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Whether you are just starting out or building on what you already know, each one is chapters of lessons, ending in a project you actually finish.

What do you want to build?

1 of 3

Have you built electronics or written code before?

Electronics basics

7 h

A breadboard and a few parts, with one Uno blink at the start and no processor after it. What current, voltage, time and logic really do.

6 chapters14 lessons

0 of 14 done

Embedded on the Arduino Uno

12 h

One board, twenty pins and a C++ sketch. From a lamp you switch to a game you can play.

Arduino Uno R39 chapters16 lessons

0 of 16 done

Embedded on the ESP32-C3

11 h

A 32 bit RISC-V board at 160 MHz. Its own peripherals, its own 3.3 V rules, and a console at the end of it.

ESP32-C3-DevKitM-17 chapters13 lessons

0 of 13 done

Embedded on the Raspberry Pi Pico

6 h

A dual core Cortex-M0+ at 125 MHz. PWM on every pin, a 64 bit clock, and pins that do not forgive 5 V.

Raspberry Pi Pico4 chapters7 lessons

0 of 7 done

Build your own fight stick

4 h

One button to a full leverless controller on a Pico: SOCD, eight buttons, lit buttons, an OLED and modes.

Raspberry Pi Pico2 chapters5 lessons

0 of 5 done

Embedded on the STM32F411

6 h

A Cortex-M4 at 84 MHz, where a pin is a port and a number and every peripheral starts with its clock switched off.

STM32F411 Black Pill3 chapters6 lessons

0 of 6 done

C++ on a board

10 h

The language, one idea per lesson, on a board that shows you what your code did.

Arduino Uno R35 chapters13 lessons

0 of 13 done

Digital logic and memory

4 h

Build logic from individual gates, then make a bit persist, count and move through a register.

2 chapters4 lessons

0 of 4 done

Interactive devices on the Uno

8 h

Read people and sensors without blocking, control an output, then finish with two playable builds.

Arduino Uno R34 chapters9 lessons

0 of 9 done

From gates to a computer

16 h

Start with one NAND gate, package every circuit you build into a chip, and use your chips to build the next one: an adder, memory, a CPU of your own, and a computer that runs your program.

6 chapters23 lessons

0 of 23 done

Build a claw machine

6 h

Build a real arcade claw machine piece by piece, from one stepper motor to coins, a clock, a win sensor, lights and sound.

Arduino Uno R33 chapters8 lessons

0 of 8 done

Build a vending machine

5 h

Build a real vending machine piece by piece: a keypad, a screen, coins and change, spirals, a drop sensor and service mode.

Arduino Uno R33 chapters6 lessons

0 of 6 done

Build a balance bot

2 h

Three lessons on a two-wheel self-balancing robot: read its tilt, see what the wheels do to it, and write the PID that stands it up.

Arduino Uno R32 chapters3 lessons

0 of 3 done

Build a Halloween prop

5 h

Five porch props on the Uno, from a fog trigger to a talking skull, each one a complete build with the safety notes that go with it.

Arduino Uno R33 chapters5 lessons

0 of 5 done

Build Christmas lights

4 h

Four holiday builds on the Uno, from a star on the tree to a light show synced to a song, each one ready to hang up.

Arduino Uno R32 chapters4 lessons

0 of 4 done

Build a handheld game console

6 h

Wire a color screen, buttons and sound to an ESP32-C3, one working step at a time, and finish with three games you can play.

ESP32-C3-DevKitM-13 chapters7 lessons

0 of 7 done

Starter kit companion: the project book

10 h

Follows the fifteen projects in the official Arduino Starter Kit book, in its order, each one running in your browser.

Arduino Uno R34 chapters15 lessons

0 of 15 done

Starter kit companion: the 24-lesson kit

14 h

Follows the lessons in the Elegoo Uno R3 Super Starter Kit tutorial, in its order, each one running in your browser.

Arduino Uno R35 chapters24 lessons

0 of 24 done

Starter kit companion: the 33-lesson kit

20 h

Follows the lessons in the Elegoo Uno R3 Most Complete Starter Kit tutorial, in its order, each one running in your browser.

