Various Type Of Segmented Displays-Must Know That They Too Exists..

Seven-segment display (SSD):
A seven-segment display (SSD), or seven-segment indicator, is a electronic display device for displaying decimal numerals. Seven-segment displays are widely used in digital clocks, electronic meters, and other electronic devices for displaying numerical information. 
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SSD, Front
SSD, Front

SSD, Back
SSD, Back

Vane display:

 A vane display is a type of 7-segment display. Unlike LED segmented displays, vane displays are composed of seven physical surfaces, typically painted white, but occasionally other colors, such as yellow or fluorescent green. If a segment is to be displayed as "off", it will be rotated so that its edge faces forward, with the painted surface pointing away and not visible. A segment that is to be displayed as "on" will be rotated so that the painted surface is shown.

Vane Display
Vane Display
Vane Display
Vane Display


Nine-segment display:

 A nine-segment display is a type of display based on 9 segments that can be turned on or off according to the graphic pattern to be produced. It is an extension of the more common seven-segment display, having an additional two diagonal or vertical segments between the top, middle, and bottom horizontal segments. This provides a minimal method of displaying alphanumeric characters. Basically developed for Russian Scientific Calculator.

Nine Segment Display Patterns
Nine Segment Display Patterns

Possible Shapes Of Numbers In A NSD
Possible Shapes Of Numbers In A NSD

Fourteen-segment display:

A fourteen-segment display is a type of display based on 14 segments that can be turned on or off to produce letters and numerals. It is an expansion of the seven-segment display, having an additional four diagonal and two vertical segments with the middle horizontal segment broken in half. A seven-segment display suffices for numerals and certain letters, but unambiguously rendering the ISO basic Latin alphabet requires more detail. A slight variation is the sixteen-segment display which allows additional legibility in displaying letters or other symbols.

Fourteen Segment Display
Fourteen Segment Display

Fourteen Segment Display, In Use
Fourteen Segment Display, In Use

Nixie tube:

A Nixie tube is an electronic device for displaying numerals or other information using glow discharge.
The glass tube contains a wire-mesh anode and multiple cathodes, shaped like numerals or other symbols. Applying power to one cathode surrounds it with an orange glow discharge. The tube is filled with a gas at low pressure, usually mostly neon and often a little mercury or argon, in a Penning mixture.
Nixie Tube In Action
Nixie Tube In Action

Nixie Tube
Nixie Tube

A Nixie Clock

Sixteen-segment display:

A sixteen-segment display, is a type of display based on 16 segments that can be turned on or off according to the graphic pattern to be produced. It is an extension of the more common seven-segment display, adding four diagonal and two vertical segments and splitting the three horizontal segments in half (A fourteen-segment display splits only the middle horizontal segment). Sixteen-segment displays were originally designed to display alphanumeric character.

Sixteen Segment Display
Sixteen Segment Display

Sixteen Segment Display IC
Sixteen Segment Display IC

Sixteen Segment Display, With Segment Code
Sixteen Segment Display, With Segment Code
Possible Patterns, 16 Segment Display
Possible Patterns, 16 Segment Display
image courtesy:

How RFID Works-Everything That You Need To Know!

RFID Chip, Equivalent to the size of Rice Grain
RFID Chip, Equivalent to the size of Rice Grain
RFID is an acronym for "radio-frequency identification" and refers to a technology where digital data encoded in RFID tags or smart labels are captured by a reader via radio waves. RFID is similar to barcoding in that data from a tag or label. RFID, however, has several advantages over systems that use barcode asset tracking software. The most notable is that RFID tag data can be read outside the line-of-sight, whereas barcodes must be aligned with an optical scanner. 
RFID- Reading Network
RFID- Reading Network
 A Radio-Frequency Identification system consists of 3 parts:
  • 1. A scanning antenna
  • 2. A transceiver with a decoder to interpret the data
  • 3. A transponder - the RFID tag - that has been programmed with information. 
An absolutely key part of the technology; RFID tags do not need to contain batteries, and can therefore remain usable for very long periods of time (maybe decades).

The Radio Frequency radiation does 2 things:
  • 1. It provides a means of communicating with the transponder (the RFID tag).
  • 2. It provides the RFID tag with the energy to communicate (in the case of passive RFID tags). 

