All you need to know about good acoustics and sound systems in performance and worship spaces!
Everyone knows that the ability to hear music in balance and to understand speech is essential in any space used for performance or worship. Unfortunately, in the early 21st century, we find that buildings with good acoustics are the exception rather than the rule. Much of the fault leading to this result can be traced to the widespread perception that acoustics is a black art. In fact, scientific acoustics as developed in the last century is a well-defined engineering practice that can lead to predictable excellent results.
A basic, non-engineering understanding of acoustics will help building owners, theater managers, ministers and teachers of music, performers, and other professionals to achieve their goals of excellent acoustics in venues with which they work. Performers having a basic understanding of acoustics will be able to make the most of the acoustics of the venue in which they perform.
This book helps those responsible for providing good acoustics in performance and worship spaces to understand the variables and choices entailed in proper acoustic design for performance and worship. Practicing acoustical consultants will find the book a useful reference as well. The level of presentation is comfortable and straightforward without being simplistic. If correct acoustical principles are incorporated into the design, renovation, and maintenance of performance and worship venues, good acoustics will be the result.
As demand for solar panel installation has risen sharply, especially for installations larger than balcony power plants, the order books of solar companies are full. If you ask for a quote today, you may have to wait a while, if your request isn't simply postponed indefinitely. Another consequence of the solar boom is that some companies are charging very high prices for installations.
Yet there is an obvious and radical solution to the problem of excessive prices: Do it yourself, as the English say. The price of materials is currently affordable, and it's the ideal time for those who do the work themselves. They couldn't save more. Add to this the satisfaction of doing something useful, both economically and ecologically, and the pleasure of building yourself.
In this special issue, you'll find a wide selection of Elektor assemblies, from solar panel controllers to solar water heaters and solar panel orientation systems. The issue also contains practical information on solar panel installation and the technology behind them. Finally, there are a number of articles on the subject of balcony power plants, from how to install them to how to connect them to the Internet...
Contents
BASICS
Dimensioning Photovoltaic Panel ArraysAn introduction to photovoltaic energy and the commonest techniques,followed by simplified calculation models and setup guidelines.
Light Sensor TechnologyMeasuring daylight using LEDs.
Solar Power Made SimpleSolar charging with and without a controller.
Cable Cross-sections and Energy Losses in Solar SystemsKey considerations on the minimum values to respect for electricalcurrent in solar panel cabling.
Solar ModulesEverything you always wanted to know about solar panels...
Ideal Diode ControllerDiode Circuits with Low Power Dissipation.
TIPS
Tracking for Solar Modules
zBot Solar/Battery Power Supply
Solar Cell Array Charger with Regulator
Solar Cell Voltage Regulator
Solar-Powered Night Light
Alternative Solar Battery Charger
PROJECTS
Energy LoggerMeasuring and Recording Power Consumption.
Tiny Solar SupplySunlight In, 3.3 V Out.
A Do-It-Yourself DTURead Data from Small Inverters by μC.
Solar ChargerPortable energy for people on the move.
Solar Thermal Energy RegulatorMaximum power point tracking explored.
2-amp Maximum Power Tracking ChargerSolar Power To The Max.
Computer-driven HeliostatFollow the sun or the stars.
Garden LightingUsing solar cells.
Solar Panel Voltage Converter for IoT DevicesYes we CAN exploit indoor lighting.
Travel ChargerFree power in the mountains.
Solar Cell Battery Charger/MonitorWith protection against deep discharge.
Solar-powered Battery ChargerPIC12C671 avoids overcharging and deep charging.
Converters for Photovoltaic PanelsContributed by TME (Transfer MultisortElektronik).
Solar Charging RegulatorFor panels up to 53 watts.
Solar-Powered ChargerFor lead-acid batteries.
CAN Bus + Arduino for Solar PV Cell MonitoringDetect and locate serviceable panels in large arrays.
Balcony Power Plant 2.0The latest: solar panels, installation and inverters
With Examples for Raspberry Pi Pico and ESP32
Creating and programming small electronic systems is now easier than ever before. With inexpensive development boards and modern software tools, anyone curious about embedded design can quickly move from an idea to a working piece of hardware. At the heart of this change is MicroPython—a clear, interactive, and beginner-friendly way to program microcontrollers while still remaining closely connected to the underlying electronics.
