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.
Easy and Affordable Digital Signal Processing
The aim of this book is to teach the basic principles of Digital Signal Processing (DSP) and to introduce it from a practical point of view using the bare minimum of mathematics. Only the basic level of discrete-time systems theory is given, sufficient to implement DSP applications in real time. The practical implementations are described in real time using the highly popular ESP32 DevKitC microcontroller development board. With the low cost and extremely popular ESP32 microcontroller, you should be able to design elementary DSP projects with sampling frequencies within the audio range. All programming is done using the popular Arduino IDE in conjunction with the C language compiler.
After laying a solid foundation of DSP theory and pertinent discussions on the main DSP software tools on the market, the book presents the following audio-based sound and DSP projects:
Using an I²S-based digital microphone to capture audio sound
Using an I²S-based class-D audio amplifier and speaker
Playing MP3 music stored on an SD card through an I²S-based amplifier and speaker
Playing MP3 music files stored in ESP32 flash memory through an I²S-based amplifier and speaker
Mono and stereo Internet radio with I²S-based amplifiers and speakers
Text-to-speech output with an I²S-based amplifier and speaker
Using the volume control in I²S-based amplifier and speaker systems
A speaking event counter with an I²S-based amplifier and speaker
An adjustable sinewave generator with I²S-based amplifier and speaker
Using the Pmod I²S2 24-bit fast ADC/DAC module
Digital low-pass and band-pass real-time FIR filter design with external and internal A/D and D/A conversion
Digital low-pass and band-pass real-time IIR filter design with external and internal A/D and D/A conversion
Fast Fourier Transforms (FFT)
The Elektor MultiCalculator Kit is an Arduino-based multifunction calculator that goes beyond basic calculations. It offers 22 functions including light and temperature measurement, differential temperature analysis, and NEC IR remote control decoding. The Elektor MultiCalculator is a handy tool for use in your projects or for educational purposes.
The kit features a Pro Mini module as the computing unit. The PCB is easy to assemble using through-hole components. The enclosure consists of 11 acrylic panels and mounting materials for easy assembly. Additionally, the device is equipped with a 16x2 alphanumeric LCD, 20 buttons, and temperature sensors.
The Elektor MultiCalculator is programmable with the Arduino IDE through a 6-way PCB header. The available software is bilingual (English and Dutch). The calculator can be programmed with a programming adapter, and it is powered through USB-C.
Modes of Operation
Calculator
4-Ring Resistor Code
5-Ring Resistor Code
Decimal to Hexadecimal and Character (ASCII) conversion
Hexadecimal to Decimal and Character (ASCII) conversion
Decimal to Binary and Character (ASCII) conversion
Binary to Decimal and Hexadecimal conversion
Hz, nF, capacitive reactance (XC) calculation
Hz, µH, inductive reactance (XL) calculation
Resistance calculation of two resistors connected in parallel
Resistance calculation of two resistors connected in series
Calculation of unknown parallel resistor
Temperature measurement
Differential temperature measurement T1&T2 and Delta (δ)
Light measurement
Stopwatch with lap time function
Item counter
NEC IR remote control decoding
AWG conversion (American Wire Gauge)
Rolling Dice
Personalize startup message
Temperature calibration
Specifications
Menu languages: English, Dutch
Dimensions: 92 x 138 x 40 mm
Build time: approx. 5 hours
Included
PCB and though-hole components
Precut acrylic sheets with all mechanical parts
Pro Mini microcontroller module (ATmega328/5 V/16 MHz)
Programming adapter
Waterproof temperature sensors
USB-C cable
Downloads
Software
The Arduino MKR Zero is a development board for music makers! With an SD card holder and dedicated SPI interfaces (SPI1), you are able to play music files without extra hardware.
The MKR Zero brings you the power of a Zero in the smaller format established by the MKR form factor. The MKR Zero board acts as a great educational tool for learning about 32-bit application development. It has an on-board SD connector with dedicated SPI interfaces (SPI1) that allows you to play with MUSIC files with no extra hardware! The board is powered by Atmel’s SAMD21 MCU, which features a 32-bit ARM Cortex M0+ core.
The board contains everything needed to support the microcontroller; simply connect it to a computer with a micro-USB cable or power it by a LiPo battery. The battery voltage can also be monitored since a connection between the battery and the analog converter of the board exists.
