Design of Traffic " Signal Timing "

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Electrical Fault Calculation | Sequence Impedance

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reference
electrical4u.com

Grounding - IEEE standards

IEEE Grounding -standard Download

Why Microcontrollers ?

Microcontroller is one of the most hated subject of any engineering student (hope DSP always ranks 1st)...

The reasons are many...

May be the lack of knowledge of the lecturer.....

Failing in creating interest among the students.....or Simply going only through the text rather than showing the wonderful application side of the same...

Personally i too hate the subject until I got a chance to work out my project in this field..........

I am not a mega-mind in this field, but of-course i believe i can help you making a small interest :-)

The first thing you want to keep in mind is

 “Embedded system is full of fun, it will be very easy if you give a lil interest “””

The world of uP  

The micro-controller is not at all a difficult branch and you need not want to swallow embedded systems text book to start a project or making a project 100% successful (from my personal experience ).

But I must tell you, you should be somewhat good in your C language and should know the very basics.

The uP which am familiar with is, Microchip's PIC16F series

they are cheap and reliable and has inbuilt protection systems...so if you make some mistakes also it can survive.

I done most of my projects in PIC16F877A which is my personal favorite (not for me but for most of them).

In India, it’s available for Rs.150…and this is a very powerful electronic device you had ever seen 

( lil exaggerated…hope you won’t mind).

I will start discussing you d basics with coming post.....em not good @ teaching....lemme try :-)

MikroC Project - USB HID

What is USB HID?

HID is a USB device class that describes human interface devices such as keyboards, mice, game controllers and alphanumeric display devices. The USB HID class describes devices used with nearly every modern computer. Great set of existing predefined functions allow hardware manufacturers to design a product to USB HID class specifications and expect it to work with any software that also meets these specifications. In other words, no drivers are needed for USB device to work on any computer and on any operating system.

    

Let us show you how easily mikroC PRO for PIC handles with rather complex programs using the power of integrated libraries.

The following PIC C compiler code sample is a simple loop that demonstrates the operation of USB HID library. It constantly checks for HID packets, and as soon as the HID message arrives, it is transmitted back with the same content.

Examine these lines to see how the HID library deals with a highly complicated task of HID USB communication. mikroC PRO for PIC spares you the research of how USB communication works, and encapsulates everything in a simple and easy-to-understand functions.

HID Library Example

unsigned char readbuff[64] absolute 0x500;  // Buffers should be in USB RAM

unsigned char writebuff[64] absolute 0x540;

char cnt;

char kk;

void main(void){

  ADCON1 |= 0x0F;                         // Configure all ports with analog function as digital

  CMCON  |= 7;                            // Disable comparators

  HID_Enable(&readbuff,&writebuff);       // Enable HID communication

  while(1){                               // USB servicing is done inside the while loop

         USB_Polling_Proc();               // Call this routine periodically

         kk = HID_Read();

         if(kk != 0){

           for(cnt=0;cnt<64;cnt++)

                 writebuff[cnt]=readbuff[cnt];

           HID_Write(&writebuff,64);

         }

  }

}

courtesy : Mikroe.com

How Torrents Work

Today Torrent are the most common word used across whenever there is a talk about downloading a movie, TV program series or any big file like software etc. A torrent file is nothing but a file that consists of the address and information about file of interest. So,  what is torrent, how torrent became famous, how they increase the speed of downloading without affecting the bandwidth and how it is different from the traditional downloading. Let’s see,

Getting started with torrent:

1). Download the software: The foremost step taken by the user is to download and install a piece of software called as BitTorrent client who will track the torrent file’s related computers. We will discuss it afterwards, there is variety of software available for torrent tracking like utorrent, BitTorrent, BitComet clients etc.

2). Find the desired torrent file: Whichever type of file you desired to download, download it. To download a torrent file is very easy. Go to very famous websites like Bittorrent.com, torrentreactor.com or you can just make a search on search engines typing your desired file name followed by the word “torrent”. Remember, the torrent file is very small in size. It is not a data file but a file having tracking information of the data. Its extension is *.torrent.

