Unit 2: Input and output devices [Cont.]

Output devices
What are output devices ?
They are hardware that are used to get out the information from the computer. There are many various kinds of them. They sent out information in different ways. Moreover they have their own special purpose. In addition each of them have its own disadvantages and advantages.

Different types of output devices.

CRT (Cathode Ray Tube) monitor: it uses the cathode ray tube to display the information on the screen. This kind of monitors are still being use in the design industry because of their bright and clear screens. This type of monitor is an old version of what we use today.

CRT monitor

Advantages:

Bright, clear display.
Cheap
Display text, graphic and photos.
Reading documents on screen saves paper.
A wide viewing angle.

Disadvantages:

Large and heavy.
Being replaces by TFT screens
Not suitable for people with visual disabilities.
Use lots of power, increase cost while running.

TFT (Thin Flat Transistor): They are mostly use in home and office for computing issues. This kind of monitors are slowly replace the CRT monitor because of its new design and its advantages.

TFT monitor

Advantages:

Lighter and thinner than CRT monitors.
Cheaper than CRT
Use little amount of power.
Modern screens can also incorporate touch technology.
Can be wall-mounted.

Disadvantage:

Early models had a limited viewing angles and could blur when showing moving images.

Inkjet printer

Inkjet printer: Often used in the home to print high quality text, graphics and photo.Used to print digital photography and small amounts of documents.

Advantages:

Printers and cartridges are cheap to purchase, also it runs on small amount of it.
Modern printers often include built-in scanners and card reader.
Prints out high quality graphics and photos.

Disadvantages:

Ink cost are expensive when large numbers of pages are printed.
Slower than laser printers.
Ink cartridges runs out quickly.
Suitable for home or small office use.
Output quality depends on the type of paper used.

Laser printer: Used in organisation to print text, graphics and photos quickly and with high quality. Ideal for color reports, newsletter or poster.

Advantages:

Toner cartridges are designed to print large amount of pages.
Prints high quality images.
Process quicker than inkjet printer.
less noise when printing.
No danger of spillages due to power- based cartridges.

Disadvantages:

Expensive
Must be kept in a proper temperature.
taken care properly.

Laser printer

Laser printer toner and cartridges

Dot matrix printer: These printers uses a printer head and ribbon to generate characters on continuous stationery. They are often used in industry to print payslip, labels and invoices.

Advantages:

Good for repetitive printing task.
Running cost are very low.
Hard-wearing; suitable for factory environment.
Suitable for use with NCR or carbonless paper to create 2 copies of the same document without re-printing.

Dot matrix printer

Flat bed plotter: A large format printer that mechanically controls pen to draw an outline. They used turtle graphics program. They can move in any direction.

Flatbed plotter

Drum plotter: A large format printer with a pen that moved in a single axis track and the paper itself moves on a cylindrical drum to add the other axis or dimension.It is smaller than a flat bed plotter.

Drum plotter

Both of the plotters have the similar advantages and disadvantages.

Advantages:

Can produce printout far larger than standard printers can make.
Drawing can be produced to an exact scale.

Disadvantages:

Limited colored pen choices.
Unable to create photographs or full color graphical images.
Large-scale inkjet are often replacing this type of printer.

Multimedia projector: It is connected to the computer, television or media player to present information.It is mostly used in schools, universities and business conferences.

Multimedia projector

Advantages:

Portable
Able to produce a larger displays than monitor.

Disadvantages:

Although it's portable, it still requires an external power resource.
Requires a darken room to produce a clear image.
Space is needed to project upon.
LAmps are expensive to replace.

Speakers: Output audio information to a user as speech, music or sound effect. they are used in many devices such as TVs, radio, computers and headphones.

Speakers

Advantages:

Available in many different shapes and sizes.
Able to output information to very large amount of audiences.
Long lasting due to their simple construction.

Disadvantages:

Unsuitable for those with hearing difficulties.
Older computer requires a sound card to convert digital information to an analogue format.

Extra:

The important things that you should consider before buying an input device.

The most important thing about choosing the input devices is the purpose of using it. Also do not forget to think about the advantages and disadvantages of each devices. There are many different kinds of input devices in this world, some of them have very similar functions so you need to think very carefully before buying them.

Speed of input: how quickly can information be input or the device used?
Relevance to application: Is the right device being used for the right task?
Cost: Specialist equipment can be expensive?
Accuracy of input: Can fine detail or precise movements be recorded?

Control Device

What are control device?

A control device is a piece of hardware that are inside the computerised devices and any types of machines. Their jobs is to control the main system of that devices or machines. There are various types of control devices which are uses for numerous kinds of purposes.

Motors: often uses for creating movement for the computerised devices or machines such as robot arms, automatic doors etc. Many industries use the motors to control and move the industry machines. The motors are very accurate and can repeat the same actions accurately. They can also be uses to move enormous equipments e.g. a crane.

Buzzers: providing instantly clear sound signal or alarm for example. when the time is over, when it detecting some smoke, etc. They have very simple uses and the small size buzzers can be connected with many different types of devices.

