What You Should Know About Online Deals

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handshake

The internet has immensely transformed the manner in which people nowadays shop for their various goods and services.

This basically implies that a shopper does not necessarily need to physically visit a wide range of shopping malls and other outlets to find the items needed and to purchase them.

This is because there are various online stores and e-shops that have been established by various vendors and service providers where shoppers can easily visit and look for the specific items needed and make a purchase.

However, there is always a concern when it comes to the price at which most of these items are sold at on these online stores. They are relatively cheap and in some cases can be acquired at much cheaper rates compared to most of the physical stores. This usually makes some people sceptical of the quality of these products and services.

It is vital to understand that there are many aspects that allow these online stores to offer the products at much lower rates. There are also many different types of sites you can save money on from auction sites like eBay and MadBid to daily deal sites like Groupon.

One reason why numerous online products are normally a lot more affordable is because the business owner does not incur too much expense in terms of paying the rent for an establishment as it would be in a local store. This enables a business to save a considerable amount of money thus making it easy for them to sell the products at a cheaper rate.

Another reason why online stores offer great deals is because this kind of an establishment does not necessarily require the owner to employ any sales or staff members. This therefore helps in ensuring that the cost for operating the business is cut, since there is no staff to be paid. All that the client really needs to do is to search for the ideal item on the website, assess it closely, pay for it and wait for it to be delivered to his or her home or workplace.

The good thing with online deals is that there are numerous online vendors that are selling a wide range of items you could be looking for. This makes it possible for the customers to get the best bargains since he or she will be able to window shop in various online outlets and certainly find the one that fits within their budget.

There is also an option for enthusiastic shoppers to subscribe to mailing lists that will allow them to get notifications and consequently know when the promotions, new arrivals, offers and auctions are taking place, so they are able to take advantage of them and obtain the ideal items at cost-effective rates.

Online auctions and daily deal sites are also advantageous because you can often acquire the items you want without even leaving the comfort of your home or workplace. This basically implies that it is a convenient method of shopping that will allow you to save a considerable amount of money and ample time that you would otherwise have been spent searching for the items in local outlets.

It also helps in reducing stress such as long queues, where to park and the painstaking search for a particular item, from one outlet to another.

February 15, 2014

Inside a Processor

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Today our whole computer system as well as every complex electronics equipments are dependable on ‘Processor‘. You are viewing this page through the help of a microprocessor or so called ‘Processor‘. A layman knows that every computer system has a ‘brain’, that is the CPU (Central Processing Unit), which has a Motherboard inside it. This motherboard consists of different electronics components, transistors, IC s, RAM, ROM and most important component is Processor. It processes the whole computer system, like calculating arithmetic problems, input/output processes in a fraction of second. You may want to know what is inside a processor? How it works? and so many questions may arrive.

Whatever, there are so many processor manufacturers in the market today. Among those, Intel is widely used in today’s world. In a processor the whole processing or computational engine is fabricated onto a single chip. In my previous post, I have talked about semiconductor device fabrication process. Intel’s first microprocessor was 4004 which was introduced in 1971. It could calculate addition and subtraction at that time and it was 4 bit processor.

 

Intel 4004 microprocessor

Intel 4004 microprocessor

 

Internal architecture of Intel 4004

Internal architecture of Intel 4004

After that by technology revolution, Intel has made core processor i7. Lets check the list of their invention.

Processor revolution

Processor revolution

Here, it is to be noted that the number of transistor and clock speed are increased as Intel brought newer processors. Depending on the number of transistor integration, we have categorized the technology into following:

  • SSI (Small Scale Integration)
  • MSI (Medium Scale Integration)
  • LSI (Large Scale Integration)
  • VLSI (Very Large Scale Integration)
  • ULSI (Ultra Large Scale Integration)

Technologists and scientists are still developing to get more and more speed in cheap. Clock speed is increasing day by day, now it is in range of 3.10 GHz with 64 bit processing speed.

To know how microprocessor works, one has to know the details on assembly language program. This is a language which microprocessor can read to complete a computation. Intel’s 8085 microprocessor was a revolutionary microprocessor in processor’s world. Let’s check what it contains:

Intel 8085 architecture

Intel 8085 architecture

It is a 8 bit processor. It has seven 8-bit registers A, B, C, D, E, H, L, where A is a 8 bit accumulator and other six registers can be used as 16 bit register like BC, DE, HL, it also has a program counter, stack pointer. These are connected to ALU (Arithmetic Logic Unit) which has the capability to add, subtract, increment or decrement the register and data from memory etc. The others are BUSes. Mainly two kinds of buses are:

  • Address bus- 8 bit wide.
  • Data bus- 8 bit wide.

