Programming and Projects for the Minima and WiFi
Based on the low-cost 8-bit ATmega328P processor, the Arduino Uno R3 board is likely to score as the most popular Arduino family member so far, and this workhorse has been with us for many years. Recently, the new Arduino Uno R4 was released, based on a 48-MHz, 32-bit Cortex-M4 processor with a huge amount of SRAM and flash memory. Additionally, a higher-precision ADC and a new DAC are added to the design. The new board also supports the CAN Bus with an interface.
Two versions of the board are available: Uno R4 Minima, and Uno R4 WiFi. This book is about using these new boards to develop many different and interesting projects with just a handful of parts and external modules, which are available as a kit from Elektor. All projects described in the book have been fully tested on the Uno R4 Minima or the Uno R4 WiFi board, as appropriate.
The project topics include the reading, control, and driving of many components and modules in the kit as well as on the relevant Uno R4 board, including
LEDs
7-segment displays (using timer interrupts)
LCDs
Sensors
RFID Reader
4×4 Keypad
Real-time clock (RTC)
Joystick
8×8 LED matrix
Motors
DAC (Digital-to-analog converter)
LED matrix
WiFi connectivity
Serial UART
CAN bus
Infrared controller and receiver
Simulators
… all in creative and educational ways with the project operation and associated software explained in great detail.
Programming and Projects for the Minima and WiFi
Based on the low-cost 8-bit ATmega328P processor, the Arduino Uno R3 board is likely to score as the most popular Arduino family member so far, and this workhorse has been with us for many years. Recently, the new Arduino Uno R4 was released, based on a 48-MHz, 32-bit Cortex-M4 processor with a huge amount of SRAM and flash memory. Additionally, a higher-precision ADC and a new DAC are added to the design. The new board also supports the CAN Bus with an interface.
Two versions of the board are available: Uno R4 Minima, and Uno R4 WiFi. This book is about using these new boards to develop many different and interesting projects with just a handful of parts and external modules, which are available as a kit from Elektor. All projects described in the book have been fully tested on the Uno R4 Minima or the Uno R4 WiFi board, as appropriate.
The project topics include the reading, control, and driving of many components and modules in the kit as well as on the relevant Uno R4 board, including
LEDs
7-segment displays (using timer interrupts)
LCDs
Sensors
RFID Reader
4×4 Keypad
Real-time clock (RTC)
Joystick
8×8 LED matrix
Motors
DAC (Digital-to-analog converter)
LED matrix
WiFi connectivity
Serial UART
CAN bus
Infrared controller and receiver
Simulators
… all in creative and educational ways with the project operation and associated software explained in great detail.
The Elektor Milliohmmeter Adapter uses the precision of a multimeter to measure very low resistance values. It is an adapter that converts a resistance into a voltage that can be measured with a standard multimeter.
The Elektor Milliohmmeter Adapter can measure resistances below 1 mΩ using a 4-wire (Kelvin) method. It is useful for locating short circuits on printed circuit boards (PCB).
The adapter features three measurement ranges – 1 mΩ, 10 mΩ, and 100 mΩ – selectable via a slide switch. It also includes onboard calibration resistors. The Elektor Milliohmmeter Adapter is powered by three 1.5 V AA batteries (not included).
Specifications
Measurement ranges
1 mΩ, 10 mΩ, 100 mΩ, 0.1%
Power supply
3x 1.5 V AA batteries (not included)
Dimensions
103 x 66 x 18 mm (compatible with Hammond 1593N-type enclosure, not included)
Special feature
On-board calibration resistors
Downloads
Documentation
Pull Down Lever For Highest Score!
This Elektor Circuit Classic from 1984 shows a playful application of CMOS 400x series logic ICs in combination with LEDs, a highly popular combination at the time. The project imitates a spinning-digit type slot machine.
The Game
To play the game, first agree on the number of rounds. Player 1 actuates the switch lever as long as desired and releases it. The LEDs then show the score which is the sum of the 50-20-10-5 digits lit up. If the Play Again! LED lights, Player 1 has another, “free” round. If not, it’s Player 2’s turn. The players keep tab of their scores, and the highest score wins.