RFID Tags Are Of 2 Types:-

Active Tag :

**An active tag when, it is attached with a battery or power source for the tag's circuitry & antenna. Some of the active tags available in the market contain replaceable batteries;  & others come in sealed units.

Major advantages of an active RFID tags are:
  • 1. It can be interpreted at distances of 100+ feet, thus greatly improve the mobility of the device.
  • 2. It may have other sensors attached.

The problems and disadvantages of an active RFID tag are:
  • 1. The tag cannot function without battery power, which limits the lifetime of the tag.
  • 2. The tag is typically more expensive.
  • 3. The tag is physically larger, which may limit applications.
  • 4. The long-term maintenance costs for an active RFID tag can be greater than those of a passive tag if the batteries are replaced.

Active RFID tags may have the following features:
  • 1. Longest of the range of communication of any other tag in the market.
  • 2. To perform independent monitoring and control.
  • 3. The capability of initiating communications.
  • 4. To perform diagnostics.
  • 5. To attain highest data transmission bandwidth.

Passive Tag:

A passive tag does not contain a battery. When radio waves from the reader are encountered by a passive RFID tag, the coiled antenna in the tag forms a magnetic field. The tag obtains power from it, energizing the circuits in the tag. The tag then sends the information written in the tag's memory. 

 The advantages of a passive tag are:
  • 1. The tag functions without a battery & have a useful life of 20+ years.
  • 2. Much less expensive to manufacture
  • 3. The tag is much smaller (some tags are the size of a grain of rice).

The major disadvantages are:
  • 1. The tag can be interpreted only at a very short distances, typically a few feet at most.
  • 2. It might not be possible to include sensors that use power to operate.
  • 3. The tag remains readable for a very long time, even when the product has been sold.


**When an RFID tag passes through the field of the scanning antenna, it detects the activation signal from the antenna. That "wakes up" the RFID chip, and it transmits the information on its microchip to be picked up by the scanning antenna.

An EPC RFID tag used by Wal-Mart.
An EPC RFID tag used by Wal-Mart.

RFID tags can be read in a wide variety of circumstances, where barcodes or other optically read technologies are useless.
  • 1. The tag need not be on the surface of the object (no subject to wear)
  • 2. The read time is typically less than 100 milliseconds
  • 3. Large numbers of tags can be read at once rather than item by item. 

RFID uses:

  • # Animal tracking tags, whales, dogs, cats, pets, etc
  • # To identify trees or wooden items.
  • # The anti-theft hard plastic tags attached to merchandise in stores/shopping malls are also RFID tags.
  • # Heavy-duty 120 by 100 by 50 millimeter rectangular transponders are used to track shipping containers, or heavy machinery, trucks, and railroad cars.
  • # Inventory management
  • # Asset tracking
  • # Personnel tracking
  • # Controlling access to restricted areas
  • # ID badging
  • # Supply chain management
  • # Counterfeit prevention (e.g., in the pharmaceutical industry)



RFID used inside a living body:

RFID devices that are intended to be implanted inside a living body (like an animal or human being) have special requirements. They need to be encased in a special kind of casing that will not irritate or react with the living tissues that they are inserted into. The casing must also be transparent to the scanning radio-frequency beam that activates the chip. Some RFID vendors have created biocompatible glass for use in these applications.

Note: The amount of information that the tag stores can vary. Passive tags, only store about 1024 bytes of information, or 1 kB. That will contain all the information like
full name, address, phone number, birthday, bank account number, place of birth and mother’s & father's name in only 130 bytes of information in plain text.

RFID Reader
RFID Reader

Drawbacks With RFID:

No particular RFID Standard:  There is no Global standards of RFID they are still being worked on. Its notable that some RFID devices never ever meant to leave their network (especially in case inventory control). This causes various problems.

RFID Network Can Easily Be Jammed: Since RFID systems use electromagnetic waves (like WiFi networks or cellphones), they are relatively easy to get jammed using energy at the right frequency, which is of that of operating frequency of RFID tag. Although this would only be an inconvenient factor for consumers in stores (due to longer waiting time at checkout), & more over it could be disastrous in othersituations where RFID is used intensively, like  in military or in the hospitals.