3). Take the torrent into the torrent software: If you have successfully installed the software from the first step, you now have to just double click the torrent file and it will automatically open in the BitTorrent software.

How It Works?

Now, it’s time to see how the software is fetching the data. The torrent file works on the method of peer to peer sharing downloading method i.e. file is downloaded in different pieces according to their availability. To understand this downloading scheme, let’s go through the following steps:

1). The server consists of the data which a user wants to download. Let us assume that you want to download a movie.

 

2).  The file is being present on the server and is being getting downloaded by different computers in different parts earth. As well as there are also computers which already have finished downloading the movie. Now as stated above, the different computers consists of different pieces of same file. Like a user in North America have completed downloaded first half an hour of the movie and another person in Srilanka have downloaded some middle part of the movie. Similarly single file from server is getting downloaded between different users in pieces.  So, every user has some part of the file.

3). Now it’s your turn to download the file, the software you have installed will scan or track the computers that have pieces of the file or complete file and starts downloading from that computer’s hard drive. In simple language, the computer consisting of pieces of file acts as the server for your computer. The file is downloaded in pieces from different computers hence the bandwidth is greatly reduced.

4). The speed of download depends upon the number of computers that are ON and downloading the file. AND the computers that have finished the downloading should seed the data so that others can download it.

General Terms Used in Torrents:

There are different terms that are being used by the torrent and you will come across. They are being stated below:

Seed: Well, if you will go through downloading a torrent file from any website, you will come across the comments which state “Please Seed” or any similar sentence. Seed are the computers which have already finished downloading the whole file and seeding the data. Your computer is receiving files from them.

Peers: Peers are the computers which do not have the entire file but contains different parts of the file you are downloading.

Leeching: The user which does not seed but immediately disconnects after finishing the download and not allowing other users to download the file is called leeching. It decreases the speed of download.

Tracker: As you put the torrent file in the software, it asks to tracker to find the computers which are seeding or have small portion of the file (peers)

Swarm: Swarm is the term given to the set of all the computers that are detected or tracked by the tracker. The higher the number of computers in swarm more is the downloading speed.  

Up Limit: The up-limit or upload limit is the limit at which computer is seeding or providing data to other computers which are downloading the same file. It is generally very low (in few kbps), this is for the account that many small uploads from different computers combine together to form a large file which is then shared to other computers.

Create Your Own Torrent:

To share large files with people or with friends on the net, you can create your own torrent file. It is very easy. The software used here is utorrent. You can download it from its official website. Go through the below steps.

Step 1: Open your utorrent software and go to File>Create new torrent.

 

Step 2: A window will pop-up as shown below. You are required to fill in some information. Go on reading next step.

Step 3: Choose the file or directory you want to share and do the settings as shown in below figure.  

Step 4: Click select and save button at bottom and you are done. Next step is to send to people you want to send or you can upload it to any website for public usage.  

reference n credit

engineersgarage.com

PIC Microcontroller Programming in C

Introduction
Programming Micro-controllers
The PIC16F887 uC
Examples
Using Analog to Digital Converter (ADC)


courtesy : MikroElectonika
               www.mikroe.com

Higgs Boson Unmasked by World's Biggest Test Instruments

Two papers in the 17 September issue of Physics Letters B formally report independent discoveries of a particle that looks like a Higgs boson, walks like a Higgs boson, and quacks like a Higgs boson. The papers cautiously venture only that the particle is “consistent, within uncertainties, with expectations for the standard model Higgs boson”: It has a rest mass of about 125 GeV (gigaelectronvolts), no electrical charge, and a spin different from one. (For the record, the Intrade Prediction Market declared the Higgs boson found on September 12 and paid off its Higgs positions.)

