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Develop innovative hardware-based projects in C The Raspberry Pi has traditionally been programmed using Python. Although this is a very powerful language, many programmers may not be familiar with it. C on the other hand is perhaps the most commonly used programming language and all embedded microcontrollers can be programmed using it. The C language is taught in most technical colleges and universities and almost all engineering students are familiar with using it with their projects. This book is about using the Raspberry Pi with C to develop a range of hardware-based projects. Two of the most popular C libraries, wiringPi and pigpio are used. The book starts with an introduction to C and most students and newcomers will find this chapter invaluable. Many projects are provided in the book, including using Wi-Fi and Bluetooth to establish communication with smartphones. Many sensor and hardware-based projects are included. Both wiringPi and pigpio libraries are used in all projects. Complete program listings are given with full explanations. All projects have been fully tested and work. The following hardware-based projects are provided in the book: Using sensors Using LCDs I²C and SPI buses Serial communication Multitasking External and timer interrupts Using Wi-Fi Webservers Communicating with smartphones Using Bluetooth Sending data to the cloud Program listings of all Raspberry Pi projects developed in this book are available on the Elektor website. Readers can download and use these programs in their projects. Alternatively, they can customize them to suit their applications.

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RFID technology has conquered many areas in which barcodes, magnetic strips and contact smartcards were used previously. Everyday applications, such as electronic ticketing, access cards, debit cards and electronic identity documents would not be possible without this technology. MIFARE is the most widely used RFID technology, and this book provides a practical and comprehensive introduction to it. Among other things, the initial chapters cover physical fundamentals, relevant standards, RFID antenna design, security considerations and cryptography. The complete design of a reader’s hardware and software is described in detail. The reader’s firmware and the associated PC software support programming using any .NET language. The specially developed PC program, “Smart Card Magic.NET”, is a simple development environment that supports sending commands to a card at the click of a mouse, as well as the ability to create C# scripts. Alternatively, one may follow all of the examples using Visual Studio 2010 Express Edition. Finally, the major smart card reader API standards are introduced. The focus is on programming contactless smartcards using standard PC/SC readers using C/C++, Java and C#.

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Using the RFID Starter Kit An Arduino board has now become ‘the’ basic component in the maker community. No longer is an introduction to the world of microcontrollers the preserve of the expert. When it comes to expanding the capabilities of the basic Arduino board however, the developer is still largely on his own. If you really want to build some innovative projects it’s often necessary to get down to component level. This can present many beginners with major problems. That is exactly where this book begins. This book explains how a wide variety of practical projects can be built using items supplied in a single kit together with the Arduino board. This kit, called the 'RFID Starter Kit for Arduino' (SKU 17240) is not just limited to RFID applications but contains more than 30 components, devices and modules covering all areas of modern electronics. In addition to more simple components such as LEDs and resistors there are also complex and sophisticated modules that employ the latest technology such as: A humidity sensor A multicolor LED A large LED matrix with 64 points of light A 4-character 7-segment LED display An infra red remote-controller unit A complete LC-display module A servo A stepper motor and controller module A complete RFID reader module and security tag On top of that you will get to build precise digital thermometers, hygrometers, exposure meters and various alarm systems. There are also practical devices and applications such as a fully automatic rain sensor, a sound-controlled remote control system, a multifunctional weather station and so much more. All of the projects described can be built using the components supplied in the Elektor kit.

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The Arduino Uno is an open-source microcontroller development system encompassing hardware, an Integrated Development Environment (IDE), and a vast number of libraries. It is supported by an enormous community of programmers, electronic engineers, enthusiasts, and academics. The libraries in particular really smooth Arduino programming and reduce programming time. What’s more, the libraries greatly facilitate testing your programs since most come fully tested and working. The Raspberry Pi 4 can be used in many applications such as audio and video media devices. It also works in industrial controllers, robotics, games, and in many domestic and commercial applications. The Raspberry Pi 4 also offers Wi-Fi and Bluetooth capability which makes it great for remote and Internet-based control and monitoring applications. This book is about using both the Raspberry Pi 4 and the Arduino Uno in PID-based automatic control applications. The book starts with basic theory of the control systems and feedback control. Working and tested projects are given for controlling real-life systems using PID controllers. The open-loop step time response, tuning the PID parameters, and the closed-loop time response of the developed systems are discussed together with the block diagrams, circuit diagrams, PID controller algorithms, and the full program listings for both the Raspberry Pi and the Arduino Uno. The projects given in the book aim to teach the theory and applications of PID controllers and can be modified easily as desired for other applications. The projects given for the Raspberry Pi 4 should work with all other models of Raspberry Pi family. The book covers the following topics: Open-loop and closed-loop control systems Analog and digital sensors Transfer functions and continuous-time systems First-order and second-order system time responses Discrete-time digital systems Continuous-time PID controllers Discrete-time PID controllers ON-OFF temperature control with Raspberry Pi and Arduino Uno PID-based temperature control with Raspberry Pi and Arduino Uno PID-based DC motor control with Raspberry Pi and Arduino Uno PID-based water level control with Raspberry Pi and Arduino Uno PID-based LED-LDR brightness control with Raspberry Pi and Arduino Uno