RFID Reader Collision:

Reader collision occurs when the signals from two or more readers overlap. The tag is unable to respond to simultaneous queries. Systems must be carefully set up to avoid this problem; many systems use an anti-collision protocol.

RFID Tag Collision:

Tag collision occurs when many tags are present in a small area; but since the read time is very fast, it is easier for users to develop systems that ensure that tags respond one at a time. 


Difficulty of RFID tags to get removed:

RFID tags are difficult for users to remove; some are very-very tiny(less than a a millimeter square) other types of RFID IDs may be hidden or embedded inside a product where consumers can't have a look of them. New technologies allow RFID tags to be "printed" right on a product and may not be removable at all.

RFID tags can be sensed from a greater distance with an antenna of high gain:

An antenna of high gain it can be used to read the tags from much far away distance, it can lead to certain privacy issues, thereby it may be not used in certain area..

Seven Segment Display-All You Need To Know

Seven Segment Display
Seven Segment Display, with decimal point

A seven-segment display (SSD), or seven-segment indicator, is a form of electronic display device used for displaying numbers.
Seven Segment Display Labelled
Seven Segment Display Labelled
The segments of a 7-segment display are referred to by the letters A to G, which are used to display any number between 0-9, where the optional DP decimal point (an "8th segment") is used for the display of non-integer numbers.

There can be 128 possible states of this 7 segment display, if the decimal point is not used.
128 states of Seven Segment Diaplay
128 states of Seven Segment Diaplay
In a simple Seven Segment package, typically all of the cathodes (negative terminals) or all of the anodes (positive terminals) of the segment LEDs are connected and brought out to a common point; this is referred to as a "common cathode" or "common anode" device. Hence a 7 segment plus decimal point package will only require nine pins. But it may vary in other commercial products, that are made as per consumer specifications.

Equivalent Circuit Of seven Segment Display When connected to a power Source:
Equivalent Circuit Of seven Segment Display When connected to a power Source
Equivalent Circuit Of seven Segment Display When connected to a power Source
To  common Anode pin we connect the resistor of 470 Ohms & this resistor to the power supply +5V. This amount of voltage is sufficient to drive your seven segment display.

NOTE: In order to avoid burnout of your SSD, you should connect the power / voltage source with the current limiting resistor, which will ensure that the current is not exceeding 15mA(Max. allowable current through it)[refer data sheet for accurate knowledge of Max. allowable current for your SSD, as its materiel dependent]

Hexadecimal Codes Using Seven Segment Diaplay:
Through a Micro-controller output, a single byte can encode the full state of a 7-segment-display. The most popular bit encoding are "gfedcba" and "abcdefg", where each letter represents a particular segment in the display. Example, in the "gfedcba" representation, a byte value of 0x06 would (in a common-anode circuit) turn on segments 'c' and 'b', which would display a '1'.

Different Hexadecimal Codes, Using Seven Segment display

Hexadecimal encodings for displaying the digits 0 to F
Digit gfedcba abcdefg a b c d e f g
0 0×3F 0×7E on on on on on on off
1 0×06 0×30 off on on off off off off
2 0×5B 0×6D on on off on on off on
3 0×4F 0×79 on on on on off off on
4 0×66 0×33 off on on off off on on
5 0×6D 0×5B on off on on off on on
6 0×7D 0×5F on off on on on on on
7 0×07 0×70 on on on off off off off
8 0×7F 0×7F on on on on on on on
9 0×6F 0×7B on on on on off on on
A 0×77 0×77 on on on off on on on
b 0×7C 0×1F off off on on on on on
C 0×39 0×4E on off off on on on off
d 0×5E 0×3D off on on on on off on
E 0×79 0×4F on off off on on on on
F 0×71 0×47 on off off off on on on

One Mode Equivalent Circuit Of a Seven Segment Display
One Mode Equivalent Circuit Of a Seven Segment Display, Common Anode & Common Cathode

BCD to 7-Segment Decoder c/w 4-bit Latch

Connection & Pin Configuration Of A Seven Segment Display & IC 4511

Once 7-Segment LED displays became readily available, a simple IC known as a "BCD to 7-Segment decoder" was quickly developed to simplify their use... Binary formatted data presented to this IC's inputs results in the IC's outputs being placed into the correct state to display the equivalent numeral (0 to 9) on a 7-Segment display...