Arduino Uno R36 chapters33 lessons

0 of 33 done

Build a pocket pet

4 h

A Tamagotchi-style pet on an OLED: a screen, buttons, stats, a clock and a memory, ending with Pip.

Arduino Uno R33 chapters6 lessons

0 of 6 done

Build a desk buddy robot

4 h

Animated eyes on a round display that blink, feel, react to touch, tilt and light, ending with a robot that misses you.

ESP32-C3-DevKitM-13 chapters6 lessons

0 of 6 done

Model rocket flight computer

4 h

Bring up a barometer and an IMU, catch apogee, then fly a full state machine that logs to microSD.

Arduino Uno R32 chapters4 lessons

0 of 4 done

Mars rover

4 h

Drive by counting wheel slots, see hazards, do the science, then send your rover on a full mission.

Arduino Uno R32 chapters4 lessons

0 of 4 done

Satellite tracker

4 h

Aim a dish with a stepper and a servo, predict a pass from an orbit model, then track it across the sky.

Arduino Uno R32 chapters4 lessons

0 of 4 done

Build a spaceship control panel

5 h

Arming switches, a mission display, a countdown, an engine and a master alarm, then fly the whole panel to orbit.

Arduino Mega 25604 chapters7 lessons

0 of 7 done

Build an escape-room puzzle box

4 h

A keypad, a magnet key, an RFID card, a tilt sequence and a light puzzle, each one a lesson, then the whole box with its lock.

Arduino Mega 25603 chapters7 lessons

0 of 7 done

Build a pinball table

5 h

From two flipper buttons to a full table with a kicker, lights, sound and a saved high score, on a Mega.

Arduino Mega 25603 chapters5 lessons

0 of 5 done

Build a slot machine

4 h

Pull a real arcade lever, spin three OLED reels and pay out by a table whose odds you can check, on an Uno.

Arduino Uno R32 chapters4 lessons

0 of 4 done

Build a laser sword

3 h

A light saber style sword in three builds: a blade that ignites, motion you can hear, then the whole hilt with a sound font.

Arduino Uno R31 chapter3 lessons

0 of 3 done

Build an arc reactor and helmet

3 h

An arc reactor style chest light and a moving faceplate in three builds: the glow, the helmet, then the whole suit.

Arduino Uno R31 chapter3 lessons

0 of 3 done

Build a rhythm game

3 h

A rhythm game in three builds: notes that fall in time, buttons that judge your timing, then the whole game with combos and a high score.

Arduino Uno R31 chapter3 lessons

0 of 3 done

Build a 4x4x4 LED cube

3 h

Sixty-four LEDs from twenty wires in three builds: a shift register, multiplexing slowed down, then a cube full of animations.

Arduino Uno R31 chapter3 lessons

0 of 3 done

Build lights for the holidays

3 h

Four builds on the Uno for New Year’s Eve, Valentine’s Day, Diwali and Hanukkah, each one ready to put in a window.

Arduino Uno R32 chapters4 lessons

0 of 4 done

Sim racing and flight sim controllers

5 h

Template a button box, a shifter with a handbrake and a flight panel on a Pro Micro before you buy the parts.

SparkFun Pro Micro2 chapters4 lessons

0 of 4 done

Custom keyboards from the matrix up

3 h

Scan a key matrix, see ghosting and the diode that stops it, then add layers, a knob and per-key light.

SparkFun Pro Micro2 chapters3 lessons

0 of 3 done

Home Assistant devices

5 h

Build the sensors and switches people put around the house on an ESP32-C3, and see how each reading reaches Home Assistant.

ESP32-C3-DevKitM-13 chapters5 lessons

0 of 5 done

Model railroad electronics

4 h

Throw turnouts, run a level crossing, follow a train with block signals and drive a DC loco with momentum, all from an Uno.

Arduino Uno R32 chapters4 lessons

0 of 4 done

3D printer and CNC basics

4 h

Learn what a printer’s firmware does underneath: homing, temperature control with safety, G-code motion and runout detection.