Specifications
Microcontroller
SAMD21 ARM Cortex-M0+ 32-bit low power
Board power supply (USB/VIN)
5 V
Supported battery
Li-Po single cell, 3.7 V, 700 mAh minimum
DC current for 3.3 V pin
600 mA
DC current for 5 V pin
600 mA
Circuit operating voltage
3.3 V
Digital I/O pins
22
PWM pins
12 (0, 1, 2, 3, 4, 5, 6, 7, 8, 10, A3 - or 18 -, A4 -or 19)
UART
1
SPI
1
I²C
1
Analog input pins
7 (ADC 8/10/12 bit)
Analog output pins
1 (DAC 10 bit)
External interrupts
10 (0, 1, 4, 5, 6, 7, 8, A1 -or 16-, A2 - or 17)
DC current per I/O pin
7 mA
Flash memory
256 KB
Flash memory for bootloader
8 KB
SRAM
32 KB
EEPROM
No
Clock speed
32.768 kHz (RTC), 48 MHz
LED_BUILTIN
32
Downloads
Datasheet
Eagle Files
Schematics
Fritzing
Pinout
ESP32-C3-DevKitM-1 is an entry-level development board based on ESP32-C3-MINI-1, a module named for its small size. This board integrates complete Wi-Fi and Bluetooth LE functions. Most of the I/O pins on the ESP32-C3-MINI-1 module are broken out to the pin headers on both sides of this board for easy interfacing. Developers can either connect peripherals with jumper wires or mount ESP32-C3-DevKitM-1 on a breadboard. Specifications ESP32-C3-MINI-1 ESP32-C3-MINI-1 is a general-purpose Wi-Fi and Bluetooth LE combo module that comes with a PCB antenna. At the core of this module is ESP32-C3FN4, a chip that has an embedded flash of 4 MB. Since flash is packaged in the ESP32-C3FN4 chip, rather than integrated into the module, ESP32-C3-MINI-1 has a smaller package size. 5 V to 3.3 V LDO Power regulator that converts a 5 V supply into a 3.3 V output. 5 V Power On LED Turns on when the USB power is connected to the board. Pin Headers All available GPIO pins (except for the SPI bus for flash) are broken out to the pin headers on the board. For details, please see Header Block. Boot Button Download button. Holding down Boot and then pressing Reset initiates Firmware Download mode for downloading firmware through the serial port. Micro-USB Port USB interface. Power supply for the board as well as the communication interface between a computer and the ESP32-C3FN4 chip. Reset Button Press this button to restart the system. USB-to-UART Bridge Single USB-UART bridge chip provides transfer rates up to 3 Mbps. RGB LED Addressable RGB LED, driven by GPIO 8. Downloads ESP32-C3 Datasheet ESP32-C3-MINI-1 Datasheet ESP32-C3-DevKitM-1 Schematic ESP32-C3-DevKitM-1 PCB Layout ESP32-C3-DevKitM-1 Dimensions
Arduino MKR NB 1500 allows you to build your next smart project.
Ever wanted an automated house? Or a smart garden? Well, now it’s easy with the Arduino IoT Cloud compatible boards. It means: you can connect devices, visualize data, control and share your projects from anywhere in the world. Whether you’re a beginner or a pro, we have a wide range of plans to make sure you get the features you need.
Add Narrowband communication to your project with the MKR NB 1500. It's the perfect choice for devices in remote locations without an Internet connection, or in situations in which power isn't available like on-field deployments, remote metering systems, solar-powered devices, or other extreme scenarios.
The board's main processor is a low power ARM Cortex-M0 32-bit SAMD21, like in the other boards within the Arduino MKR family. The Narrowband connectivity is performed with a module from u-blox, the SARA-R410M-02B, a low power chipset operating in the de different bands of the IoT LTE cellular range. On top of those, secure communication is ensured through the Microchip ECC508 crypto chip. Besides that, the pcb includes a battery charger, and a connector for an external antenna.
This board is designed for global use, providing connectivity on LTE's Cat M1/NB1 bands 1, 2, 3, 4, 5, 8, 12, 13, 18, 19, 20, 25, 26, 28. Operators offering service in that part of the spectrum include: Vodafone, AT&T, T-Mobile USA, Telstra, and Verizon, among others.
Specifications
The Arduino MKR NB 1500 is based on the SAMD21 microcontroller.