Lights and Lamps: uses to light up something or certain areas e.g. streets, homes, offices, etc. The lights and lamps make the us see better in the dark and they can also be uses as siren or alarm. They are able to replace the sunlight for the plants in the automated greenhouses.

Heaters: mostly uses in computer-controlled green houses, automatic washing machines and computer-controlled central heating systems. Some heaters also have cooling systems which can be places in a room to maintain the regular room temperature. Likewise, the heaters can create a suitable temperature for the plants in the greenhouses.

What is an Turtle Graphics?

Turtle graphics is an instruction that are uses to programmed the computerised machines such as robots by using a series of different commands.

Turtle graphics commands

How computer stores data ? Facts & explanations.

Computers are electrical devices.
Computer have electrical signals [currents] running through the hardware.

Computers are electrical devices which mean that they need electrical signals or electrical currents to run through the computer hardware in order to start up their systems.

Computer are also digit devices [digit are numbers]
Human use a decimal number system [Powers of 10] with the numbers.0,1,2,3,4,5,6,7,8,9
Computers use a binary number system [Power of 2] with the number 0 and 1.

Computers use digits to understand information. They don't understand our languages. Humans use decimal number system (the numbers 0-9 and write them in different orders to represent different numbers e.g. 4536,473,343, etc. Those numbers are use over and over again) to count or representing information. Also do you know why do we have only 0-9 numbers, this is because we have 10 fingers on our hands!! However they convert information into into digital forms by using the binary number system(use only two numbers: 0 and 1). We can represent this as the computer language.

Binary number represents electrical signals.
The number 0 means no electrical signals.
The number 1 means electrical signals is running.

Binary number systems works by sending out electrical signals and stop sending it. '0' means no electrical signals. '1' means there're electrical signals running through the circuit.

Each binary number is called Binary digit [Bits]
Bit is the smallest measurement of the amount of data inside the computer systems.
There are 8 bits in 1 byte of a storage.
Everything in the computer is able to converted into a binary code.

There are 8 Bits in 1 Byte of storage e.g. 01101011 = 8 numbers = 8 Bits = 1 Byte. Everything in the computer is able to converted into a binary code. For instances Letters, space, shift or even the colors and graphics that are displayed on the computer screen. Overall, everything that is in the computer has its own binary code.
*Note*

To make sure you know every single detail on this topic i would like to explained why humans uses a decimal number system. Since it is devastatingly complicated for humans to remember all of the computer Bits, hence to make it easier to remember we break up the 8 Bits into 4 digits e.g. from the numbers 01101010 we break up into 0110 and 1010. Those 4 digit numbers are called Nibbles.

Units of computer storage:

1 KB (Kilobyte) = 1024 Bytes >> 1000 Bytes

1 MB (Megabyte) = 1024 KB >> 1000 KBMB

1 TB (Terabyte) = 1024 GB >> 1000 GB

1 PT (Petabyte) = 1024 TB (biggest measurement of computer storage) >> 1000 TB

* We often changed the number 1024 into 1000 because the number 1000 is easier to remember *

Files type
A generic file type is a simple type of file that can be opened with many different programs. For example .txt (This one is the simplest one with small capacity), .rtf [Rich Text Format] and .csv [Comma Seperate Value]. Different types of file have their own special jobs. For instance .csv are used in database, spreadsheet and tables.

List of different kind of files

Types of font

There are 2 types of font which many fonts are based on. There are san-serif and Serif. The Serif font is a decorative text but the San Serif font is a just a simple plain font. * In french the word "San" means without. Therefore San serif means without serif.

Actuators

All of the input devices that we have learned [ From the previous page] are all " Digital device". This means that the computer understands the information with binary number. In contrary, there are also some devices that doesn't give data as binary numbers. These devices are called " Analogue device". Here are some examples: Pressure sensor, light sensor and temperature sensor. These device detect data from wave format, which means that the sensor detects vibration.They gather data from real world therefore computer don't understand it. They would needed an ADC [Analogue Digital Convertor] to convert the data so the computer understand. It changes the data into binary number. There are also a convertor that converts binary number into an action that is worked by the actuators, which are called DAC [Digital Analogue convertor].

Output devices can also be separate into 2 types: Digital such as monitor and printer. They both present data as binary numbers. The another type is called analogue device. They are also called "Actuators" which means that the device do something or act something

List of sensors	What it detects	Images
Water Level sensor	Detect how full or how empty a container is.
Proximity sensor	Detect how close or how far something is.
Light sensor	Detect light and dark.
Moisture	Detect dampness and dryness.
Temperature sensor	Detect heat
Movement or motion sensor	Detect movement nearby.
Pressure sensor	Detect pressure e.g. if someone is standing on it.
Switch or button sensor	Detect if something is pressing or touching it.

List of Actuators	What can it do?	Images
Light bulb or LED	Creates light.
Buzzer, Bell and Siren	Creates noise.
Pump	Pushes water or air through the pipes.
Motor	Spins things around.
Heater	Increase temperature.
Cooling unit	Decrease temperature.