This book introduces embedded programming through MicroPython on popular platforms such as the Raspberry Pi Pico and the ESP32. You will discover how to use microcontrollers for reading inputs, processing data, and controlling outputs in a predictable, real-time loop. With just a few lines of code, you can blink LEDs, read sensors, drive motors, and communicate with the outside world. The interactive REPL programming interface encourages experimentation and fast learning, making concepts tangible from the very first chapter.
While different boards offer different capabilities, they all share the same core principles. Timers, GPIO, analog I/O, PWM, interrupts, and communication interfaces form the foundation of every embedded system.
By focusing on these universal building blocks, this book helps you build skills that transfer across platforms and scale naturally toward more advanced development. Whether you are a beginner or an experienced programmer entering embedded systems, you will find that working with MicroPython is both practical and genuinely enjoyable.
Learn, Build, and Understand Electronics – with Elektor
Projects, Expert Knowledge, Archive Access, and Exclusive Discounts – All in One Membership
Would you like to learn electronics, develop your own circuits, and gain a better understanding of modern technologies? Elektor Magazine has been one of the leading sources of information for electronics engineers, developers, start-ups, and companies for 65 years. With an Elektor Green Membership, you get:
✅ The international electronics magazine Elektor (in digital format)
✅ Access to the Elektor archive with 65 years of electronics know-how
✅ DIY projects, tested circuits, in-depth reviews and tutorials
✅ Exclusive member discounts at Elektor.com
Why Elektor?
For 65 years, Elektor has stood for in-depth electronics knowledge, practical projects, and innovative technologies.
From microcontrollers and embedded systems to Raspberry Pi, Arduino, and ESP32, as well as IoT, AI, measurement technology, audio, RF, and robotics, Elektor covers the key platforms and application areas of modern electronics.
Whether you are a beginner, maker, or professional – Elektor helps you take your skills to the next level.
Who Is This Membership for?
Beginners – Start your journey into electronics with clear fundamentals and first projects
Makers – Discover new projects, ideas, and inspiration for your own developments
Professionals & Engineers – Stay up to date with modern technologies and deepen your expertise
Your Benefits at a Glance
Magazine (Digital) – Receive every issue digitally, delivered straight to your inbox
65 Years of Electronics Knowledge – Access the extensive Elektor archive anytime (since 1974)
Hands-on Projects – Turn your ideas into reality with guides, circuits, and tutorials
Exclusive Discounts – Save on every purchase at Elektor.com
Unlock All Elektor Benefits Today!
Free Membership
Green Membership
❌ 8x Elektor Magazine (Digital Edition) as PDF
✅ 8x Elektor Magazine (Digital Edition) as PDF
❌ 12 Months of Access to the Full Elektor Archive
✅ 12 Months of Access to the Full Elektor Archive
❌ Access to Over 5,000 Gerber Files
✅ Access to Over 5,000 Gerber Files
❌ 10% Member Discount at Elektor.com
✅ 10% Member Discount at Elektor.com
✅ Read Elektor weekly every Friday
✅ Read Elektor weekly every Friday
ℹ️ Do you prefer reading Elektor Magazine in print? Find out everything about the Elektor Gold Membership (Print) here.
Praktische Anwendungen und Projekte mit Arduino, ESP32 und RP2040
Tauchen Sie ein in die faszinierende Welt der Regelungstechnik mit Arduino und ESP32! Dieses Buch bietet Ihnen einen praxisnahen Einstieg in die klassischen und modernen Methoden der Regelung, darunter PID-Regler, Fuzzy-Logik und Sliding-Mode-Regler.
Im ersten Teil lernen Sie die Grundlagen der beliebten Arduino-Controller, wie den Arduino Uno und den ESP32, sowie die Integration von Sensoren für Temperatur- und pH-Messung (NTC, PT100, PT1000, pH-Sensor). Sie erfahren, wie diese Sensoren in verschiedenen Projekten eingesetzt werden und wie Sie Daten auf einem Nextion TFT-Display visualisieren.
Weiter geht es mit der Einführung in Stellglieder wie MOSFET-Schalter, H-Brücken und Solid-State-Relais, die zur Steuerung von Motoren und Aktoren verwendet werden. Sie lernen, Regelstrecken zu analysieren und zu modellieren, einschließlich PT1- und PT2-Regelungen.