Although BCD to 7-Segment decoder ICs are available without built in latches, this particular IC includes a built in 4-bit latch which we will make use of in later examples... For now the latch is set to simply allow input data to freely pass through to the decoder...

In the above diagram, the 4 toggle switches, SW0 to SW3 are used to select the desired numeral (0-9) that will appear on the 7-Segment display... By using a decoder, it's simply a matter of setting the correct 4-bit BCD pattern feeding the inputs of the decoder, and the decoder takes care of the rest...

BCD Input Data
 SW3  SW2   SW1  SW0   Numeral Displayed 
The decoder section also has two additional inputs... Lamp Test (LT) turns all segments on so you can verify at once that all display segments are working.
The Blanking (BL) input is just the reverse; it forces the entire display off... This is used in many cases to blank out leading or trailing zeros from a long display... LT will override BL so you can test even blanked-out display digits.

Interfacing SSD(Seven Segment Display) With A Microcontroller (General):

SSD, Connection With A MCU Port
SSD, Connection With A MCU Port
Use The Below Data, to Write in Your MCU Port & Directly Generate The Required Hex Value on SSD

Hexadecimal encodings for displaying the digits 0 to F
Digit gfedcba abcdefg a b c d e f g
0 0×3F 0×7E on on on on on on off
1 0×06 0×30 off on on off off off off
2 0×5B 0×6D on on off on on off on
3 0×4F 0×79 on on on on off off on
4 0×66 0×33 off on on off off on on
5 0×6D 0×5B on off on on off on on
6 0×7D 0×5F on off on on on on on
7 0×07 0×70 on on on off off off off
8 0×7F 0×7F on on on on on on on
9 0×6F 0×7B on on on on off on on
A 0×77 0×77 on on on off on on on
b 0×7C 0×1F off off on on on on on
C 0×39 0×4E on off off on on on off
d 0×5E 0×3D off on on on on off on
E 0×79 0×4F on off off on on on on
F 0×71 0×47 on off off off on on on

How Do 3.5mm Jacks (TRS Connectors) Works?

3.5mm jack, TRS or TRRS Connectors
3.5mm jack, TRS or TRRS Connectors

  1. 1. Sleeve: usually ground
  2. 2. Ring: Right-hand channel for stereo signals, negative polarity for balanced mono signals, power supply for power-using mono signal sources
  3. 3. Tip: Left-hand channel for stereo signals, positive polarity for balanced mono signals, signal line for unbalanced mono signals
  4. 4. Insulating rings

It is also termed an audio jack, phone jack, phone plug, and jack plug. Specific models are termed stereo plug, mini-stereo, headphone jack, microphone jack, tiny telephone connector, bantam plug.
3.5 mm jacks earphone that we use to listen the music is known technically as TRS connector.
Three-contact versions are known as TRS connectors, where T stands for "tip", R stands for "ring" and S stands for "sleeve". Similarly, two- and four-contact versions are called TS and TRRS connectors respectively.

Audio TRS Mini Plug, or 3.5 mm jack

3.5mm jacks connection, an insider look!
3.5mm jacks connection, an insider look!
In general, in audio applications, the convention is:
  • Sleeve - ground connection
  • Tip - left channel (for stereo audio signals)
  • Ring - right channel (for stereo audio signals)
  • Ring #2 - other (such as microphone audio or power)
In many computer and modern multimedia device applications, sometimes the sleeve (or the tip) is used to pass power to microphones.

The voltage applied to Tip & Ring drives you earphones, and you listen the music. More the voltage applied to them, more the volume you going to hear at the channel you have preferred(mono or stereo).
Note: Device manufacturers can be inconsistent with how they wire jacks intended for their particular device. Sometimes this is driven by a desire to control the market for accessories to be used with  a particular mobile phone

Some other configuration that you will find are:

How Do 3.5mm Jacks (TRS Connectors) Works?
Courtesy Quora

How Does Music Shuffle Works in a Media Player!