Features
LEDs Indicate Score
Multi-Player and Play Again!
Elektor Heritage Circuit Symbols
Tried & Tested by Elektor Labs
Educational & Geeky Project
Through-Hole Parts Only
Included
Printed Circuit Board
All Components
Wooden Stand
Bill of Materials
Resistors (5%, 250 mW)
R1,R2,R3,R4 = 100kΩ
R5,R6,R7,R8,R9,R10 = 1kΩ
Capacitors
C1 = 4.7nF, 10%, 50V, 5mm
C2 = 4.7μF, 10%, 63V, axial
C3,C4 = 100nF, 10 %, 50V, ceramic X7R, 5mm
Semiconductors
LED1-LED6 = red, 5mm (T1 3/4)
IC1 = 74HC4024
IC2 = 74HC132
Miscellaneous
S1 = switch, toggle, 21mm lever, SPDT, momentary
S2 = switch, tactile, 24V, 50mA, 6x6mm
S3 = switch, slide, SPDT
IC1,IC2 = IC socket, DIP14
BT1 = PCB-mount CR2032 battery retainer clip
Desktop Stand
PCB 230098-1
Not included: BT1 = CR2032 coin cell battery
A Retro Roll with a Neon Soul
LED-based dice are common, but their light is cold. Not so for this electronic neon dice, which displays its value with the warm glow of neon lamps. It is perfect for playing games on cold, dark winter evenings. The pips of the dice are neon lamps and the random number generator has six neon lamps to show that it is working.
Even though the dice has an on-board 100-V power supply, it is completely safe. As with all Elektor Classic products, the dice too has its circuit diagram printed on the front while an explanation of how the circuit works can be found on the rear side.
The Neon Lamp Dice comes as a kit of easy-to-solder through-hole parts. The power supply is a 9-V battery (not included).
Features
Warm Vintage Glow
Elektor Heritage Circuit Symbols
Tried & Tested by Elektor Labs
Educational & Geeky Project
Through-Hole Parts Only
Included
Printed Circuit Board
All Components
Wooden Stand
Required
9 V battery
Component List
Resistors (THT, 150 V, 0.25 W)
R1, R2, R3, R4, R5, R6, R14 = 1 MΩ
R7, R8, R9, R10, R11, R12 = 18 kΩ
R13, R15, R16, R17, R18, R21, R23, R24, R25, R26, R28, R30, R33 = 100 kΩ
R32, R34 = 1.2 kΩ
R19, R20, R22, R27, R29 = 4.7 kΩ
R31 = 1 Ω
Capacitors
C1, C2, C3, C4, C5, C6 = 470 nF, 50 V, 5 mm pitch
C7, C9, C11, C12 = 1 µF, 16 V, 2 mm pitch
C8 = 470 pF, 50 V, 5 mm pitch
C10 = 1 µF, 250 V, 2.5 mm pitch
Inductors
L1 = 470 µH
Semiconductors
D1, D2, D3, D4, D5, D6, D7 = 1N4148
D8 = STPS1150
IC1 = NE555
IC2 = 74HC374
IC3 = MC34063
IC4 = 78L05
T1, T2, T3, T4, T5 = MPSA42
T6 = STQ2LN60K3-AP
Miscellaneous
K1 = PP3 9 V battery holder
NE1, NE2, NE3, NE4, NE5, NE6, NE7, NE8, NE9, NE10, NE11, NE12, NE13 = neon light
S2 = Miniature slide switch
S1 = Pushbutton (12 x 12 mm)
The Elektor ESP32 Energy Meter is a device designed for real-time energy monitoring and smart home integration. Powered by the ESP32-S3 microcontroller, it offers robust performance with modular and scalable features.
The device uses a 220 V-to-12 V step-down transformer for voltage sampling, ensuring galvanic isolation and safety. Its compact PCB layout includes screw-type terminal blocks for secure connections, a Qwiic connector for additional sensors, and a programming header for direct ESP32-S3 configuration. The energy meter is compatible with single-phase and three-phase systems, making it adaptable for various applications.