Arduino Uno R32 chapters4 lessons

0 of 4 done

Build a macro pad

2 h

Twelve keys, a volume knob, three layers and a screen on a Pro Micro that plugs in as a keyboard.

SparkFun Pro Micro2 chapters3 lessons

0 of 3 done

Build a MIDI controller

2 h

Faders, drum pads, a knob and an encoder on a Pro Micro, sending real MIDI bytes you can read.

SparkFun Pro Micro2 chapters3 lessons

0 of 3 done

Build a smart home hub

3 h

A web dashboard on an ESP32-C3 that switches relays, reads sensors and runs schedules from a clock.

ESP32-C3-DevKitM-12 chapters3 lessons

0 of 3 done

Build a solar tracker

2 h

Light sensors and servos aim a panel, an INA219 measures it, and a fair experiment compares tracked with fixed.

Arduino Uno R32 chapters3 lessons

0 of 3 done

Build a science fair lie detector

2 h

Skin response and heart rate against a calm baseline: a science demo of the stress response, not a real lie detector.

Arduino Uno R32 chapters3 lessons

0 of 3 done

Build a guitar controller

1 h

A rhythm game guitar on a Pro Micro in three short lessons: frets and a strum bar that never double-strums, a whammy and star power, and your own config.

SparkFun Pro Micro2 chapters3 lessons

0 of 3 done

Build load cell pedals

1 h

Sim racing pedals on a Pro Micro in three short lessons: a load cell brake on an HX711, a hall throttle and a pot clutch, and the curve that makes it feel right.

SparkFun Pro Micro2 chapters3 lessons

0 of 3 done

Build a camera slider

1 h

A motorized camera slider on a Nano in three short lessons: homing a stepper, an eased video move, and a timelapse that settles before every shot.

Arduino Nano2 chapters3 lessons

0 of 3 done

The twelve week course

24 h

The classroom course, week by week: a loop on a breadboard through to a board talking over serial.

3 chapters12 lessons

0 of 12 done

This week

Experience earned since Monday, by the people who checked the box.

The weekly board needs an account.

Make an account

Badges

First light

Light an LED. Wire one up, press Run and watch it come on.

Not yet

Compiled in the browser

Compile your own code. Press Run on a board with a sketch in the editor.

Not yet

555 astable

Get a 555 running. Its output has to go high and low on its own.

Not yet

Found the fault

Fail a Check, work out why, and pass it.

Not yet

Every board

Run the Uno, the ESP32-C3, the Pico and the STM32 at least once each.

Not yet

Lesson published

Write a lesson in the editor and publish it.

Not yet

In a class

Join a class with the code your teacher gives you.

Not yet

Seven days

Pass a step on seven days in a row.

Not yet

Achievements

First wire

Drag from one pin to another.

Not yet

First Run

Press Run.

Not yet

Ten parts

Build something with ten parts in it.

Not yet

Four families

Place the Uno, the ESP32-C3, the Pico and the STM32.

Not yet

Night owl

Run something between midnight and four in the morning.

Not yet

Early bird

Run something between four and seven in the morning.

Not yet

It spoke

Get a board to print something.

Not yet

Long run

Leave a simulation going for a minute of its own time.

Not yet

Read the basics

Here to meet you wherever you are: the longer tutorials and the roundups each also come as a one-page PDF lesson plan you can download and hand to a class.