Ipod Shuffle. But How Shuffling Works??
Ipod Shuffle. But How Shuffling Works??

Shuffle works just like how you shuffle cards game works! When you hit the play button, it simply randomizes your playlist and plays it until the end, after which it does it again.

Now the technical stuff behind all this is, WMP, Media Monkey, or even the hardware iPod shuffle calls some "random()" function to get a random number from 0 to <1. Then it multiplies it by the number of music files that you have and rounds the result down. This random() & equivalent randomise() function are available in many programming languages such as, JAVA, C++ etc etc.

For example, if you have 150 songs, the first song would have an index of 0 and the 150th song would be having an index of 149. [ Since in computer system every thing starts with zero ].

Say that the random number generated by that random() function, while pressing the next song button is 0.473737. If you multiply that by 150 and round it down, you'll get 71.06055, the index of the 71st song, after rounding off 71.06055 to 71. It then does it again, somehow making sure that the song doesn't get chosen again, until it has completed the playing of of 150 songs.

Functions… the basic necessity of software….

As functions are building block for any software, one should have a good knowledge of atleast some basic functions, so that one can use these functions effectively and in a precise manner.

So what to wait for, let’s start with the basic function “clc”.
“clc” function: -

Clear Command Window

Alternatives: -

As an alternative to the clc function, you can also clear the command window by selecting Edit > Clear Command Window in the MATLAB desktop.

Syntax: -


Description: -

clc function clears all inputs and outputs from the Command Window display, giving you a "clean screen” for the fresh use.
After using clc, you cannot use the scroll bar to see the history of functions, but you still can use the up arrow to recall statements from the command history.

Examples: -

1) Use clc in a MATLAB code file to always display output in the same starting position on the screen.

2) Use clc to clear the command window when you are unable to keep track of the functions you used previously or you want a clear screen to work with.

P.S: - Matlab is case sensitive software so take extra care in using the functions.

Hope to see you in next tutorial…!!!

Written By,

Student  Dheeraj Mor, VIT University

First program…the start to MATLAB atmosphere…

Matlab as a calculator
Have you ever wondered how the scientist makes the precise calculations up to 20 decimal points or how difficult calculations of the eigen value of the matrix of higher orders, etc., etc.
Here I present you the first and very basic use of the Matlab, which 3 in every 5 students are fear off, i.e. calculations. The basic calculations involves addition, subtraction, multiplication, division, square root, etc.
I assumed that now you have good knowledge of different kind of Matlab windows, i.e. how to differentiate different windows.
When you first start Matlab, you will find “>>” symbol in the command window which means you can write whatever you want to write but remember since this software is Matrix based so all the program should be liable and applicable for Matrix.
These are command for some of the basic operations
1)   >> 20+30 ‘Press enter’

ans  =

     2)   >> 30-20 ‘Press enter’

           ans   =

     3)   >> 10*5 ‘Press enter’

ans   =
     4)   >> 10/5 ‘Press enter’

           ans   =

      5)   >> 10\5 ‘Press enter’

           ans   =

Name of operation
Forward division
Backward division

Table: - Symbols and their meaning

P.S:- I would like to advise you that try the above function by your own as well as it help you to learn faster.

Hope to see you in next tutorial…!!!!

Written By,

Student Dheeraj Mor VIT University

Arduino Sketch/Program Build Process-the whole compilation process


A number of things have to happen for our Arduino code to get onto the Arduino board. (Version 1.0.x onwards). First step is that, the Arduino IDE performs some pre-processing tasks to turn our sketch into a C++ program. It then gets passed to a compiler (that is avr-gcc), which turns the High Level Code(Human Understandable) code into machine Language (or object files). Then, your code gets combined with (linking process), the standard Arduino libraries that provide basic functions like digitalWrite() or Serial.print(). The result is a single Intel hex file, which need to be written to the program memory of the chip on the Arduino board. This file is then uploaded to the board: transmitted over the USB or serial connection via the bootloader already on the chip or with external programming hardware.