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Einfache und kostengünstige digitale Signalverarbeitung Ziel dieses Buches ist es, die Grundprinzipien der digitalen Signalverarbeitung (DSP) zu vermitteln und sie unter Verwendung eines Minimums an Mathematik aus praktischer Sicht einzuführen. Es wird nur das Grundniveau der Theorie zeitdiskreter Systeme vermittelt, das ausreicht, um DSP-Anwendungen in Echtzeit zu implementieren. Die praktischen Umsetzungen werden in Echtzeit mithilfe des beliebten Mikrocontroller-Entwicklungsboards ESP32 DevKitC beschrieben. Mit dem kostengünstigen und äußerst beliebten ESP32-Mikrocontroller sollten Sie in der Lage sein, grundlegende DSP-Projekte mit Abtastfrequenzen im Audiobereich zu entwerfen. Die gesamte Programmierung erfolgt mit der beliebten Arduino IDE in Verbindung mit dem C-Sprachcompiler. Nachdem das Buch eine solide Grundlage der DSP-Theorie und relevante Diskussionen über die wichtigsten DSP-Softwaretools auf dem Markt gelegt hat, werden die folgenden audiobasierten Sound- und DSP-Projekte vorgestellt: Verwendung eines I²S-basierten digitalen Mikrofons zur Audioaufnahme Verwendung eines I²S-basierten Klasse-D-Audioverstärkers und Lautsprechers Wiedergabe von auf einer SD-Karte gespeicherter MP3-Musik über einen I²S-basierten Verstärker und Lautsprecher Wiedergabe von im ESP32-Flash-Speicher gespeicherten MP3-Musikdateien über einen I²S-basierten Verstärker und Lautsprecher Mono- und Stereo-Internetradio mit I²S-basierten Verstärkern und Lautsprechern Text-zu-Sprache-Ausgabe mit einem I²S-basierten Verstärker und Lautsprecher Verwendung der Lautstärkeregelung in I²S-basierten Verstärker- und Lautsprechersystemen Ein sprechender Veranstaltungszähler mit einem I²S-basierten Verstärker und Lautsprecher Ein einstellbarer Sinusgenerator mit I²S-basiertem Verstärker und Lautsprecher Verwendung des schnellen 24-Bit-ADC/DAC-Moduls Pmod I²S2 Digitales Tiefpass- und Bandpass-Echtzeit-FIR-Filterdesign mit externer und interner A/D- und D/A-Wandlung Digitales Tiefpass- und Bandpass-Echtzeit-IIR-Filterdesign mit externer und interner A/D- und D/A-Wandlung Schnelle Fourier-Transformationen (FFT)

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A Hands-on Guide to Crafting Your Own Power Plant The book you are about to read provides a step-by-step guide for building a renewable energy power plant at home. Our goal was to make the book as practical as possible. The material is intended for immediate application with a small amount of theory. Yet, the theory is important as a foundation that saves time and effort by disabusing the readers of potential misconceptions. Specifically, upon having a firm understanding of photovoltaic physics, you will not be inclined to fruitlessly search for 90% efficient solar panels! We want our readers to be the “doers”. If the book gets covered in grime and some pages become torn while you are building your power plant – this is the best compliment to us. The book covers solar and wind energy. Also, a curious power source based on manure is discussed as well, giving the doers an opportunity to further develop the manure fuel cell. It is important to note that there are many companies offering installation of complete solar solutions. Upon installing the panels, the system is not owned by the customer. Therefore, there is no freedom for experimentation and optimization. Also, none can beat the cost of a DIY solution as well as the ultimate satisfaction. All that is written here is a result of us building a renewable energy solution in Southern California. As the book was completed, the energy began flowing!