Microcontroller
SAMD21 Cortex-M0+ 32-bit low power ARM MCU (datasheet)
Radio module
u-blox SARA-R410M-02B (datasheet summary)
Secure element
ATECC508 (datasheet)
Board power supply (USB/VIN)
5 V
Supported battery
Li-Po Single Cell, 3.7 V, 1500 mAh Minimum
Circuit operating voltage
3.3 V
Digital I/O pins
8
PWM pins
13 (0 .. 8, 10, 12, 18 / A3, 19 / A4)
UART
1
SPI
1
I²C
1
Analog input pins
7 (ADC 8/10/12 bit)
Analog output pins
1 (DAC 10 bit)
External interrupts
8 (0, 1, 4, 5, 6, 7, 8, 16 / A1, 17 / A2)
DC current per I/O pin
7 mA
Flash memory
256 KB (internal)
SRAM
32 KB
EEPROM
No
Clock speed
32.768 kHz (RTC), 48 MHz
LED_BUILTIN
6
USB
Full-speed USB device and embedded host
Antenna gain
2 dB
Carrier frequency
LTE bands 1, 2, 3, 4, 5, 8, 12, 13, 18, 19, 20, 25, 26, 28
Power class (radio)
LTE Cat M1 / NB1: Class 3 (23 dBm)
Data rate (LTE M1 halp-duplex)
UL 375 kbps / DL 300 kbps
Data rate (LTE NB1 full-duplex)
UL 62.5 kbps / DL 27.2 kbps
Working region
Multiregion
Device location
GNSS via modem
Power consumption (LTE M1)
min 100 mA / max 190 mA
Power consumption (LTE NB1)
min 60 mA / max 140 mA
SIM card
MicroSIM (not included with the board)
Dimensions
67.6 x 25 mm
Weight
32 g
Downloads
Eagle Files
Schematics
Pinout
Over 40 Fully Tested ESP32 Projects Using Arduino IDE and the LVGL Graphics Library
This bundle includes the ESP32 Cheap Yellow Display (CYD) – a compact development board combining a standard ESP32 microcontroller with a 320x240 pixel TFT color display. The board also features multiple connectors for GPIO, serial communication (TX/RX), power, and ground. The built-in display is a major advantage, allowing users to create complex, graphics-based projects without the need for external LCDs or displays.
The accompanying book introduces the CYD board's hardware and on-board connectors in detail. It provides a range of beginner to intermediate-level projects developed using the popular Arduino IDE 2.0. Both basic graphics functions and the powerful LVGL graphics library are covered, with practical projects illustrating each approach.
All included projects have been fully tested and are ready to use. The book provides block diagrams, circuit schematics, complete code listings, and step-by-step explanations. With the LVGL library, readers can create modern, full-color graphical interfaces using widgets such as buttons, labels, sliders, calendars, keyboards, charts, tables, menus, animations, and more.
ESP32 Cheap Yellow Display Board
This development board (also known as "Cheap Yellow Display") is powered by the ESP-WROOM-32, a dual-core MCU with integrated Wi-Fi and Bluetooth capabilities. It operates at a main frequency of up to 240 MHz, with 520 KB SRAM, 448 KBROM, and a 4 MB Flash memory. The board features a 2.8-inch display with a resolution of 240x320 and resistive touch.
Furthermore, the board includes a backlight control circuit, touch control circuit, speaker drive circuit, photosensitive circuit, and RGB-LED control circuit. It also provides a TF card slot, serial interface, DHT11 temperature and humidity sensor interface, and additional IO ports.
The module supports development in Arduino IDE, ESP-IDE, MicroPython, and Mixly.
Applications
Image transmission for Smart Home device
Wireless monitoring
Smart agriculture
QR wireless recognition
Wireless positioning system signal
And other IoT applications
Specifications
Microcontroller
ESP-WROOM-32 (Dual-core MCU with integrated Wi-Fi and Bluetooth)
Frequency
Up to 240 MHz (computing power is up to 600 DMIPS)
SRAM
520 KB
ROM
448 KB
Flash
4 MB
Operating voltage
5 V
Power consumption
approx. 115 mA
Display
2.8-inch color TFT screen (240 x 320)
Touch
Resistive Touch
Driver chip
ILI9341
Dimensions
50 x 86 mm
Weight
50 g
Downloads
GitHub
Contents of the Bundle
The ESP32 Cheap Yellow Display Book (normal price: €35)
ESP32 Cheap Yellow Display Board (normal price: €25)
1x ESP32 Dev Board with 2.8" Display and acrylic Shell
1x Touch pen
1x Connector cable
1x USB cable
Are you tired of all the different Arduino boards, and having to choose which features you need? Wouldn't it be much simpler to have all the best features on the same board and not have to compromise? That is precisely what the people at SparkFun thought and delivered the fantastic SparkFun RedBoard Programmed with Arduino. Features ATmega328 microcontroller with Optiboot (UNO) Bootloader Input voltage: 7-15 V 0-5 V outputs with 3.3 V compatible inputs 6 Analog Inputs 14 Digital I/O Pins (6 PWM outputs) ISP Header 16 MHz Clock Spee 32 k Flash Memory R3 Shield Compatible All SMD Construction USB Programming Facilitated by the Ubiquitous FTDI FT231X Red PCB The SparkFun RedBoard combines the stability of the FTDI, the simplicity of the Uno's Optiboot bootloader, and the R3 shield compatibility of the Uno R3. RedBoard has the hardware peripherals you are used to: 6 Analog Inputs 14 Digital I/O pins (6 PWM pins) SPI UART External interrupts Downloads Drivers GitHub
ESP32-C3-WROOM-02U is a general-purpose Wi-Fi and Bluetooth LE module. The rich set of peripherals and high performance make the module an ideal choice for smart homes, industrial automation, health care, consumer electronics, etc.