The energy meter is simple to set up and integrates with Home Assistant, offering real-time monitoring, historical analytics, and automation capabilities. It provides accurate measurements of voltage, current, and power, making it a valuable tool for energy management in homes and businesses.
Features
Comprehensive Energy Monitoring: Get detailed insights into your energy usage for smarter management and cost savings.
Customizable Software: Tailor functionality to your needs by programming and integrating custom sensors.
Smart Home Ready: Compatible with ESPHome, Home Assistant, and MQTT for full Smart Home integration.
Safe & Flexible Design: Operates with a 220 V-to-12 V step-down transformer and features a pre-assembled SMD board.
Quick Start: Includes one Current Transformer (CT) sensor and access to free setup resources.
Specifications
Microcontroller
ESP32-S3-WROOM-1-N8R2
Energy Metering IC
ATM90E32AS
Status Indicators
4x LEDs for power consumption indication2x Programmable LEDs for custom status notifications
User Input
2x Push buttons for user control
Display Output
I²C OLED display for real-time power consumption visualization
Input Voltage
110/220 V AC (via step-down transformer)
Input Power
12 V (via step-down transformer or DC input)
Clamp Current Sensor
YHDC SCT013-000 (100 A/50 mA) included
Smart Home Integration
ESPHome, Home Assistant, and MQTT for seamless connectivity
Connectivity
Header for programming, Qwiic for sensor expansion
Applications
Supports single-phase and three-phase energy monitoring systems
Dimensions
79.5 x 79.5 mm
Included
1x Partly assembled board (SMDs are pre-mounted)
2x Screw terminal block connerctors (not mounted)
1x YHDC SCT013-000 current transformer
Required
Power transformer not included
Downloads
Datasheet (ESP32-S3-WROOM-1)
Datasheet (ATM90E32AS)
Datasheet (SCT013-000)
Frequently Asked Questions (FAQ)
From Prototype to Finished Product
What started as an innovative project to create a reliable and user-friendly energy meter using the ESP32-S3 microcontroller has evolved into a robust product. Initially developed as an open-source project, the ESP32 Energy Meter aimed to provide precise energy monitoring, smart home integration and more. Through meticulous hardware and firmware development, the energy meter now stands as a compact, versatile solution for energy management.
Build Your Own Vintage Radio Broadcaster
The Elektor AM Transmitter Kit allows streaming audio to vintage AM radio receivers. Based on a Raspberry Pi Pico microcontroller module, the AM Transmitter can transmit on 32 frequencies in the AM band, from 500 kHz up to 1.6 MHz in 32 steps of approx. 35 kHz.
The frequency is selected with a potentiometer and shown on a 0.96" OLED display. A pushbutton allows toggles the transmitting mode between On and Off. The range of the transmitter depends on the antenna. The onboard antenna provides a range of a few centimeters, requiring the AM Transmitter to be placed close to or inside the radio. An external loop antenna (not included) can be connected to increase the range.
The Elektor AM Transmitter Kit comes as a kit of parts that you must solder to the board yourself.
Features
The board is compatible with a Hammond 1593N enclosure (not included).A 5 VDC power supply with micro-USB connector (e.g., an old phone charger) is needed to power the kit (not included). Current consumption is 100 mA.
The Arduino software (requiring Earle Philhower’s RP2040 Boards Package) for the Elektor AM Transmitter Kit plus more information is available at the Elektor Labs page of this project.
Component List
Resistors
R1, R4 = 100 Ω
R2, R3, R8 = 10 kΩ
R5, R6, R9, R10, R11 = 1 kΩ
R7 = optional (not included)
P1 = potentiometer 100 kΩ, linear
Capacitors
C1 = 22 µF 16V
C2, C4 = 10 nF
C3 = 150 pF
Miscellaneous
K1 = 4×1 pin socket
K2, K3 = 3.5 mm socket
Raspberry Pi Pico
pushbutton, angle mount
0.96" monochrome I²C OLED display
PCB 150292-1
Elektor GREEN and GOLD members can download their digital edition here.
Not a member yet? Click here.