It’s been a long road. Planning for the two experiments—the papers are from the ATLAS andCMS consortia— started in the 1990s, long before CERN’s Large Hadron Collider was built. Over the years, the project rosters have included more than 7000 scientists, engineers, technicians, and other collaborators. Each paper opened with a dedication to contributors who “did not live to see the full impact and significance of their experiment.”

Each paper is the result of a separate experiment, depending on a different detector—each of which is among the biggest, most complex, most expensive instruments ever built.

So the papers’ publication throws a spotlight (or, more accurately, a 7 TeV volt proton beam) on the two general-purpose detectors used at the Large Hadron Collider (LHC), itself the largest machine ever built, a 27-km-circumference ring tunneling 100 meters under the French-Swiss border near Geneva.

The detectors are big. ATLAS (A Toroidal LHC Apparatus, illustration above; note the two small figures standing on the barrel) is the larger of the two: 46 meters long and 25 meters in diameter. Think of something about as long as the Statue of Liberty is tall from the top of the pedestal to the tip of the torch, but a lot bulkier. ATLAS could fit inside the Lincoln Memorial, but it wouldn’t have a lot of room to spare.

CMS (Compact Muon Solenoid), the smaller detector, is 21 meters long and 15 meters in diameter. That’s roughly the size of a 2x3x3 stack of school buses.

Though different in detail, both instruments follow the same general plan. They are built as nested sensor cylinders, like a series of tin-cans-within-tin-cans, ranging from the size of a shoe-box near the core to basketball-court size at the outer limits. The detectors are symphonic variations on a theme by Rutherford and Einstein: incident particles strike a target material, throwing off a shower of particles; the shower particles strike a secondary material, stimulating emission of photons or electrons; the photons or electrons energize a sensor (a diode, a fiber optic cable, or a copper wire) to produce a signal, and mark the time, position, and nature of the original strike.

Both machines must be designed for ridiculously demanding environments—the sine qua non is ultrafast and ultra-accurate logging and triage of billions of events per second in a typhoon of radiation under magnetic fields otherwise found only in MRI machines.

ATLAS (A Toroidal LHC Apparatus) Experiment

As noted, ATLAS is the bigger of the two instruments, half an American football field long and eight stories tall.

ATLAS has three main sections—an inner detector, a pair of calorimeters to measure particle energies, and a muon spectrometer—assembled on two of the world’s largest electromagnets and tied together by a data-processing system that catches and interprets a many-petabyte-per-second flood and throttles it down to a manageable one petabyte per year.(Click here for a video tour.)

Enmeshed in the outer parts of the detector are two massive electromagnets, a five-ton, 2.4-meter-diameter, 2-Tesla solenoid and an 830-ton, 20-meter-diameter, 4-Tesla toroidal barrel magnet. These intense fields curve the paths of charged particles. Interactions with the various sensor layers yield information on position, time, and the energy of individual interactions (like tracking a cannonball through a cornfield by watching the tassels wave). Tying the individual data points together over time gives the particle’s trajectory, and the curve reveals charge, mass, and velocity.

Inner detector. ATLAS’s inner detector (image at right) is an array of sensors that measure the momentum of each charged particle.

First comes the pixel detector, (see Spectrum's description)  about the size of a jeroboam of champagne (or, for those of us of more modest means, a couple of five-gallon paint cans), three nested cylinders containing 80 million bipolar diodes designed to weather intense ionizing radiation. 

Next comes the 7-meter-long semiconductor tracker. This medium-range system wraps the pixel detector in eight layers of silicon microstrip detectors that log momentum, impact parameters, and position, streaming 6 million channels of data.

Then comes a transition radiation tracker, a sheath of some 350 000 “soda straw” sensors— 4-mm-diameter tubes filled with a mixture of xenon, carbon dioxide, and oxygen, with a gold-plated wire running down the axis. A pion or electron hitting the gas mixture sends out a shower of photons, which in turn kick out electrons. The electrons produce a current in the axial wire—more for an electron, less for a pion—proportional to the particle’s momentum. The system tracks multiple strikes along the particle’s path, and the path’s trajectory betrays its momentum.