Der Schwerpunkt des Buches liegt auf der Implementierung von Fuzzy- und PID-Reglern zur Regelung von Temperatur und DC-Motoren. Dabei werden sowohl der Arduino Uno als auch der ESP32 eingesetzt. Zudem wird der Sliding-Mode-Regler vorgestellt.
Im vorletzten Kapitel erkunden Sie die Grundlagen neuronaler Netze und lernen, wie maschinelles Lernen auf einem Arduino eingesetzt werden kann. Im letzten Kapitel gibt es noch ein praktisches Beispiel für einen Fuzzy-Regler zur Stromeinspeisung ins Hausnetz.
Dieses Buch ist die perfekte Wahl für Ingenieure, Studierende und Elektroniker, die ihre Projekte mit innovativen Regelungstechniken erweitern möchten.
Hands-on in more than 50 projects
STM32 Nucleo family of processors are manufactured by STMicroelectronics. These are low-cost ARM microcontroller development boards. This book is about developing projects using the popular STM32CubeIDE software with the Nucleo-L476RG development board. In the early Chapters of the book the architecture of the Nucleo family is briefly described.
The book covers many projects using most features of the Nucleo-L476RG development board where the full software listings for the STM32CubeIDE are given for each project together with extensive descriptions. The projects range from simple flashing LEDs to more complex projects using modules, devices, and libraries such as GPIO, ADC, DAC, I²C, SPI, LCD, DMA, analogue inputs, power management, X-CUBE-MEMS1 library, DEBUGGING, and others. In addition, several projects are given using the popular Nucleo Expansion Boards. These Expansion Boards plug on top of the Nucleo development boards and provide sensors, relays, accelerometers, gyroscopes, Wi-Fi, and many others. Using an expansion board together with the X-CUBE-MEMS1 library simplifies the task of project development considerably.
All the projects in the book have been tested and are working. The following sub-headings are given for each project: Project Title, Description, Aim, Block Diagram, Circuit Diagram, and Program Listing for the STM32CubeIDE.
In this book you will learn about
STM32 microcontroller architecture;
the Nucleo-L476RG development board in projects using the STM32CubeIDE integrated software development tool;
external and internal interrupts and DMA;
DEBUG, a program developed using the STM32CubeIDE;
the MCU in Sleep, Stop, and in Standby modes;
Nucleo Expansion Boards with the Nucleo development boards.
What you need
a PC with Internet connection and a USB port;
STM32CubeIDE software (available at STMicroelectronics website free of charge)
the project source files, available from the book’s webpage hosted by Elektor;
Nucleo-L476RG development board;
simple electronic devices such as LEDs, temperature sensor, I²C and SPI chips, and a few more;
Nucleo Expansion Boards (optional).
The State of Hollow State Audio in the Second Decade of the 21st Century
Vacuum-tube (or valve, depending upon which side of the pond you live on) technology spawned the Age of Electronics early in the 20th Century. Until the advent of solid-state electronics near mid-century, hollow-state devices were the only choice. But following the invention of the transistor (after their process fell to reasonable levels), within a couple of decades, the death of vacuum tubes was widely heralded. Yet here we are some five decades later, and hollow-state equipment is enjoying something of a comeback, especially in the music and high-end audio industries.
Many issues surround hollow-state audio:
Does it produce—as some claim—better sound? If so, is there science to back up these claims?
How do hollow-state circuits work?
How do you design hollow-state audio circuits?
If hollow-state equipment fails, how do you go about troubleshooting and repairing it?
Can we recreate some of the classic hollow-state audio devices for modern listening rooms and recording studios?
How can we intelligently modify hollow-state amplifiers to our taste?
These and other topics are covered in The State of Hollow State Audio.
High-Performance LoRa Communication Device
The Elecrow ThinkNode M5 is a compact, portable LoRa communication device designed for off-grid messaging, location sharing, and outdoor use. Powered by an ESP32-S3 processor and an SX1262 LoRa chip, it comes pre-installed with Meshtastic firmware and can be configured conveniently via Bluetooth using the official Meshtastic app.