Project Update: ESP32-Based Energy MeterNext Steps in Prototyping
Optimizing Balcony Power PlantsConsiderations, Interesting Facts, and Calculations
ESP32 With OpenDTU for Balcony Power PlantsRead Data from Small Inverters Via MCUs
Variable Linear Power Supply Ensemble0…50 V / 0…2 A + Dual Symmetrical Supply
Energy Storage Today and TomorrowAn Interview With Simon Engelke
2024: An AI OdysseyIt’s Not Letting Up
Bluetooth LE on the STM32A Way to Read Measurements Remotely
Human-Centric Smart Kitchen Grocery Container
MAUI: Programming for PC, Tablet, and SmartphoneThe New Framework in Theory and Practice
ChatMagLevThe AI Way of Levitation
Simple PV Power RegulatorBuild Your First, Fully Functional PV Energy Management System
Cold-Cathode DevicesPeculiar Parts, the Series
From Life’s ExperienceNostalgia
Starting Out in Electronics……Looking at FETs
CAN Bus Tutorial for the Arduino UNO R4Two UNO R4s Hop on the Bus!
Infographics: Power & Energy
Comprehensive Design and Development SupportArrow Engineering Services
Comparing Power Density and Power Efficiency
Aluminium Electrolytic CapacitorsInterference Potential in Audio Technology
USB Test and MeasurementThe Fnirsi FNB58
The Pixel Pump Pick-and-Place ToolSimplifying Manual SMT Board Assembly
HomeLab ToursNot So Long Ago, in a Far-Away Country...
“In the world of ethics in electronics, even small steps can make a significant impact.”
Ethics in ElectronicsThe OECD Guidelines and Germany’s Supply Chain Due Diligence Act
Chadèche: Smart Ni-MH Charger/DischargerA Reader’s Project in Brief
Err-lectronicsCorrections, Updates and Readers’ Letters
Elektor GREEN and GOLD members can download their digital edition here.
Not a member yet? Click here.
STM32 Wireless Innovation Design Contest Winners
In-Circuit LC MeterA Prototype Study
The AmpVolt Modular DC Power Meter (Part 1)Measure DC Power and Energy Consumption Up to 50 V and 5 A
embedded world 2024
Repairing Electronic EquipmentTools, Techniques and Tips
Starting Out in Electronics…...Continues the Opamp Theory
A Simple DDS Signal GeneratorDirect Digital Synthesis in Its Purest Form
Sparkplug at a GlanceA Specification for MQTT Data
The CRTCPeculiar Parts, the Series
Radar-Controlled LightingAutomatic Stairway Light With Human Presence Detection
Digital Bubble Level and Active Stroboscopic Disc for TurntablesFine-Tune Your Record Player With This All-In-One Tool
Open Source and Its Significance for the Electronics Industry (2)
M12 Circular Connector With A-codingFirst Choice for Industrial Applications
The Arduino-Inside Measurement LabAn 8-in-1 Test & Measurement Instrument for the Electronics Workbench
Sound Card Performs Gain/Phase and Impedance AnalysisFor Frequencies From 100 Hz to 90 kHz
Measuring pH Value With the Arduino UNO R4Check the Quality of Your Water
From Life’s ExperiencePangpong Butt Launcher
FNIRSI 1014D Digital Storage OscilloscopeGood Performance for Tight Budgets
2024: An AI OdysseyGetting Object Detection Up and Running
10 MHz Reference GeneratorHighly Accurate, With Distributor and Galvanic Isolation
Project Update #2: ESP32-Based Energy MeterSome Enhancements
Err-lectronicsCorrections, Updates, and Readers’ Letters
An Interview with Eben Upton, CEO of Raspberry PiRaspberry Pi 5 and Beyond
Vision and Mission Elektor believes that innovations in electronics will lead to a better world. Elektor is a multi-faceted platform in the applied electronics industry that unites hundreds of thousands engineers, programmers and developers in a worldwide community of knowledge and expertise. Since its founding in 1960, Elektor has been dedicated...
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by Clemens Valens
Two New Arduino UNO R4 Boards: Minima and WiFi
The Arduino UNO R4 Minima and the Arduino UNO R4 WiFi have finally hit the shelves, introducing an exciting new chapter for Arduino enthusiasts and...