These BUSes helps to carry data and signals from different portions of the device. It has a clock line that lets a clock pulse sequence the processor and a RESET line to reset the program counter to zero. There are also RD and WR lines which are used to read instructions from certain memory locations and write to memory. So memory is directly connected to RD or WR lines. Either RAM (Random Access Memory) or ROM is connected like this. It has 8 bit buses, so it can address 2^8 bit = 256 bit address. A ROM (Read Only Memory) is a read only device.

ROM

ROM

ROM

ROM

So when we give an input to the microprocessor, the program for that input tells microprocessor to fetch some instructions from the HDD to RAM and then the processor executes that program. After that by some external interface output is shown.

fig_2-17

instructioncycle

So, you have a concept now what is inside a processor and how processor works.

 

February 8, 2014

How The Internet Works?

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Internet’- the entire world is very much familiar with this word today. Internet is a global system of computer networks with server and clients which maintains some specific protocols to create a network. In simple words, internet is a network of computer networks, which is made up of computers which are connected with each other through some path and is able to communicate within themselves. Now a days, not only computers, but also, mobile handsets, camera, faxes are connected over internet. To understand what internet is, we have to consider two things. First one is: ‘Hardware’- that includes the cables (telephone cables, fiberglass etc.) that carries a large amount of information from computers to computers. Also, wireless connection communicates through satellites, electromagnetive waves (EM waves). Apart from this, some networking equipments are routers, servers etc.

internet_1

There are always some starting and end point of every networking system. The point, which stores all the information are web servers, the end point which sends request to server for accessing those information are called clients. Nodes are the connecting points between them, which are routes to connect computers. These may be of fiber optics, wireless connection or satellite based. Now a days, ‘Cloud’ has made a huge change in the internet world, by this we can store a numerous amount of information in cloud server.

There may be different networks between computers. Those are: LAN (Local Area Network), WAN (Wide Area Network), MAN (Metropolitan Area network) etc. In LAN, a number of computers are connected to each other and transmission in between any two computers within the same network is possible. In WAN, several LAN s form a network. Usually LAN covers a particular locality, MAN covers a particular city, where WAN covers the whole world network.

Local Area Network

Local Area Network

Wide Area Network

Wide Area Network

Now, we know that how networks forms, but the fact is between any two computers, there must be some set of rules or a common language that all the computers have to agree in order to start transmission. These set of rules are known as ‘Protocol’. You may be familiar with this term. The various machines (different OS like MAC, Windows and Linux) would be unable to understand each other or even send information in a suitable way. The protocols provide both the method and a common language for machines to use to transmit data.

Transmit and receiving

Transmit and receiving

There are several protocols. Such that HTTP (hypertext transfer protocol), that we use during the accessing of a website from browser. Others are FTP (file transfer protocol), MCP, UDP, ARP etc.

The most important protocols are TCP (Transmission Control Protocol) and IP (Internet Protocol) – in most cases about protocols you’ll see them listed as TCP/IP. These protocols basically establish sets of rules how information will be passed through the computers. The protocols must be used by the source computer and target computer to transmit and receive data. You may have also heard about the term- “IP Address”- it is the address hold by each machine in a network. IPV4 is a 32 bit address and IPV6 is a 128 bit address. One can locate a particular computer when to transfer a confidential file to some particular machine, not shared to all. Without IP address we couldn’t do that. This is done by packet transmission. Packets are 1000-1500 byte file transferred from server to client.

Internet connection

Internet connection

When you connect you’re a website from your web browser, the computer sends a request to the local ISP (Internet Service Provider) which again routes the request to another server again until the main web server receives the request. Then it checks if the computer is under that protocol or not. If everything is okay, then server replies back to the computer by some specific protocol which, by chaining process is received by your computer through the router and modem and you can access that website.

February 7, 2014

Electronics Waste- Its Recycling and Harmful Effect

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In today’s world, Electronics waste or E- Waste- this term for electronics product is very popular with the increasing number of electronics market. It is some electronics equipments that is non-working or obsolete and have reached the end of their lifetime. Unwanted, unusable electronic products such as computers, computer accessories like motherboard, keyboard, mouse etc, old televisions,VCR’s ,DVD Players, radio, stereo equipment, cell phones are commonly referred to as ‘electronic waste. As days are going on, the amount of E-Wastes are increasing.

