iGCSE Computer Science - Distance Learning

Tutor Marked Assignment 6
Tutor Marked Assignment 8 (Programming)

Manual Input Devices

Input devices can either be manual automatic. The automatic devices that allow us to input data into a system are often referred to as sensors and we will be looking at these and more detail in the next lesson. The devices that allow us to input data and output data back to the user but a plugged into our computer system are referred to as peripheral devices. It is important to remember peripheral devices are input and output only and do not refer to the removable storage devices or charges that we may also plug into the computer system.

Something examples of manual input devices that you are required to be able to identify and suggest for use when suitable discussed in more detail in the video and listed below:

  • Mouse
  • Trackball
  • Keyboard
  • Concept Keyboard
  • Microphone
  • Digital Camera
  • 2D Scanner
  • 3D Scanner
  • Interactive Whiteboard
  • Touchscreens
  • Barcode Readers
  • QR Code Readers
  • Graphics Tablets

As you can see this is quite a long list of devices that you need to be familiar with. As you go through the video, it is a good idea to make sure that you have created a set of flash cards so that you can practice identifying the use of each device and how it works.

Mouse & Trackball

A mouse is also known as a pointing device and controls the cursor on your screen. This input device allows the user to select objects on the screen by clicking and dragging them to move windows and other objects around.

Older mice used ball inside the device which detected movement. Unfortunately, this would become clogged with dust which affected the ability for the mouse to work and would often need to be cleaned. Newer mice use an infrared laser to detect movement and are much more accurate.

Concept mice are built to be ergonomic, that means to adapt to the human form and be more comfortable and easier to use. Examples of this are trackball mice where instead of moving the mouse, but instead a ball at the top is used to control the pointer on the screen. Other ergonomic mice include gaming mice which have additional buttons add it to them to help control the game instead of using multiple keys on the keyboard. These are often also built to be more comfortable for longer term use.

Lesson Task – Mice

Investigate why trackballs were invented and what use they have in the technology & design industry today.

Keyboards

Keyboards allow the user to enter alphanumeric data directly into the computer system and are considered one of the basic input peripherals required for the computer system to run. In fact, even before the operating system is installed the computer system will recognise the keyboard and allow the user to enter basic commands (although this often does not extend to the additional keys along the top).

Additional types of keyboard unknown his concept keyboards and include economic keyboards which are easier to use long term and help to reduce the instance of repetitive strain injury, and keyboards that are created for unusual situations like infrared keyboards in a kitchen.

Lesson Task – Keyboards

Watch the video below to find out why we don’t use an abcd keyboard. Investigate the different types of keyboard that are compatible with your computer. What type of keyboard might you use if you weren’t able to see the keys?

Microphones

Microphones maybe a standalone peripheral device or built into a different peripheral such as a headset. In whatever form they take a microphones job is to convert the analogue sound waves around it into digital data.

This conversion is performed using a component called the ADC or analogue to digital converter. The ADC measures the analogue sound waves amplitude at regular intervals, converts these measurements to binary, and saves this as digital data which can be later translated back into a sound wave using a speaker.

Lesson Task – Microphones

Use your own microphone to make an audio recording using sound editing software or this website. Create a poster showing how the sound wave was created by zooming into the sound wave and identifying the individual samples (measurements).

Digital Cameras

Digital cameras allow us to capture photographs by exposing light through a lens and converting the light that sent into the Camera body into the digital version RGB , red green blue. By converting this light into individual squares of colours known as pixels a bitmap version of the image taken is created and then saved onto a storage device within the Camera. This digital image is often saved as a raw file which can then be converted into a compressed version such as a JPEG.

The increase in use of digital cameras came about as they are loud photographs to be taken more cheaply as there is no ongoing costs of printing. The ability to share a digital image instantly awesome encouraged the introduction of embedding digital cameras into smart phones.

Digital Camers – Lesson Task

Watch the video below and create a comparrison of standard and digital cameras. How are the images captured? What are the benefits and drawbacks of each?

Touch Screens

Touch screens come in two different formats: resistive and capacitive. The older of these is resistive and is often seen in older devices like PDAs or the original version of the Nintendo DS. A resistive touch screen requires the user to use a hard stylus or fingernail which touches 2 screens together creating an electrical connection which is measured using sensors around the edge of the screen. Resistive touch screens are often found where the screen needs to be tougher such as ticket machines in public places.

Capacitive touch screens require a conductive surface to touch the screen such as a fingertip and do not work with hard styluses and fingernails. The capacitive screen uses this conductive surface to break the electrical signals that are being sent across the screen. Using similar sensors the place at which the touch screen was disrupted his measured. This more recent technology require a hard screen often using glass and is seen in most smart phones.

Lesson Task – Barcode Readers

Watch the video below about the difference between 1D & 2D barcodes. Use an online tool to make some examples of your own, then try out the QR code that you see on the Scribbl.it notes below.

Revision Task

Download, print and complete the notes document below. Remember to highlight the key words in colour and add your own notes in the areas provided.

Revision Task 2

Download the worksheets below and complete each one to show your understanding of identifying & assigning an input device to a scenario.