The Arduino IDE performs a few transformations to your main sketch file (the concatenation of all the tabs in the sketch without extensions) before passing it to the avr-gcc compiler.
When our sketch is compiled, all tabs with no extension are concatenated together to form the "main sketch file" (C++). Then,  "Arduino.h" is added to our sketch. This header file includes all the definitions needed for the standard Arduino core. Next, the IDE searches for function definitions within your main sketch file and creates declarations (prototypes) for them.

No pre-processing is done to .c, .cpp, or .h files in a sketch. Additionally, .h files in the sketch/Arduino Program are not automatically #included from the main sketch file. Further, if you want to call functions defined in a .c file from a .cpp file (like one generated from your sketch), you'll need to wrap its declarations in an 'extern "C" {}' block that is defined only inside of C++ files.


Sketches are compiled by avr-gcc and avr-g++ according to the variables in the boards.txt file of the selected board's platform.
The include path includes the sketch's directory, the board's variant folder (a sub-directory of hardware/arduino/variants specified in boards.txt), the core folder (e.g. the hardware/arduino/core/arduino/ sub-folder of the Arduino application) and the avr include directory (hardware/tools/avr/avr/include/), as well as any library directories (in hardware/libraries/ and the libraries/ sub-directory of your sketchbook) which contain a header file which is included by the main sketch file.
Note that libraries referenced only by another library (and not the main sketch file) are not placed in the include path or linked against the sketch. All libraries used (even indirectly by another library) must be #included by the main sketch file. Also, libraries can't have arbitrary sub-folders. Instead, a special sub-folder "utility", is searched for .c and .cpp files to link in; the "utility" folder is also added to the included path when compiling the library containing it - but not when compiling other files (e.g. headers in the "utility" folder won't be found if #included from the sketch).
When you verify or upload a sketch, it is built in a temporary directory in the system-wide temporary directory (e.g. /tmp on Linux).
The .c and .cpp files of the target are compiled and output with .o extensions(object files) to this directory, as is the main sketch file and any other .c or .cpp files in the sketch and any .c or .cpp files in any libraries which are #included in the sketch.
Before compiling each .c or .cpp file, an attempt is made to reuse the previously compiled .o file, which speeds up the build process. A special .d (dependency) file provides a list of all other files included by the source. The compile step is skipped if the .o and .d files exist and have timestamps newer than the source and all the dependent files. If the source or any dependent file has been modified, or any error occurs verifying the files, the compiler is run normally, writing a new .o & .d file. After a new board is selected from the Tools menu, all .c and .cpp files are rebuilt on the next compile.
These .o files are then linked together into a static library and the main sketch file is linked against this library. Only the parts of the library needed for your sketch are included in the final .hex file, reducing the size of most sketches.
The .hex file is the final output of the compilation which is then uploaded to the board.
If verbose output during compilation is checked in the Preferences dialog, the complete command line of each external command executed as part of the build process will be printed in the editor console.


Sketches are uploaded by avrdude. The upload process is also controlled by variables in the boards and main preferences files.

Floating point values, operations, and typecasting in Arduino


Datatype for floating-point numbers, a number that has a decimal point. Floating-point numbers are often used to approximate analog and continuous values because they have greater resolution than integers. Floating-point numbers can be as large as 3.4028235E+38 and as low as -3.4028235E+38. They are stored as 32 bits (4 bytes) of information.
Floats have only 6-7 decimal digits of precision. That means the total number of digits, not the number to the right of the decimal point. Unlike other platforms, where you can get more precision by using a double (e.g. up to 15 digits), on the Arduino, double is the same size as float.
Floating point numbers are not exact, and may yield strange results when compared. For example 6.0 / 3.0 may not equal 2.0. You should instead check that the absolute value of the difference between the numbers is less than some small number.
Floating point math is also much slower than integer math in performing calculations, so should be avoided if, for example, a loop has to run at top speed for a critical timing function. Programmers often go to some lengths to convert floating point calculations to integer math to increase speed.



    float myfloat;
    float sensorCalbrate = 1.117;



    float var = val;
  • var - your float variable name
  • val - the value you assign to that variable


Example Code

   int x;
   int y;
   float z;

   x = 1;
   y = x / 2;            // y now contains 0, ints can't hold fractions
   z = (float)x / 2.0;   // z now contains .5 (you have to use 2.0, not 2)
//type casting