The Secret of Successful TECHNOLOGY

 RFID Security Access Control System using 8051 Microcontroller is an RFID Technology based security system. Using this system, authorization of personnel is carried out with an RFID card and only those with access can enter a secured area. Components REQUIRED COMPONENTS AT89C51 Microcontroller AT89C51 Programming Board 11.0592 MHz Quartz Crystal 2 x 33pF Ceramic Capacitors 2 x 10KΩ Resistor 10µF Electrolytic Capacitor Push Button 16 x 2 LCD Display 3 x 1KΩ Resistor 10KΩ POT EM-18 RFID Reader Module L293D Motor Driver IC Motor Connecting Wires RFID Description Radio Frequency Identification or simply RFID is a wireless technology generally used for automatic identification and data collection. RFID technology is used for accessing data from a uniquely identify RFID card or tag by combining the radio frequency and microchip technologies i.e. the data is retrieved or stored into the RFID cards without making any physical contact. With the help of RFID technology we can create smart s...

Every Electronic device or product requires a reliable power supply unit (PSU)operate it. Almost all devices in our home, like TV, Printer, Music Player,etc. consists of a power supply unit built into it which converts the AC mains voltage to a suitable level of DC voltage for them to operate. The most commonly used type of power supply circuit is the SMPS (Switching Mode Power Supply), you can easily find this type of circuits in your 12V adapter or Mobile/Laptop charger. In this tutorial, we will learn how to build a 12v SMPS circuit that would convert AC mains power to 12V DC with a maximum current rating of 1.25A. This circuit can be used to power small loads or even be adapted into a charger to charge you lead-acid and lithium batteries. If this 12v 15watt power supply circuit doesn’t match your requirement, you can check various power supply circuit with different ratings. Before proceeding with any kind of power supply design, requirement analysis has to be done based on the...

 C++ Variables Variables are containers for storing data values. In C++, there are different types of variables (defined with different keywords), for example: int - stores integers (whole numbers), without decimals, such as 123 or -123 double - stores floating point numbers, with decimals, such as 19.99 or -19.99 char - stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotes string - stores text, such as "Hello World". String values are surrounded by double quotes bool - stores values with two states: true or false Declaring (Creating) Variables To create a variable, specify the type and assign it a value: Syntax type variableName = value; Where type is one of C++ types (such as int), and variableName is the name of the variable (such as x or myName). The equal sign is used to assign values to the variable. To create a variable that should store a number, look at the following example: Example Create a variable called myNum o...

 C++ Comments C++ Comments Comments can be used to explain C++ code, and to make it more readable. It can also be used to prevent execution when testing alternative code. Comments can be singled-lined or multi-lined. Single-line Comments Single-line comments start with two forward slashes (//). Any text between // and the end of the line is ignored by the compiler (will not be executed). This example uses a single-line comment before a line of code: Example // This is a comment cout << "Hello World!"; This example uses a single-line comment at the end of a line of code: Example cout << "Hello World!"; // This is a comment C++ Multi-line Comments Multi-line comments start with /* and ends with */. Any text between /* and */ will be ignored by the compiler: Example /* The code below will print the words Hello World! to the screen, and it is amazing */ cout << "Hello World!"; Single or multi-line comments? It is up to you which you want to u...

 C++ Output (Print Text) The cout object, together with the << operator, is used to output values/print text: for example ; #include <iostream> using namespace std; int main() {   cout << "Hello World!";   return 0; } Note: You can add as many cout objects as you want. However, note that it does not insert a new line at the end of the output: #include <iostream> using namespace std; int main() {   cout << "Hello World!";   cout << "I am learning C++";   return 0; }

C++ Syntax C++ Basic Syntax Object − Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors -... Class − A class can be defined as a template/blueprint that describes the behaviors/states that object of its type. for example ; #include <iostream> int main() {   std::cout << "Hello World!";   return 0; } Example explained Line 1: #include <iostream> is a header file library that lets us work with input and output objects, such as cout (used in line 5). Header files add functionality to C++ programs. Line 2: using namespace std means that we can use names for objects and variables from the standard library. Don't worry if you don't understand how #include <iostream> and using namespace std works. Just think of it as something that (almost) always appears in your program. Line 3: A blank line. C++ ignores white space. But we use it to make the code more readable. Line 4: Another thing that always app...