The integrated multi-GNSS module supports GPS, GLONASS, BeiDou, and QZSS for reliable positioning and location sharing. Messages and device information are displayed on the energy-efficient 1.54-inch e-paper screen, while the built-in 1,200 mAh rechargeable battery enables extended mobile operation.
With its integrated LoRa antenna, compact housing, RTC, and support for both Meshtastic and MeshCore firmware, the ThinkNode M5 is a practical communication solution for hiking, camping, remote locations, and emergency situations where conventional mobile networks are unavailable.
Features
LoRa communication
Multi-GNSS positioning
1,200 mAh rechargeable battery
1.54-inch e-paper display
Built-in RTC
Compatible with MeshCore
Compatible with Meshtastic
Specifications
Main Processor (ESP32-S3)
CPU/SoC
Xtensa 32-bit LX7 dual-core processor, clocked at up to 240 MHz
System Memory
512 KB SRAM, 8 MB PSRAM
Storage
4 MB Flash, 384 KB ROM
Firmware
Meshtastic firmware is fully compatible, and the signal is transmitted in LoRa mode
EPD (Electronic Paper Display)
Display Size
1.54 inch EPD (monochrome Ink screen)
Display Materials
E-lnk (Electronic Ink)
Resolution
200 x 200
Driver Chip
SSD1681 (via SPI or I²C interface)
Global Fresh Time
2s
Wireless Communication
Bluetooth
Bluetooth Low Energy and Bluetooth 5.0 (phone configuration)
LoRa
SX1262 LoRa Module, EU 868 MHz(external antenna)
Hardware
Interfaces
USB-C, RP-SMA
Function
GPS Location (GPS, GLONASS, BeiDou, QZSS), EPD Display, RTC, USB 2.0, PMU power management (built-in 1200 mAh lithium battery), buzzer, etc.
Button
Knob Switch, Function Button, Page Turn Button, GPS Switch, Reset Button
LED Indicator
Power supply, GPS/LoRa indication
Others
Power Input
5 V/1 A, supports USB or lithium battery power supply
Power consumption
The maximum working current is about 340 mA (CPU + LoRa module), and the low power consumption is about 34 uA
Operating Temperature
-10~50°C
Storage Temperature
-20~60°C
Relative humidity
10-95%, @ 40°C (non-condensing)
Enclosure
ABS Plastic
Dimensions
82 x 51.6 x 26.3 mm
Weight
81 g
Included
1x Elecrow ThinkNode M5
1x LoRa antenna
1x USB-C cable
1x Manual
Downloads
Manual
Whatever the methods or even then financial means you have to make your circuits work, the power supply should rank high if not Number One in your considerations. The design block simply called “power supply” is hugely underrated both in electronics creation and repair. Yet, the “PSU” has enormous diversity and comes in wildly differing guises like AC/DC, generator, battery (rechargeable or not), PV panel, benchtop, linear or switch-mode, to mention but a few. The output ranges are also staggering like nano-amps to kiloamps and the same for voltages.This special covers the features and design aspects of power supplies.ContentsBasics
Battery ManagementWhat to be aware of when using (Lithium) batteries.
Fixed-Voltage Power Supply using Linear RegulatorsThe best result right after batteries.
Light Energy HarvestingA small solar panel is used in an energy harvesting project to manage and charge four AAA cells.
Mains Powered Adapter DesignBasic circuits and tips for transformers, rectification, filtering and stabilization.
LM317 Soft StartThe high inrush current pulse should be avoided.
Controllable RectifiersSome suggestions to keep the power loss in the linear regulator as low as possible.
Components
Worksheet: The LM117 / LM217 / LM317 Voltage Regulators
SupercapsLow voltage but lots of current… or not?
Reviews
JOY-iT RD6006 Benchtop Power Supply Kit
Siglent SDL1020X Programmable DC Electronic Load
Projects
Balcony Power PlantDIY solar balcony = speedy payback!
DIY LiPo Supercharger KitFrom handcrafted to mass market
Dual-Anode MOSFET ThyristorFaster and less wasteful than the old SCR
Battery JuicerDo not throw away, squeeze!
High-Voltage Power Supply with Curve TracerGenerate voltages up to 400 V and trace characteristics curves for valves and transistors
High Voltage Supply for RIAAFor RIAA tube preamps and other applications.
