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Arduino

Arduino is an open source hardware and software platform, which can be used for building electronics projects. It consists of an electronics board and a software to work with that board. It also comes with an IDE (integrated development environment) which runs on your PC.

What all things Arduino can do?

Arduino can interact with buttons, LEDs, sensors, motors and several other electronic devices. You will need separate connector and cables though. To state some sample projects – 3D Printer, Robots, Drones, Home Automation etc.

Arduino Uno - R3

Arduino is a brand name, however, their hardware and software are available under open-source. Even the circuit diagrams are available, in case someone wants to create the board themselves! As a result, there are other clones also available for Arduino hardware.

Each board can work independently after loading the program initially. Or it can work in tandem with other Arduino boards to provide additional functionality. Or it can also remain connected with a computer to carry out tasks which need access to data from sensors. A board contains following components:

  • USB connector – power as well as connectivity with computer
  • Various pins such a Ground, 3.3V, 5V, analog and digital
  • RESET button
  • Power Indicator
  • Transmitter and Receiver
  • Main IC (Integrated Circuit)

Arduino family contains multiple boards:

  • Uno
  • LilyPad
  • RedBoard
  • Leonardo

Some of the projects that you can build using this board:

  • Smart blind stick – one can use sensor to detect the obstacles and give feedback using a buzzer
  • Metal Detector
  • Measure Sound Level
  • Club it with Thermistor and you can control temperature in your room

You can find a huge list on the internet for such projects and also quite a few videos on youtube.

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Related Keywords

Hardware, Electronics, DIY

 

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Progressive Image

Large images on landing pages is a nightmare for any web developer. She has to optimize the page load time without affecting the user experience or the quality of the images on the page. If the landing page loads slow, it usually drives away the visitors. This is where the progressive image might be helpful.

What is Progressive Image?

Progressive Image is actually a JPEG format image, which is created using algorithms that load the image in successive waves. When an image is loaded into the browser, it starts rendering the image immediately. A standard JPEG image, also known as Baseline Image, is rendered from top to bottom and appears to be loading in tranches. Whereas when a progressive image is rendered, an entire image block is rendered in one go, albeit at a reduced quality. As the remaining image is loaded, the quality of the image improves. With baseline image, the user may get a feeling of slow loading time, whereas in the second case, the user starts seeing the image almost instantly and hence there’s perceived improvement in user experience.

Almost all the image processing software allows users to create a progressive image, should the user chooses to. Thing to note is that the size of the image increases marginally.

Any examples?

Take a look at this example given in “TourWriter” Blog

Baseline JPG loading
Baseline JPG loading
Progressive Image Loading
Progressive Image Loading

You can also watch a nice video on this here.

Then why not everyone using Progressive Image?

As can be expected, there have been several studies around the usefulness of progressive images for improving the user experience. And there are opposite opinions. I came across one such study by Radware Blog. This team carried ou an experiment with 700+ participants. By observing the facial expressions while watching different types of images, page load times etc, they have come to a conclusion that Progressive Image doesn’t improve the user experience to a large extent.

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Related Keywords

Web Development, User Experience

 

 

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ESB

Ever wondered how heterogeneous applications communicate with each other? e.g. A Java application that needs to communicate with a .Net application. And not just one-to-one communication. Consider use cases where there are several applications talking to more than one applications. How does it happen? Does each application need to implement an interface for every other application? Enterprise Service Bus i.e. ESB comes to your rescue.

What is Enterprise Service Bus?

ESB implements a communication system between various applications which need to communicate with each other. The primary goal of ESB is to enable faster integration between Enterprise applications commonly referred as EAI.

ESB
Consider a set of applications which need to communicate with each other. This is a heterogeneous set and each one talks separate standard, protocol. And many of them need to talk to more than one applications. ESB removes the need that each application needs to implement communication with more than one other applications. If one tries to implement point-to-point communication between apps, it is going to get messy. Changing one part would result in breaking something else. ESB handles the communication transparently and hence eases up the process of communication.

