In this article by Don Wilcher author of the book Arduino Electronics Blueprints , we will see how a programmable logic controller ( PLC ) is used to operate various electronic and electromechanical devices that are wired to I/O wiring modules. The PLC receives signals from sensors, transducers, and electromechanical switches that are wired to its input wiring module and processes the electrical data by using a microcontroller. The embedded software that is stored in the microcontroller's memory can control external devices, such as electromechanical relays, motors (the AC and DC types), solenoids, and visual displays that are wired to its output wiring module. The PLC programmer programs the industrial computer by using a special programming language known as ladder logic . The PLC ladder logic is a graphical programming language that uses computer instruction symbols for automation and controls to operate robots, industrial machines, and conveyor systems. The PLC, along with the ladder logic software, is very expensive. However, with its off-the-shelf electronic components, Arduino can be used as an alternate mini industrial controller for Maker type robotics and machine control projects. In this article, we will see how Arduino can operate as a mini PLC that is capable of controlling a small electric DC motor with a simple two-step programming procedure. Details regarding how one can interface a transistor DC motor with a discrete digital logic circuit to an Arduino and write the control cursor selection code will be provided as well. This article will also provide the build instructions for a programmable motor controller. The LCD will provide the programming directions that are needed to operate an electric motor. The parts that are required to build a programmable motor controller are shown in the next section.
In this article by Gavin Henrick and Karen Holland , author of the book Moodle Administration Essentials , roles play a key part in the ability of the Moodle site. They are able to restrict the access of users to only the data they should have access to, and whether or not they are able to alter it or add to it. In each course, every user will have been assigned a role when they are enrolled, such as teacher, student, or customized role. In this article, we deal with the essential areas of role management that every administrator may have to deal with: Cloning a role Creating a new role Creating a course requester role Overriding a permission in a role in a course Testing a role Manually adding a role to a user in a course Enabling self-enrolment for a course
In this article by, Francesco Malatesta author of the book, Learning Laravel’s Eloquent , we will learn everything about Eloquent, starting from the very basics and going through models, relationships, and other topics. You probably started to like it and think about implementing it in your next project. In fact, creating an application without a single SQL query is tempting. Maybe you also showed it to your boss and convinced him/her to use it in your next production project. However, there is a little problem. Yeah, the next project isn't so new. It already exists, and, despite everything, it doesn't use Laravel! You start to shiver. This is so sad because you passed the last week studying this new ORM, a really cool one, and then moving forward. There is always a solution! You are a developer! Also, the solution is not so hard to find. If you want, you can use Eloquent without Laravel. Actually, Laravel is not a monolithic framework. It is made up of several, separate parts, which are combined together to build something greater. However, nothing prevents you from using only selected packages in another application. So, what are we going to see in this article? First of all, we will explore the structure of the database package and see what is inside it. Then, you will learn how to install the illuminate/database package separately for your project and how to configure it for the first use. Then, you will encounter some examples. First of all, we will look at the Eloquent ORM . You will learn how to define models and use them. Having done this, as a little extra, I will show you how to use the Query Builder (remember that the "illuminate/database" package isn't just Eloquent). Maybe you would also enjoy the Schema Builder class. I will cover it, don't worry! We will cover the following: Exploring the directory structure Installing and configuring the database package Using the ORM Using the Query and Schema Builders Summary
In this article by Brenden Sewell , author of the book Blueprints Visual Scripting for Unreal Engine , we will cover the following topics: Exploring materials Creating our first Blueprint When setting out to develop a game, one of the first steps toward exploring your idea is to build a prototype. Fortunately, Unreal Engine 4 and Blueprints make it easier than ever to quickly get the essential gameplay functionality working so that you can start testing your ideas sooner. To develop some familiarity with the Unreal editor and Blueprints, we will begin by prototyping simple gameplay mechanics using some default assets and a couple of Blueprints.
In this article by Mário Kašuba , author of the book Lua Game Development Cookbook , explains that maze pathfinding can be used effectively in many types of games, such as side-scrolling platform games or top-down, gauntlet-like games. The point is to find the shortest viable path from one point on the map to another. This can be used for moving NPCs and players as well.
A geo point refers to the latitude and longitude of a point on Earth. Each location on it has its own unique latitude and longitude. Elasticsearch is aware of geo-based points and allows you to perform various operations on top of it. In many contexts, it's also required to consider a geo location component to obtain various functionalities. For example, say you need to search for all the nearby restaurants that serve Chinese food or I need to find the nearest cab that is free. In some other situation, I need to find to which state a particular geo point location belongs to understand where I am currently standing. This article by Vineeth Mohan , author of the book Elasticsearch Blueprints , is modeled such that all the examples mentioned are related to real-life scenarios, of restaurant searching, for better understanding. Here, we take the example of sorting restaurants based on geographical preferences. A number of cases ranging from the simple, such as finding the nearest restaurant, to the more complex case, such as categorization of restaurants based on distance are covered in this article. What makes Elasticsearch unique and powerful is the fact that you can combine geo operation with any other normal search query to yield results clubbed with both the location data and the query data.
In the article written by Giovanni Maruzzelli, author of FreeSWITCH 1.6 Cookbook , we learn how WebRTC is all about security and encryption. Theye are not an afterthought. They're intimately interwoven at the design level and are mandatory. For example, you cannot stream audio or video clearly (without encryption) via WebRTC.
In this article by Malcolm Sherrington , author of the book Mastering Julia , we will see why write a book on Julia when the language is not yet reached the version v1.0 stage? It was the first question which needed to be addressed when deciding on the contents and philosophy behind the book.
In this article, Luigi Fugaro , author of the book Wildfly Cookbook says that the JBoss.org community is a huge community, where people all over the world develop, test, and document pieces of code. There are a lot of projects in there, not just JBoss AS, which is now WildFly. I can mention a few: Infinispan, Undertow, PicketLink, Arquillian, HornetQ, RESTeasy, AeroGear, and Vert.X. For a complete list of all projects, visit http://www.jboss.org/projects/.
In this article by, Stephen Haney , author of the book Game Development with Swift , we will focus on building great gameplay experiences while SpriteKit performs the mechanical work of the game loop . To draw an item to the screen, we create a new instance of a SpriteKit node. These nodes are simple; we attach a child node to our scene, or to existing nodes, for each item we want to draw. Sprites, particle emitters, and text labels are all considered nodes in SpriteKit. The topics in this article include: Drawing your first sprite Animation: movement, scaling, and rotation Working with textures Organizing art into texture atlases For this article, you need to first install Xcode, and then create a project. The project automatically creates the GameScene.swift file as the default file to store the scene of your new game.
In this article by Sandro Pasquali , author of Deploying Node.js , we will learn about the following: Automating the deployment of applications, including a look at the differences between continuous integration, delivery, and deployment Using Git to track local changes and triggering deployment actions via webhooks when appropriate Using Vagrant to synchronize your local development environment with a deployed production server Provisioning a server with Ansible Note that application deployment is a complex topic with many dimensions that are often considered within unique sets of needs. This article is intended as an introduction to some of the technologies and themes you will encounter. Also, note that the scaling issues are part and parcel of deployment.