Printing steps of 3D Printer

Printing steps of 3D Printer
1	A design is made using CAD software
2	A software makes it in format acceptable to printer
3	3D printer is setup to allow printing
4	A solid object is built up layer by layer mainly 0.1 mm thick
5	Object is removed from printer and made ready for use

Scanning steps of 2D Scanner

Scanning steps of 2D Scanner
1	Cover is raised, Document  is placed on glass and cover is closed
2	Document is illuminated with light
3	A scan head scans the page and send image to a lens using a series of mirrors
4	The image falls on Charged Couple Device (CCD) made up of light sensitive pixels.
5	Each pixel creates an electric charge when light falls on it, which means image is changed into electronic form
6	A software produces digital image from electronic form

Printing steps of Laser Printer

Printing steps of Laser Printer
1	Data is sent to driver of printer
2	Driver checks if format is acceptable
3	Driver then checks the status of printer, whether it is in ready status
4	Data is then sent to printer’s memory, buffer
5	Printing drum is positively charge, A laser beam scans across it leaving negative charge in areas matching the text to be printed
6	Drum is coated with positively charged tonner (powdered ink) so it sticks with negative charged areas.
7	Negatively charged sheet is rolled over the drum
8	The tonner on drum sticks to paper to print text/image exactly the one sent to printer
9	Charge on paper is removed to prevent paper sticking to drum
10	Paper is passed through fuser which is set of heated rollers to melt ink and permanently fix it to paper
11	A discharge lamp removes charges from drum to make it ready for print

Printing steps of Inkjet Printer

Printing steps of Inkjet Printer
1	Data is sent to driver of printer
2	Driver checks if format is acceptable
3	Driver then checks the status of printer, whether it is in ready status
4	Data is then sent to printer’s memory, buffer
5	Printer checks whether paper is available
6	The print head moves across the paper printing data by spraying ink droplets
7	At the end of each pass the paper is advanced to next line and so on until end of the page.
8	If buffer has more data then steps from stage  5 through 7 are repeated
9	When buffer is emptied an interrupt is sent to processor, the whole process is repeated until the whole document is printed

Image Scanner

	Scanner
Properties	- Scanner is used to enter info from paper to computer -converts hard copy into digital
Uses	-“ Scanner” is used to scan hard copy into computer -old photos and important docs can be scanned
Advantages	-fast scanning as compared to typing -easy to store images in computer -easy to update stored a image
Disadvantages	-scanned images have less quality than original -They take much disk space -they take a lot of space

Graphics Tablet

	Graphics Tablet
Properties	Used by artist to create and store digital images -It is just like drawing an image of digital type
Uses	Graphics Tablet is used to draw images
Advantages	-easier to draw images -produces accurate drawing -suitable for countries where images are used instead of text e.g. Japan and China
Disadvantages	-expensive when compared to mouse -Can not be used for other inputs like text or clicking etc

Media Access Control Address or MAC

Media Access Control Address

1. MAC Address is Hardware/physical address
2. “MAC Address” is Unique address/number associated (with network card in) a device/computer
3. MAC Address is Usually 48/64 bits (12/16 hex digits)
4. First 6/8 digits = manufacturer code/id of device (nic)
5. Last 6/8 digits = serial number of device (nic)

Types of Free Softwares

Types of Free Softwares

Software feature	Free	Freeware	Shareware
Software source code can be freely accessed and modified as required	✓
All the features of the full version of the software are not made available; the full version needs to be purchased first			✓
The original software is subject to all of the copyright laws		✓	✓
It is possible to distribute modified versions or copies of the software to friends and family	✓

Security Steps of Browser

·       requests web server to identify itself/view the (SSL) certificate

·       receives a copy of the (SSL) certificate, sent from the webserver

·       checks if SSL certificate is authentic/trustworthy

·       sends signal back to webserver that the certificate is authentic/trustworthy

·       starts to transmit data once connection is established as secure

·       if website is not secure browser will display an open padlock/warning message

Memory and Storage Devices Video

SIM (Subscriber Identity Module)

Properties	Uses	Advantages	Disadvantages
Used in Mobile phones to store phone numbers  and messages etc.	*Used for phone Calls	*Can be changed from phone to phone *Easily Portable *Reliable (safe inside the phone)	*Cannot be used for personal data like multimedia files *Some cards are designed specific to a company only *Stop functioning if not used for a specific period

Safety Issues related to the use of ICT

There are number of  safety issues related to prolonged use of computer.

1. Electrocution
   Most ICT devices require an electricity, so there is a risk of the electrocution.

Causes of Electrocution

• Faulty equipment (bare wires etc).
• Spilling drinks over electrical equipment.
• Do not open an electrical device when you don't know how to repair.

How to Prevent Electrocution

• Use insulated wires.
• Keep drinks away from equipment.
• Report any problem in equipment to a technician.
• Do not open up an electrical device
  
  

1. Tripping over wires and cables

Trailing wires of ICT devices are easy to trip over if they are not secured or tucked away.

Causes of tripping over wires

Long trailing wires spread across a floor.

How to prevent tripping over wires

• Cover wires in cable ducts.
• Tuck trailing wires behind desks or carpets.
• Use wireless technology if possible.
  
  

1. Heavy equipment falling on you
   Some ICT devices (like monitor) are heavy and can cause injury if they fall on you.

Causes of equipment falling

• Equipment not placed securely onto desks.
• Poor quality and flimsy desks.

How to prevent equipment falling

• Make sure that equipment is positioned away from the edge of desks.
• Use strong desks/tables that can support the weight of device easily.
  
  

1. Fires

ICT devices require power from a mains outlet. If too many devices are plugged into a single plug at the same time it is possible to overload the circuit and start an electrical fire.
You need to use multiple plug sockets so you don't have to overload any single one.

Health Problems related to use of ICT

Users can suffer from health problems if they use ICT devices improperly or for long time. Some of them are:

1. Repetitive Strain Injury (RSI)
   RSI causes painful swelling of the fingers and wrist. People with bad RSI are not able to use their hands at all. RSI is caused by repetitive movements for long period. For example, using a mouse or keyboard repeatedly.
   Causes of RSI

• Working in a cramped workspace.
• Typing on a computer for long time.
• Using a mouse for long time.
• Holding the mouse incorrectly.

         How to prevent RSI

• Give rest to your hands.
• Use an ergonomic keyboard/mouse. 
• Use comfortable workspace. .
• Use a wrist rest.

1. Back and Neck Problems
   Back ache and neck ache are very painful situations. Both are caused by sitting incorrectly or using improper chairs without back rests. All these are poor postures.

Causes of back and neck ache

• Working in a cramped workspace.
• Not sitting upright in chair.
• Incorrect level of the computer screen.

        How to prevent back and neck ache

• Take regular breaks to stretch your body.
• Use adjustable chairs to adjust them according to your height.
• Sit upright against the back rest.
• Tilt the computer screen so it is set just below your eye level.
• Keep your feet flat on the floor.
  
  

1. Eye Strain and Headaches
   Staring at a computer screen for too long can strain your eyes and cause headaches.
   Eye strain can cause your vision to blur. Common causes of eye strain are screen flicker and having direct light causing screen glare
   Causes of eye strain

• Staring at a computer screen for a long time.
• Working in bad lighting.
• Using a computer screen with glare or flickers.
• Dirty screen.

          How to prevent eye strain

• Take regular breaks.
• Use LCD screens for less flicker. 
• Use an anti-glare screen.
• Ensure that room lighting is good.
• Keep the screen clean of dirt.
• Have eyes tested regularly.