MicroSupplyA lab power supply for connected devices
Phantom Power Supply using Switched CapacitorsVoltage tripler using three ICs
The SMPS800RE Switch-Mode Supply for the Elektor Fortissimo-100Reliable, light and affordable
Soft Start for PSUBe nice to your power supply – and its load
UniLab 20-30 V, 3 A compact switch-mode lab power supply
Tips
Soft Start for Step-Down Switching Regulators
Low Loss Current Limit
Powerbank Surprise
A Virtual Ground
Battery Maintainer
Battery Pack Discharger
Connecting Voltage Regulators in Parallel
Program and Build Raspberry Pi 5 Based Ham Station Utilities with the RTL-SDR
The RTL-SDR devices (V3 and V4) have gained popularity among radio amateurs because of their very low cost and rich features. A basic system may consist of a USB based RTL-SDR device (dongle) with a suitable antenna, a Raspberry Pi 5 computer, a USB based external audio input-output adapter, and software installed on the Raspberry Pi 5 computer. With such a modest setup, it is possible to receive signals from around 24 MHz to over 1.7 GHz.
This book is aimed at amateur radio enthusiasts and electronic engineering students, as well as at anyone interested in learning to use the Raspberry Pi 5 to build electronic projects. The book is suitable for both beginners through experienced readers. Some knowledge of the Python programming language is required to understand and eventually modify the projects given in the book. A block diagram, a circuit diagram, and a complete Python program listing is given for each project, alongside a comprehensive description.
The following popular RTL-SDR programs are discussed in detail, aided by step-by-step installation guides for practical use on a Raspberry Pi 5:
SimpleFM
GQRX
SDR++
CubicSDR
RTL-SDR Server
Dump1090
FLDIGI
Quick
RTL_433
aldo
xcwcp
GPredict
TWCLOCK
CQRLOG
klog
Morse2Ascii
PyQSO
Welle.io
Ham Clock
CHIRP
xastir
qsstv
flrig
XyGrib
FreeDV
Qtel (EchoLink)
XDX (DX-Cluster)
WSJT-X
The application of the Python programming language on the latest Raspberry Pi 5 platform precludes the use of the programs in the book from working on older versions of Raspberry Pi computers.
Complete ESP32 microcontroller learning course featuring a custom-designed MCU expansion board, hands-on projects, and a comprehensive online guide – perfect for learning hardware, programming, and connectivity step by step.
A Practical Introduction to Embedded Systems with the ESP32
This course is designed for readers who are new to embedded systems and looking for a structured, example-driven way to get started. If you’ve explored general-purpose electronics or Arduino-based materials but found them too broad or lacking in practical guidance, this course offers a more focused alternative.
Using the "ESP32 by Example Kit" (EEK) – a compact and affordable set of components featuring LEDs, sensors, an OLED display, and a motion processor – you’ll work with a consistent hardware setup throughout the course. Once assembled, the EEK stays mostly unchanged, allowing you to concentrate on learning and experimentation without constant reconfiguration.
Topics include:
Understanding and programming the ESP32 microcontroller
Writing and deploying code with the Arduino IDE
Exploring cyber-physical systems, culminating in basic drone control
No prior experience with Arduino or embedded development is required. Each section features hands-on examples and mini-projects designed to reinforce key concepts and inspire deeper exploration. By the end of the course, you’ll be able not only to reproduce the book’s examples but also to build on them with your own ideas and applications.
Whether you're interested in embedded programming, interactive systems, or introductory drone control, this course provides a clear and practical path to getting started.
What you'll learn?
Embedded programming with the ESP32 using the Arduino IDE
Real-time sensor input and control via buttons, LEDs, and displays
Gesture-based interaction using the MPU6050 motion sensor
Bluetooth gamepad integration and drone control simulation
Wi-Fi and UDP networking, local web servers, and NTP
MQTT communication with cloud platforms like AWS and Arduino IoT
How to build and deploy full-featured IoT systems
Perfect for
Students and self-learners exploring embedded systems
Makers and IoT enthusiasts looking to improve their hardware skills
Educators and trainers seeking ready-to-teach material
Developers moving beyond Raspberry Pi or Arduino basics
Support when you need it
Access to instructors via Elektor Academy
Helpful community forums and essential documentation
What's inside the Box (Course)?