ESP32-C3-WROOM-02U features an external SPI flash and comes with a connector for an external antenna.
ESP32-C3-WROOM-02U has an operating ambient temperature option of –40∼85°C, embedded with the ESP32-C3 chip. ESP32-C3 has a 32-bit RISC-V single-core processor. It integrates a rich set of peripherals, ranging from UART, I²C, I²S, remote control peripheral, LED PWM controller, general DMA controller, TWAI controller, USB Serial/JTAG controller, temperature sensor, ADC, etc. It also includes SPI, Dual SPI and Quad SPI interfaces.
Features
Flash: 4 MB (Quad SPI)
Dimensions: 18.0 x 20.0 x 3.2 mm
Downloads
Datasheet
This USB Stick contains more than 300 Arduino-related articles published in Elektor Magazine. The content includes both background articles and projects on the following topics:
Software & hardware development: Tutorials on Arduino software development using Arduino IDE, Atmel Studio, Shields, and essential programming concepts.
Learning: The Microcontroller Bootcamp offers a structured approach to programming embedded systems.
Data acquisition & measurement: Projects such as a 16-bit data logger, lathe tachometer, and an AC grid analyzer for capturing and analyzing real-time signals.
Wireless communication: Learn how to implement wireless networks, create an Android interface, and communicate effectively with microcontrollers.
Robotics and automation: This covers the Arduino Nano Robot Controller, supporting boards for automation, and explores various Arduino shields to enhance functionality.
Self-build projects: Unique projects such as laser projection, Numitron clock and thermometer, ELF receiver, Theremino, and touch LED interfaces highlight creative applications.
Whether you're a beginner or an experienced maker, this collection is a valuable resource for learning, experimenting, and pushing the boundaries of Arduino technology.
Easy and Affordable Digital Signal ProcessingThe aim of this book is to teach the basic principles of Digital Signal Processing (DSP) and to introduce it from a practical point of view using the bare minimum of mathematics. Only the basic level of discrete-time systems theory is given, sufficient to implement DSP applications in real time. The practical implementations are described in real time using the highly popular ESP32 DevKitC microcontroller development board. With the low cost and extremely popular ESP32 microcontroller, you should be able to design elementary DSP projects with sampling frequencies within the audio range. All programming is done using the popular Arduino IDE in conjunction with the C language compiler.After laying a solid foundation of DSP theory and pertinent discussions on the main DSP software tools on the market, the book presents the following audio-based sound and DSP projects:
Using an I²S-based digital microphone to capture audio sound
Using an I²S-based class-D audio amplifier and speaker
Playing MP3 music stored on an SD card through an I²S-based amplifier and speaker
Playing MP3 music files stored in ESP32 flash memory through an I²S-based amplifier and speaker
Mono and stereo Internet radio with I²S-based amplifiers and speakers
Text-to-speech output with an I²S-based amplifier and speaker
Using the volume control in I²S-based amplifier and speaker systems
A speaking event counter with an I²S-based amplifier and speaker
An adjustable sinewave generator with I²S-based amplifier and speaker
Using the Pmod I²S2 24-bit fast ADC/DAC module
Digital low-pass and band-pass real-time FIR filter design with external and internal A/D and D/A conversion
Digital low-pass and band-pass real-time IIR filter design with external and internal A/D and D/A conversion
Fast Fourier Transforms (FFT)
Introducing the Elecrow ESP32 Terminal, a revolutionary handheld device engineered to elevate your projects to new heights. Boasting a 3.5″ 480 × 320 TFT capacitive...