Tutorials and explainers

Connect a Board to WiFi and Serve a PageHow to Use a Breadboard: Your First CircuitOhm's Law, in a Circuit You Can RunPicking a Resistor for an LEDPull-Up Resistors and the Floating Input They FixDebouncing a Button: Why It Fires More Than OncePWM: Faking an Analog Voltage on a Digital PinThe 555 Astable: Timed by a Capacitor, Not a CrystalLogic Gates, and the Truth Table You Can PressShifting a Byte In, One Edge at a TimeBlink an LED with Arduino: Wiring and the ResistorArduino Button Debounce: See the Bounce, Then Fix ItArduino Blink Without Delay: Two LEDs, Two RatesArduino PWM Fade: analogWrite, Pins and the CurveBlink an LED on the ESP32-C3, Step by StepBlink an LED with a 555 Timer, No MicrocontrollerArduino Simulators Compared: An Honest RoundupHow to Simulate an Arduino Project Without HardwareMeasure It: Read a Circuit With a Scope and PlotterUART Serial Explained: Baud, Frames and the WireI2C Explained: Addresses, Pull-Ups and a ScannerSPI Explained: Clock, Data and Chip SelectInterrupts vs Polling on Arduino, Side by SideArduino State Machine: A Four-State Reaction GameESP32 HTTP GET Request: Fetch the Weather as JSONESP32 analogRead: 12 Bits, Attenuation and ADC2Raspberry Pi Pico PWM: Slices, Channels and 1 kHzSTM32 Blue Pill Blink with Registers, Not pinModeArduino Uno vs ESP32 vs Pico: Which to Learn First?Multisim Live Is Gone: A Chromebook AlternativeDigital Electronics on Chromebooks: Labs by UnitHalf Adder and Full Adder: Truth Table to BreadboardFlip-Flops Explained: SR Latch, D and JK Flip-FlopsScience Olympiad Circuit Lab Study Guide, B and CCircuit Lab Practice Test: 30 Measured QuestionsHow to Use a Multimeter: Practice on a Virtual OneArduino Science Fair Projects With a Real HypothesisReaction Time Science Fair Project With an ArduinoEngineering Science Fair Project: How to Write It Up555 Timer Projects for a Science Fair (No Coding)Circuit Lab Division B: Middle School Starter GuideSkillsUSA Electronics Technology Practice CircuitsTSA Electrical Applications: Practice CircuitsArduino Simulator for Chromebook, Free in ChromeFree Circuit Simulator for High School ClassesArduino Projects for Beginners, Each One RunningOnline SPICE Simulator: Run and Export NetlistsArduino LED Not Lighting Up or Dim: What to CheckArduino Compile Errors Explained, With the FixesHow to Debug Arduino Code: Prints to BreakpointsResistor Color Code Calculator and ChartArduino Relay Module: Active LOW and Startup ClicksHow Many LEDs Can One Arduino Pin Drive?Arduino I2C LCD Not Working: Blank, Blocks, No TextDIY Fight Stick on an Arduino Pro MicroLeverless Controller Build: Buttons, Pins and CodeSOCD Cleaning Explained, With CodeArcade Button Wiring for a Pro Micro or PicoDesign Your Own Fight Stick or Leverless ControllerDesign Your Sim Racing Button Box in the BrowserPrototype Your Keyboard Matrix Before You SolderHome Assistant and ESPHome Devices on an ESP32Arduino Model Railroad: Turnouts, Crossings, Signals3D Printer Firmware: Homing, PID, G-code, RunoutDIY Rhythm Game Controller: Guitar and Dance PadDIY Load Cell Pedals and Flight Stick on a Pro MicroDIY Stream Deck and Camera Slider With ArduinoArduino Eurorack CV Quantizer With a PWM DACOhm's Law Calculator: Volts, Amps, Ohms and WattsBuild a Computer From NAND Gates, Step by StepFollow Your Arduino Starter Kit in the BrowserDigital Logic Lab Experiments, Graded in the BrowserMicrocontroller Lab Experiments With No KitsElectrical Circuits Lab Online, With Graded ChecksVirtual Electronics Lab for College ClassesFree Arduino Simulator for Students, in the BrowserMicrocontroller Lab Viva Questions, With AnswersElectronics Lab Report Template, With an ExampleArduino Practical Exam Practice: Ten Timed TasksESP32 IoT Projects for Final Year StudentsArduino Mini Projects for Engineering StudentsArduino Temperature Data Logger Lab, Step by StepRun an Electronics Lab for Online ClassesArduino Simulator: Serial Monitor and Logic AnalyzerArduino Halloween Props to Build in Your BrowserArduino Christmas Lights to Build in Your BrowserArduino Holiday Projects for Every CelebrationSimulate Two Arduinos Talking Over SerialSimulate an ESP32 and an Arduino Uno TogetherArduino SPI Master and Slave, SimulatedVoltage Divider Simulator With a Real MeterRC Filter Simulator With a Bode PlotNPN Transistor Switch SimulatorOp-Amp Amplifier Simulator, Gain of 10LED I-V Curve, Simulated and Swept555 Timer Simulator: an LED Blinker

Electronics fundamentals, each with a circuit to poke

Project tutorials

The Arduino projects everybody builds, from a traffic light to an ultrasonic sensor, each one running at the top of its page with the wiring, the code and the common mistakes.