Key capabilities of ESB

  • Transport protocol conversion – JMS to file
  • Message transformation
  • Routing e.g. content based routing
  • Message enhancement e.g. Order data that only has a client ID can be enhanced to pass Order Data and client details together to next level. In this case, client details are pulled from a different source and the incoming message is “enhanced” with additional client data before passing it to next application.
  • Security / Authorization – incoming messages are checked for required authorization before processing them further.
  • Mediation
  • Monitoring

Key providers of Enterprise Service Bus software

  • Microsoft BizTalk Server
  • MuleSoft
  • Oracle Enterprise Service Bus
  • Tibco Software
  • Apache ServiceMix

Related Links

Related Keywords

Software Architecture, Service Oriented Architecture

 

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TypeScript

TypeScript is an opensource programming language, which is a superset of Javascript. This language was originally developed at Microsoft and was later made opensource in Oct 2012.

TypeScript
TypeScript programmer

What is so special about TypeScript?

JavaScript was originally developed to handle simple applications. As applications started growing, the code became complex. Additionally, JavaScript wasn’t offering several concepts from standard object-oriented programming e.g. easy class definitions. It also didn’t offer type check and type of the variable was inferred at runtime.

TypeScript resolves problems like this. TypeScript scripts are compiled and converted into JS files. All the existing JS files are completely valid in TypeScript (in fact you can rename a JS file as TS file and can use it!!). However, the reverse is not true.

Key advantages of using TypeScript language:

  • Static Type (Optional): Developer can define a type of the variables and it will be checked during compile time. This helps in reducing the errors at runtime. Supported types are explained briefly in the section below.
  • OO support: Developer can define the classes and have OO implemented using TypeScript. They can use static functions, variable scopes, function overloading, interfaces and inheritance
  • JS compatibility: Existing Javascript files could be used as TypeScript files without any problem.
  • Modules: Allows to define your own modules as well as allows to combine external modules easily.

Supported variable types:

  • Any – default type – all JS variables get initially mapped to this type until their type could be inferred at runtime.
  • boolean
  • number (integer, long, short…)
  • string (string, char)
  • type[] (Arrays)

IDE support for TypeScript

  • MS Visual Studio
  • IntelliJ IDEA
  • Eclipse Plugin

TypeScript compiler compiles the “.ts” scripts to generate javascript code. During this compilation, the compiler checks for various errors, thereby reducing the problems getting detected at runtime.

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Related Keywords

AngularJS, Angular, Javascript, CoffeeScript, ECMAScript, Grunt, Node.js

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ADC – Application Delivery Controller

Application Delivery Controller aka ADC is an advanced version of server load balancing (SLB) which includes traditional load balancing along with some advance features such as health checks, SSL offloading, DDoS protection, Reverse Proxy, WAF etc.

Application Delivery Controller
Network Panel

History of Application Delivery Controller

Load balancing among several servers is not new. An initial version of load balancing was to have 1 to many relations between the domain name and IP addresses in DNS server. This severely lacked health checks as clients wouldn’t know if given IP is working or not. This drawback gave rise to next level of load balancing where a specific IP address was exposed to the world. This IP was catered by clustering software, which routed the traffic from clients to several servers in the backend.

Next generation load balancers introduced health monitors. If any of the servers goes unresponsive, the load balancer would stop sending traffic to that server until it was recovered. This also allowed system administrators to build some custom logic to add or reduce the servers in the farm based on the monitoring data.

ADCs are current generation load balancers which provide a variety of functions bundled together. Some of them are listed in the section below.

Features of ADC

Application Delivery Controller
Application Delivery Controller – ADC. Source: https://aiscaler.com/application-delivery-controllers-on-the-cloud
  • SSL Offloading: ADC can handle the terminating SSL connection keeping the traffic between ADC and backend servers in plain text. And hence it helps in reducing the load on the application servers in the server farm.
  • Multilayer load balancing: These load balancers can balance traffic at Layer 3/4 as well as Layer 7 of OSI model. Thus it gives an ability to route traffic based on IP addresses, subnets as well as based on the URL patterns, domains and HTTP header fields.
  • Load balancing methods: ADCs can use various methods such as round robin, least packets, least bandwidth, latency or hashing of certain parameters.
  • DDoS Protection: ADCs can look into the incoming traffic and detect DDoS before it starts loading the application servers, thereby defeating the attack.
  • WAF: ADCs can have built-in Web Application Firewall which can prevent common security attacks such as Cross-site scripting XSS.

For a much more comprehensive list, you can to the article in related links section.

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Related Keywords

Load Balancer, Hardware, WAF, DAF