Calorimeters. A two-stage calorimeter encloses the inner detectors, measuring the particle energies.

The inner layer, the electromagnetic calorimeter, measures the energies of photons and electrons. It consists of pleated baffles of lead and stainless steel, with liquid argon filling the gaps. Again, a particle striking the metal throws off a characteristic shower of particles, which stimulate photons in the argon and produce currents in a copper grid. The researchers can log the interactions along a particle’s track and add up the energies of the emitted photons to calculate the total energy.

The outer hadronic calorimeter measures the tracks and energies of protons, neutrons, and mesons. These are steel sheets interleaved with scintillating plastic tiles. Once again, the system detects the light from the particle shower and adds it up to find the energy of the original hadron.

Muon spectrometer. Only muons and neutrinos make it out of the hadronic calorimeter alive, and the muon stops here. These particles (with the same charge and spin as an electron, but 200 times heavier) arc through the detectors' soda-straw sensors (similar in design to those used in the transition radiation tracker), freeing electrons along their routes. The electron clouds drift to the straws’ sides and axial wires. The researchers log the resulting currents and can map the drift times back to reconstruct the particle path and energy. (Neutrinos almost never interact with anything: researchers have to infer their masses and energies the way bank examiners find embezzlements—they add up what they find in the till and subtract it from what they had to start with.)

Data System. Overall, ATLAS produces about 23 petabytes of raw data per second. The ATLAS data processing system makes the analysis a little easier by doing a lot of filtering on the front end. It uses a multi-stage triage process to reduce the data-stream from a billion or so events-per-second  to a hundred or so candidates qualified for further analysis—which still adds up to a petabyte a year.

There is a Level 1 Trigger that cherry picks information from the energy and muon detectors, deciding in about two microseconds (and that includes transmission delays) what to trash and what to pass on. Events that make it through Level 1 are cached for a fraction of a second, then passed on to the Level 2 and Level 3 Triggers, which further winnow the crowd. Overall, these filters reduce the incoming data to about a 1 KHz flow, with a tolerated latency up to 10 milliseconds.

Compact Muon Solenoid (CMS) Experiment

The Compact Muon Solenoid (CMS) detector (image below) follows the same general plan, with pixel (image at left) and silicon tracker sensors near the beam axis (in fact, both detectors use the same pixel sensor design), followed by electromagnetic and hadronic calorimeters, all wrapped up in the iron cocoon of the muon detector. (Click here for an animation of CMS detection strategies.) Though smaller than the ATLAS detector, the CMS device is considerably heavier: at about 15,400 tons, it is almost exactly twice as heavy as ATLAS. (Each of CMS’s 36 muon detector segments alone weighs in at almost 29 tons.)

CMS’s construction strategy was novel. Instead of being assembled down in the cavern, it was built on the surface, in 15 slices that were then lowered into place. This let the team start fabricating the CMS while tunnel excavators were still at work.

The magnet strategy is different, too. The solenoid that gives the experiment its name--CERN confidently calls it the largest superconducting electromagnet—is a single tube, with no toroidal barrel magnet running through the muon detector. The 4-Tesla solenoid is 13 meters long and 7 meters in diameter (almost three times the diameter of the ATLAS solenoid). Think of it as an MRI big enough to give a sperm whale a full-body scan.

Instead of pleated metal and liquid argon, the CMS electromagnetic calorimeter uses a swaddling of transparent lead tungstate crystals—75,848 of them. Each 2.5 by 2.5 by 23 centimeter prism weighs about three pounds and took two days to grow in Russian and Chinese factories. The lead tungstate scintillates when struck by electrons and photons. Avalanche photodiodes (APDs) catch the light and amplify the signal. (On the top and bottom of the lead-tungstate “can,” the radiation is too high for the silicon-based photodiodes, so CMS uses vacuum photodiodes.)

courtsey

Images: CERN, CMS/ATLAS

POSTED BY: DOUGLAS MCCORMICK