Computers- E-waste

Computers- E-waste

 

Electronics circuit board

Electronics circuit board

Obsolete computers are thrown away from the whole world, millions of computers are meeting their lifetime and getting on the waste list. Not only computers, but also, televisions and cell phones and electronics circuit boards are taking part in E- Waste market. In a survey, it is known that in US only, more than 100 millions of computers are got scrapped and less than 20% of them are recycled. As the demand of electronics market is increasing day by day, the main developing countries are importing wastes from the first world countries. They are thrown on ground and those are making landfill which is really harmful as those wastes contains toxic metals beryllium, cadmium, mercury and lead. Those are when treated by environment, the pollution occurs. In Africa, labours, who removes materials from electronics wastes do not wear any protective equipments and also they breathe in toxic chemicals environment. This includes the workers of China, India and Pakistan like developing countries. Sometimes ,many remnants of e-waste are “disposed of” via open burning.  They are not recycled. The flame retardants is very much harmful for the total animal kingdom.

Burning of E-waste

Burning of E-waste

 

landfill by E-waste

landfill by E-waste

Recycling:

Let’s first look at this video.

This time we were discussing about the problems that E- Waste creates. Now we are going to discuss about the recycling process of those wastes. So that we can get an Eco-friendly environment. Most electronic waste goes through a recycling process called WEEE (Waste Electrical and Electronic Equipment). It recycles 95-98% of the E-wastes.

ewaste

Recycling process has some steps. Those are:

  • Picking Shed: here the wastes which are shorted by quality control department are picked up.
  • Primary Size reduction process: In this step, the large e-wastes are shredded into small 100mm waste so that not only the device, but also the data included in the hard drives and memory are thoroughly destroyed.
  • Secondary size reduction: In this step, those reduced sized waste are shaken on the conveyor belt to ensure that the total waste is broken down again.
  • Magnet filtration: In this step, iron, steel and iron products are filtered and the remaining portion of the waste goes off.
  • Metallic and non-metallic contents: In this step, metallic contents- Aluminum, Copper are separated from non metallic contents.
  • Water separation method: By water separation method, plastics and glasses are separated from each other. after that the wastes are totally recycled and goes to the different industrial factory for re use.

Also, some other recyclers use other methods, but the main system is same for all.

Recycling

Recycling

We have to conduct detailed inventories of e-waste. We should aware all of our country people about the effect of E-waste and encourage them to recycle electronics wastes. we can show advertisement through television from Govt. side. So, we always have to think of our living world to keep it healthy for our generation and for the next generation. For this, we have to make e-waste recycling compulsory otherwise make it penalty through the usage of law.

 

 

February 6, 2014

Semiconductor device fabrication: Photolithography

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Today world is very much advanced with the benedictions of science and technology. In everyday life we cannot live with the help of technology, especially electronics. We are totally dependable on it. When we think of the word ‘Electronics Technology’, we think of some complicated electronic circuits connected on PCB. Those electronics circuit contains many components like resistor, capacitor, inductor and most of the time, Integrated circuits (IC). One can understand the meaning of IC by its name. It is nothing but a circuit consisting of many circuits integrated together.

 

Resistor

Resistor

Capacitor

Capacitor

Inductor

Inductor

Integrated circuit (IC)

Integrated circuit (IC)

 

Photolithography is mainly used in VLSI(Very high speed Integrated circuit Hardware description Language) design process.

Photolithography is the process of transferring geometric shapes on a mask to the surface of a silicon wafer.

In between these three main electronics component, IC is most popular today and widely used in almost every analog and digital circuits. IC fabrication is very important as well as interesting thing in electronics world. IC fabrication consists of several steps.

  • Wafer Growth
  • Photolithography
  • Doping
  • Oxidation
  • Deposition
  • Etching
  • Epitaxial Growth

Among these process, photolithography is the main and important step. Semiconductor devices and integrated circuits are formed on thin material slice, which is known as ‘Wafer‘. Another two contents are needed in photolithography process. Those are Photoresist and Transparent glass mask. In the very first, wafer is cleaned, i.e, organic, inorganic, metallic impurities are removed from the wafer surface. Then, photoresist is applied on the wafer surface.

Photoresist:

There are two kinds of photoresists available.

  • Positive photoresist
  • Negative photoresist.
photoresist activity

Photoresist activity

For positive resists, the resist is exposed with UV ray wherever the underlying material is to be removed. In this type of photoresist, the masked region is remain same, whereas the area which is exposed to UV light is dissolved into developer. So, the photoresist is dissolved.

In negative photoresist, the opposite manner is occurred. here, the area of the photoresist, which is exposed to UV ray remains same as before, and the masked part of photoresist is removed. Thus, we can draw our deserved shapes on Silicon wafer.