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Das Buch ist im Wesentlichen zweigeteilt: Im ersten Teil werden Techniken vorgestellt, mit denen parallele Programmabläufe realisiert werden können. Diese reichen von der einfachen automatischen Ablaufsteuerung eines Hintergrundprozesses durch Interrupts bis zur Implementierung eines an die beschränkten Möglichkeiten von AVR-Mikrocontrollern angepassten RTOS. Die Realisierung von Hintergrundprozessen lässt sich auf bequeme Weise mit Interrupts durchführen. Auf die Probleme der Synchronisierung mit Hintergrundprozessen wird ausführlich eingegangen. Interrupts werden zwar auch in ihrer „natürlichen“ Umgebung vorgestellt, aber es werden auch „exotische“ Einsätze von Interrupts beschrieben, z. B. der Einsatz eines Timer-Interrupts als Programmschleifenzähler. Dass sinnvolles Multitasking auch für die kleineren Mikrocontroller der AVR-Serie möglich ist, wird mit Kleinsystemen demonstriert, die auch auf einem ATtiny2313 ablaufen können. Für Controller mit besserer Ausstattung ist das System SLIMOS gedacht – in dem Prozesse dynamische Objekte sind – in dem Prozesse mit Semaphoren und Ereignissen synchronisiert werden können – welches Interrupts als Ereignisse integriert und eine Zeitablaufsteuerung für inaktive Prozesse besitzt.Der zweite Teil des Buches ist der Numerik gewidmet. Höhepunkt ist die Implementierung einer AVR-freundlichen Fließkommaarithmetik, die dennoch den Standard IEEE 754 soweit umsetzt, wie das bei den kleinen AVR-Prozessoren sinnvoll erscheint. Der Vorstellung und Erläuterung dieses Standards ist ein eigenes Kapitel gewidmet. Zusätzlich gibt es noch ein vorbereitendes Kapitel, in dem die Grundbegriffe der Fließkommaarithmetik erklärt werden, das aber auch esoterische Aspekte erläutert, wie etwa das vom Standard geforderte Rechnen mit Unendlichkeiten. Ein weiteres Kapitel beschreibt die Erzeugung von Zufallszahlen. Es wird gezeigt, wie Zufallszahlen mit diskreter Verteilung, Gleichverteilung, Exponentialverteilung und Normalverteilung berechnet werden können. Sie werden als sehr schnelle Versionen in Fixkommaarithmetik bereit gestellt, woraus dann Fließkommaversionen entwickelt werden. Ein Beispiel für ihren Einsatz ist im Simulationsabschnitt des SLIMOS-Kapitels zu finden.Der Anhang bietet u. a. eine sehr AVR-freundliche Realisierung der Methode von Fletcher und die Implementierung von Funktoren, die elegante Problemlösungen gestatten.Alle Programme sind so ausführlich erläutert und kommentiert, dass der Leser keine Schwierigkeiten damit haben dürfte, sie an eigene Bedürfnisse anzupassen. Der für alle Programme verwendete Assembler wird vom Hersteller der AVR-Mikrocontroller kostenlos zur Verfügung gestellt.Band 2 ist als gedrucktes Buch erhältlich: Systemprogrammierung II für AVR-Mikrocontroller

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Clever Tricks with ATmega328 Pro Mini Boards With a simple Pro Mini board and a few other components, projects that 20 or 30 years ago were unthinkable (or would have cost a small fortune) are realized easily and affordably in this book: From simple LED effects to a full battery charging and testing station that will put a rechargeable through its paces, there’s something for everyone. All the projects are based on the ATmega328 microcontroller, which offers endless measuring, switching, and control options with its 20 input and output lines. For example, with a 7-segment display and a few resistors, you can build a voltmeter or an NTC-based thermometer. The Arduino platform offers the perfect development environment for programming this range of boards. Besides these very practical projects, the book also provides the necessary knowledge for you to create projects based on your own ideas. How to measure, and what? Which transistor is suitable for switching a certain load? When is it better to use an IC? How do you switch mains voltage? Even LilyPad-based battery-operated projects are discussed in detail, as well as many different motors, from simple DC motors to stepper motors. Sensors are another exciting topic: For example, a simple infrared receiver that can give disused remote controls a new lease on life controlling your home, and a tiny component that can actually measure the difference in air pressure between floor and table height!

