Multilingual DIY Kit (incl. 27 RGB LEDs + Raspberry Pi Pico)
Bring some engineering magic to your festive season with the Wordy LED Christmas Tree, a unique DIY electronics kit designed by Elektor. This beautifully engineered 3D Christmas tree combines eleven PCBs, a Raspberry Pi Pico, and 27 addressable RGB LEDs to illuminate Christmas greetings in seven languages: Danish, Dutch, English, French, German, Italian, and Spanish.
Unlike ordinary LED trees, each word inside the tree has its own light chamber, creating a refined, softly glowing display without sound or flicker. The LEDs are fully WS2812-compatible and driven via the popular Adafruit NeoPixel library, making custom animations and color effects easy to create.
Perfect for makers, tinkerers, and festive electronics fans, this kit offers both an enjoyable build and a striking, conversation-worthy decoration. The Wordy Christmas Tree is your perfect holiday maker project!
Features
Multilingual greetings (7 languages) milled into the front panel
3D construction from 11 interlocking PCBs
Powered by Raspberry Pi Pico
27 individually addressable RGB LEDs (pre-mounted)
Smooth fade-in and fade-out animations
Fully programmable using the Arduino IDE
A 5-V power supply (with micro-USB connector) capable of ≥1 A is recommended for maximum brightness (not included)
Dimensions (H x W x D): 130 x 115 x 75 mm
Included
All required PCBs with LEDs and other SMD parts mounted
Raspberry Pi Pico (to be soldered & programmed by the user)
3-way pin header (to be soldered by the user)
3-way pin socket (to be soldered by the user)
4x Self-adhesive dome bumpers
Project Page
Elektor Labs
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
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
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
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 connectors (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.
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)
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
This hardware kit is especially prepared for 'The Official ESP32 Book'. The kit contains all the components used in the projects in this book. With the help of this hardware kit it should be easy and fun to build the projects in the book.
Included
1x ESP32 DevKitC
8x LEDs (red)
1x LED (green)
2x Push-button
8x 330 ohm resistors
1x Buzzer
1x RGB LED
1x TMP36 temperature sensor chip
1x DHT11 temperature and humidity chip
1x MCP23017 (DIL 28 package)
1x LDR
1x BC108 (or any other PNP) transistor
1x 7 segment LED
1x Small Microphone Module
1x I²C LCD
1x SG90 servo
1x 4x4 Keypad
8x Female-Male jumpers
4x Male-Male jumpers
1x Small breadboard
Elektor GREEN and GOLD members can download their digital edition here.
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