Arduino Traffic Light with a Crossing ButtonIntermediateArduino Servo Motor with a PotentiometerBeginnerArduino Ultrasonic Sensor (HC-SR04) TutorialIntermediateArduino I2C LCD 16x2: Wiring and CodeIntermediateArduino DHT22 Temperature and Humidity SensorIntermediateArduino 4x4 Keypad Code Lock with a RelayAdvancedArduino 7 Segment Display: an Electronic DieIntermediateArduino Stepper Motor: 28BYJ-48 and ULN2003IntermediateArduino OLED Display (SSD1306) TutorialIntermediateArduino MPU6050: Accelerometer and TiltIntermediateArduino Potentiometer: analogRead and a DimmerBeginnerArduino LDR Night Light (Photoresistor)BeginnerArduino IR Remote: Decode NEC, Switch LampsIntermediateESP32 NeoPixel (WS2812B) Rainbow TutorialIntermediateArduino Joystick Module: Wiring, Code, Live DemoIntermediateArduino TMP36 Temperature Sensor in °F and °CIntermediateArduino L293D Motor Driver: Forward and ReverseIntermediateArduino Buzzer and Piezo: Beeps, Notes, MetronomeBeginnerArduino MAX7219 8x8 LED Matrix: Wiring and CodeIntermediateArduino DS3231 Clock With a TM1637 DisplayIntermediatePIR Motion Sensor: How It Works, With an ArduinoBeginnerArduino RC522 RFID Reader: Wiring and CodeIntermediateArduino HX711 Load Cell: Calibration and CodeIntermediateArduino Soil Moisture Sensor: Code and WiringIntermediateArduino DS18B20 Temperature Sensor: Wiring and CodeIntermediateArduino L298N Motor Driver: Wiring, Jumpers and CodeIntermediateArduino A4988 and NEMA 17 Stepper: Wiring and CodeIntermediateArduino Sound Sensor (KY-038): Clap SwitchBeginnerArduino Obstacle Avoiding Robot: Code and WiringIntermediateArduino 4 Digit 7 Segment Display: Wiring and CodeAdvancedArduino nRF24L01: Wiring, Code and a Radio DoorbellAdvancedArduino PCA9685 Servo Driver: Wiring and CodeAdvancedArduino ILI9341 TFT Display: Wiring and CodeAdvancedArduino SD Card Module: A GPS Data LoggerAdvancedArduino HC-05 Bluetooth: Wiring, Code, AT CommandsBeginnerArduino NEO-6M GPS: Wiring, TinyGPS++ and CodeBeginnerArduino RGB LED: Wiring and Color Mixing CodeBeginnerArduino Rotary Encoder (KY-040): Wiring and CodeBeginnerESP32 Servo Motor: Wiring and LEDC CodeBeginnerRaspberry Pi Pico Button: Wiring and CodeBeginner

How it works

When does a day end?

At midnight UTC, the same moment for everybody.

What breaks a streak?

A day with no step passed. One missed day is covered if you hold a freeze.

How do I get a freeze?

Seven days in a row earns one, at most one a week.

What is a boss?

The last lesson of a chapter. It opens when the rest of the chapter is done and pays twice.

Where is my progress kept?

In this browser, and on your account as well when you have one. Signing in keeps the higher of the two.

Who sees the leaderboard?

Anyone can see the all-time board at /leaderboard, and only people who check the box are on it. It shows a name, level and XP, never an email. Students in a class are not listed there.

Keep your progress

Your streak, your XP and your badges stay with a free account, on any computer.