric reader: Ghana Card.Any four.6. Explain one privacy concern about biometric data.
Show answer
Answer: If fingerprint or face data is stolen or misused, it cannot be changed like a password, putting people at risk.Permanent data.
Lesson 2
- Strand
- Introduction To Computing
- Sub-strand
- Input and Output Devices.
- Indicator
- B8.1.1.1.3 – Examine the uses of the output devices:
Introduction
Output devices let computers communicate with us. Modern output devices go far beyond screens and printers: some print solid objects and others vibrate on your wrist.
1. Display Devices
| Type | Features | Uses |
|---|---|---|
| LCD (liquid crystal display) | thin, uses a backlight | computer monitors, TVs |
| LED display | LCD with LED backlight, brighter and energy-saving | monitors, TVs, billboards |
| OLED | each pixel lights itself, very thin, rich colours | smartphones, high-end TVs |
| touchscreen | both input and output | phones, tablets, ATMs |
| projector | shows images on a wall or screen | classrooms, churches, cinemas |
2. Printers and Other Output Devices
| Device | Use |
|---|---|
| inkjet printer | colour printing of photos and documents |
| laser printer | fast, sharp printing of many pages |
| 3D printer | builds solid objects layer by layer from plastic |
| plotter | large drawings such as maps and building plans |
| speakers and headphones | sound output |
| haptic devices | output through touch, such as phone vibration and game controllers |
| wearable displays | smartwatches and smart glasses |
| actuators | motors that make machines move, as in robots |
3. Choosing Output Devices
The choice of output device depends on the user and the task. A teacher showing a video to a large class needs a projector and speakers. An architect needs a plotter. A person who is blind needs speakers with screen-reading software or a Braille display. An engineer making a prototype may use a 3D printer.
4. Advantages and Disadvantages
Screens give instant, changeable output but use electricity and can strain the eyes. Printers give permanent hard copies but cost money for ink and paper and create waste. 3D printers can make custom parts quickly but are slow for large items and use plastic. Weighing these points helps users choose wisely.
5. Output Devices and the Environment
Output devices use energy and materials. Choose energy-saving LED screens, switch off monitors and printers after use, print only when necessary and on both sides of the paper, and recycle used ink cartridges and old devices at approved centres. These habits reduce electricity bills and e-waste.
New words
- OLED
- A screen in which each pixel produces its own light.
- 3D printer
- A device that builds solid objects layer by layer.
- haptic
- Relating to output through touch.
- actuator
- A device that produces movement.
Summary
- Display devices include LCD, LED, OLED, touchscreens and projectors.
- Other output devices include printers, 3D printers, plotters, speakers, haptic devices and wearables.
- Choose output devices according to the user and the task, weighing advantages and disadvantages.
Class activity: Output Device Study
- Study printed photographs of output devices, including wearable displays.
- Classify each as visual, sound, touch or physical output.
- Present one device and its advantages and disadvantages.
You need: Computer monitor, Printer, Printed photographs of wearable displays
Exercises
Answer in your exercise book first, then check your answers.
1. Which device builds solid objects?
- A. 3D printer
- B. projector
- C. speaker
- D. monitor
Show answer
Answer: 3D printerLayer by layer.2. Phone vibration is an example of…
- A. haptic output
- B. visual output
- C. sound output only
- D. printed output
Show answer
Answer: haptic outputTouch.3. A touchscreen is both an input and an output device.
- A. True
- B. False
Show answer
Answer: TrueShows and accepts touch.4. A screen in which each pixel lights itself is an ______ display.
Show answer
Answer: OLEDOrganic LED.5. Name four output devices and one use of each.
Show answer
Answer: Projector: classes; laser printer: documents; speakers: sound; 3D printer: prototypes.Any four.6. Which output device would you recommend for a blind learner and why?
Show answer
Answer: Speakers with screen-reading software or a Braille display, because they present information through sound or touch.Accessibility.
Homework
- List the direct data entry and output devices you see in your community in one day.