New 384-page book: "ESP32 by Example" (valued at €45)
Elektor ESP32 by Example Kit (EEK): Microcontroller Extension Board with 6 LEDs and 6 Buttons installed + OLED Display, MPU6050 3-axis Accelerometer and Gyroscope Module (valued at €40)
Adafruit HUZZAH32 – ESP32 Feather MCU Board (valued at €30)
ESP32 Cheap Yellow Display Board (valued at €25)
DHT11 Humidity & Temperature Sensor
Breadboard
Jumper wires
USB-C cable
Access to the full course on the Elektor Academy Pro Learning Platform
Instructional videos
Downloadable Arduino project files for every module
Learning Material (of this Box/Course)
▶ Click here to open
Module 1 – Getting Started with the ESP32 & EEK
Module 2 – Digital Output – LEDs and GPIO
Module 3 – Switches and Input Handling
Module 4 – EEK and PWM
Module 5 – OLED and Display Output
Module 6 – Motion Sensing with the MPU6050
Module 7 – Capstone Project (EEK in Action)
Module 8 – WiFi and Web Control with ESP32
Module 9 – Cloud Concepts using EEK
Module 10 – Hands-on: Arduino IoT Cloud and EEK
Module 11 – BlueTooth and EEK GamePad Integration
Module 12 – Why Drones?
Module 13 – Drone Simulator Concepts
Module 14 – Simple Drone Flight Control
Module 15 – Real-Time Drone Flight Control
Module 16 – Drone Control Mini-Projects
Module 17 – Middleware and Python Scripting
Module 18 – Python Applications for Drone Control
Module 19 – Capstone EEK Control Project and Presentation
About the Author
Dr. Jim Solderitsch is an educator, software architect, systems developer, and cybersecurity researcher with a focus on cyber-physical systems. He currently serves as an Adjunct Professor in Computing Sciences at Villanova University in Pennsylvania.
What is Elektor Academy Pro?
Elektor Academy Pro delivers specialized learning solutions designed for professionals, engineering teams, and technical experts in the electronics and embedded systems industry. It enables individuals and organizations to expand their practical knowledge, enhance their skills, and stay ahead of the curve through high-quality resources and hands-on training tools.
From real-world projects and expert-led courses to in-depth technical insights, Elektor empowers engineers to tackle today’s electronics and embedded systems challenges. Our educational offerings include Academy Books, Pro Boxes, Webinars, Conferences, and industry-focused B2B magazines – all created with professional development in mind.
Whether you're an engineer, R&D specialist, or technical decision-maker, Elektor Academy Pro bridges the gap between theory and practice, helping you master emerging technologies and drive innovation within your organization.
Elektor GREEN and GOLD members can download their digital edition here.
Not a member yet? Click here.
The ESP-BLASTA Mini ESP32 Rocket Drone That Flies 100 km/h+
Wireless Workshop (1)Radio Modules Unlocked: 433 MHz CC1101 Sub-GHz Transceiver
AM TransmitterWith Square/Sine Wave Generator on Raspberry Pi Pico
STM32Cube Innovation ChallengeCompete with Your Best STM32C5 Design
CoffeeCallerHow a Long Hallway Led to a Custom Mesh-Networked PCB
AudiotronicsTotal Harmonic Distortion
Elektor at 65Projects from Septembers and Octobers Past
Bluetooth Channel Sounding for Asset TrackingCentimeter-Level Precision Ranging for Next-Generation IoT
2026: An AI OdysseyQuantum Computing Is Not the Next GPU
Protecting the Cloud Demands Security at the Edge
First Experiences with the HackRF ProPractical Tests with the New SDR Hardware
Modem Upgrade from GPRS/2G to LTE/4GUsing a Wireless Alarm Control Panel as an Example
Loop Antenna with RF BricksPart 1: A DIY Shortwave Antenna with Adjustable Directivity
Internet Radio to AM ConverterUsing an ESP32-S3 as Transmitter
Err-lectronics
mioty — An OverviewFraunhofer’s Approach to LPWAN
Workbench WisdomPractical Tips from Experts
Walter, the Compact IoT ModulePart 2: Accessing Weather and Data Services