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A Small Basic Approach There are many different PC programming languages available on the market. Some have beautiful names; some have easy to use development tools. Others have incredible power. They all have one thing in common: they assume that you have, or want to have, a knack for technology and difficult to read commands. In this book we take a practical approach to programming. We assume that you simply want to write a PC program, and write it quickly. Not in a professional environment, not in order to start a new career, but for plain and simple fun... or just to get a task done. Therefore we use Small Basic. You will have an application up and running in a matter of minutes. You will understand exactly how it works and be able to write text programs, graphical user interfaces, and advanced drivers. It is so simple; you don't even need to be an adult!

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Praktische Einführung in 3D-Modellierung vom Gehäuse bis zu Frontplatten Ein historisches Bauteil einbetten, eine professionell anmutende Heimstätte für eine Leiterplatte schaffen oder ein komplexes Gerät mit Chassis konstruieren – diese und viele andere Herausforderungen werden mit FreeCAD zu einem anregenden Vergnügen. Hat man die grundlegenden Prozesse erst einmal verinnerlicht, sind der Fantasie praktisch keine Grenzen mehr gesetzt. Der Einstieg in ein neues Programm ist immer schwierig – besonders wenn es sich um ein so vielfältiges Werkzeug wie FreeCAD handelt. Überschaubare, aber zugleich gut verwendbare Einzelteile liefern in diesem Buch den Anfangspunkt. Das Zusammensetzen dieser Komponenten führt später zu Baugruppen. In der Vielfalt der Möglichkeiten von FreeCAD wird ein gangbarer Weg gezeigt. Das beschriebene Vorgehen ist exemplarisch – die Beispiele lassen sich daher leicht auf eigene Aufgaben anwenden. Die Geräte wurden vom Autor angefertigt und mit Fotos illustriert. Eine 3D-Konstruktion erfordert etwas Aufwand, der sich aber lohnt: Neben einer beeindruckenden Darstellung von Projekten wird zugleich die Möglichkeit geliefert, z. B. Blechteile zur Fertigung abzuwickeln und für die Werkstatt aussagekräftige Zeichnungen zu exportieren. Schon bald werden Sie auf FreeCAD nicht mehr verzichten wollen!

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Practical Introduction to 3D Modeling from Enclosure to Front Panel Embedding a vintage component, creating a professional looking home for a circuit board, or even designing a complex apparatus complete with a chassis – these and many other challenges turn into a stimulating pleasure with FreeCAD. Once you have internalized the basic processes, there are virtually no limits to your imagination. Starting to use a new software is never straightforward – especially with a tool as versatile as FreeCAD. Manageable, but at the same time easily usable individual components provide the starting point in this book. Putting these components together later results in assemblies. In the FreeCAD universe, a workable trajectory is demonstrated. The described procedure is illustrative so the examples are easily applied to custom tasks. The devices were made by the author and illustrated with photos. Creating a 3D design is requiring some effort but the initial investment pays off soon. Besides the impressive spatial representation of the projects, the extracted drawings yield a solid base for documentation and production. Extended FreeCAD capabilities like the unfolding of sheet metal parts enormously add to efficiency and pushes models forward into practical assembly. Soon you will definitely not want to do without FreeCAD!

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Ready to explore the world around you? By attaching the Sense HAT to your Raspberry Pi, you can quickly and easily develop a variety of creative applications, useful experiments, and exciting games. The Sense HAT contains several helpful environmental sensors: temperature, humidity, pressure, accelerometer, magnetometer, and gyroscope. Additionally, an 8x8 LED matrix is provided with RGB LEDs, which can be used to display multi-color scrolling or fixed information, such as the sensor data. Use the small onboard joystick for games or applications that require user input. In Innovate with Sense HAT for Raspberry Pi, Dr. Dogan Ibrahim explains how to use the Sense HAT in Raspberry Pi Zero W-based projects. Using simple terms, he details how to incorporate the Sense HAT board in interesting visual and sensor-based projects. You can complete all the projects with other Raspberry Pi models without any modifications. Exploring with Sense HAT for Raspberry Pi includes projects featuring external hardware components in addition to the Sense HAT board. You will learn to connect the Sense HAT board to the Raspberry Pi using jumper wires so that some of the GPIO ports are free to be interfaced to external components, such as to buzzers, relays, LEDs, LCDs, motors, and other sensors. The book includes full program listings and detailed project descriptions. Complete circuit diagrams of the projects using external components are given where necessary. All the projects were developed using the latest version of the Python 3 programming language. You can easily download projects from the book’s web page. Let’s start exploring with Sense HAT.

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