Mask Alignment and Exposure:

This is the most vital step in photolithography process. The transparent glass mask is a rectangular glass plate with a masked design on it. It is used to transfer the desired shape on wafer surface by the help of photoresist. Once the photoresist is alligned to the photoresist surface, this is exposed to high intensity UV ray. Then as per photoresist type, the mask design is transferred onto the photoresist surface. There are also three intermediate steps:

  1. Contact printing
  2. Proximity printing
  3. Projection printing

 

Printing processes

Printing processes

Development:

The last step of photolithography is development. At low exposure energies Et, negative photoresist element is completely soluted in the developer solution. As the exposure is increased above its threshold energy, more of the resist film remains after development.

For positive photoresists, the resist’s solubility in its developer is finite even at zero-exposure energy. The solubility gradually increases until, at some threshold, it becomes completely soluble. The complete process is Photolithography.

plithp3

 

February 5, 2014

0-99 Counter using assembly language programming for 8051- Working Perfect!!

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Today, I am going to write about an interesting micro-controller project, i.e, 0-99 counter using some delay in 8051 architecture. This is done using AT89C51 micro-controller manufactured by Atmel.

Theory is that in 8051 architecture, we can use C language or assembly level language to program what we want to introduce in the MCU(Micro Controller Unit). This is easy to program MCU in C language or assembly both of them. I have chosen assembly language for programming. The program will count from 00 to 99 in a seven segment display. seven segment display is a displaying device which contains 7 lined LED s, and 1 dot-ed LED. The lined LED s are known as -a,b,c,d,e,f,g and the dot-ed LED is h.

7 segment display

7 segment display (both common-anode and common-cathode)

7 segment display (both common-anode and common-cathode)

So when we need a certain digit to display on this device, we need to glow the corresponding LED s. Such as when we need digit ’4′, we need to glow the LED- b,c,f and g. Let’s have a look at the image below for getting the idea of digitization. I have used LED, which is vastly available in the market. The code of LED is- LT542R.
So, now have a look at the image below for getting a better understanding of how to display 0-9 in seven segment display:

0-9 display on 7 segment
0-9 display on 7 segment

So, using 1 seven segment display, we can make a counter which can count from 0 to 9, and using two seven segment display we can make a counter which can count upto 99. There must have some delay in between two corresponding numbers.

Now, lets have a look of the assembly language program of 0-99 counter:

I have programmed in a software called keil uvision 4. You can download it from their website without any charge!

You can download it here. By simply clicking on C51, you can download the development kit for 8051 MCU. Then install the software and start programming. We can program in both C and assembly language in Keil.

Program:

ORG 00H
START:  MOV P0,#0C0H                    // program for displaying the second digit
ACALL START1
MOV P0,#0F9H
ACALL START1
MOV P0,#0A4H
ACALL START1
MOV P0,#0B0H
ACALL START1
MOV P0,#99H
ACALL START1
MOV P0,#92H
ACALL START1
MOV P0,#82H
ACALL START1
MOV P0,#0F8H
ACALL START1
MOV P0,#80H
ACALL START1
MOV P0,#90H
LCALL START1
SJMP START
START1: MOV P2,#0C0H                   // program for displaying the unit digit
ACALL DLY
MOV P2,#0F9H
ACALL DLY
MOV P2,#0A4H
ACALL DLY
MOV P2,#0B0H
ACALL DLY
MOV P2,#99H
ACALL DLY
MOV P2,#92H
ACALL DLY
MOV P2,#82H
ACALL DLY
MOV P2,#0F8H
ACALL DLY
MOV P2,#80H
ACALL DLY
MOV P2,#90H
DLY: MOV R5,#215D        // delay subroutine
LABEL: ACALL DELAY
ACALL DELAY
ACALL DELAY
ACALL DELAY
DJNZ R5,LABEL
RET
DELAY: MOV R6,#2D
MOV R7,#3D
LOOP1: DJNZ R6,LOOP1
LOOP2: DJNZ R7,LOOP1
RET
END

Here 0F9H, 0C0H, 0A4H and so on… represents the hex codes of the digits(0 to 9). These hex codes are deduced by the simple rule of which LED s are to glow for a particular number. Suppose digit ’2′ is to be displayed. In this digit, in seven segment display, LED- ‘a’,'b’,'d’,'e’ and ‘g’ glow whereas ‘c’,'f’ remains off. We denote the on LED s by digit ’0′ and off LED s by digit ’1′. It is to be noted that where we need to glow the dot, we make LED ‘h’ as ’0′, otherwise, ’1′ for keeping the dot LED off. So, next step is to convert the h-g-f-e-d-c-b-a code to hex code. For digit ’2′, the hex code is A4H (H represents hex). So after calculating the hex codes, we have to send that hex code to the particular port where the seven segment display is connected.

Output:

This assembly language program is very useful for the beginners who want this counter. This is working perfectly. I have attached the video of the counter.

 

February 3, 2014