Five outputs and a sequence
A pelican crossing on four pins, with a request button and an inverter chip that answers it faster than the sketch can. Where software ends and hardware starts.
Open it in the simulatorAll paths
Embedded on the Arduino Uno
One board, twenty pins and a C++ sketch. From a lamp you switch to a game you can play.
0 of 16 done
What you will build
6 projects, built step by step
16 lessons in 9 chapters, about 12 hours on a simulated Arduino Uno R3. Free, in your browser, every step checked by the simulator.
Press once for on, once for off
The difference between a level and an edge, a variable that remembers, and the debounce window that makes a mechanical switch usable.
Open it in the simulatorBlinking and listening at the same time
The payoff for non-blocking code: a board that keeps a rhythm and still answers a button in microseconds. Feel the difference by breaking it.
Open it in the simulatorDeciding from a reading
A lamp that fades up when the sensor says dark, and an indicator that does not. What a threshold is, why a ramp looks better than a jump, and where hysteresis comes in.
Open it in the simulatorTaking commands
The monitor is an input too. Read characters without blocking, act on them, and answer everything, including the things you do not understand.
Open it in the simulatorProject: a metronome
A click on a piezo, a lamp on the beat, and two buttons that change the tempo without missing one. Making a note out of a pin.
Open it in the simulatorThe map
Chapter by chapter
Each lesson opens when the one before it is done, and each chapter ends in a project.
Chapter 1
Driving things
Make a pin do something, then make several pins do something in order.
- Open135 XP
Blink: the first program
An Arduino Uno, one pin and a program. Drive an output from code, watch the timing be real, and find out what delay() costs you.
0 of 5 steps
- Locked160 XP
Two outputs, taking turns
A second lamp on a second pin. What pinMode actually does, why a pin is not an output until you say so, and what happens to the timing when you change one number.
0 of 6 steps
- ProjectLocked320 XP
Five outputs and a sequence
A pelican crossing on four pins, with a request button and an inverter chip that answers it faster than the sketch can. Where software ends and hardware starts.
0 of 6 steps
4 questions, graded as you go.
Chapter 2
Reading a button
Pull-ups, why pressed reads low, and the difference between a level and an edge.
- Locked160 XP
Reading a pin, and the pull-up
A button with no resistor of its own, an input that must never float, and why pressed reads low. The single most common wiring in embedded work.
0 of 6 steps
- ProjectLocked320 XP
Press once for on, once for off
The difference between a level and an edge, a variable that remembers, and the debounce window that makes a mechanical switch usable.
0 of 6 steps
5 questions, graded as you go.
Chapter 3
Timing without delay
Ask the time instead of waiting for it, and the board stops being deaf.
- Locked160 XP
Two rates at once, without delay
The pattern that unlocks everything else: keep when each thing last happened, and ask the time instead of waiting for it.
0 of 6 steps
- ProjectLocked320 XP
Blinking and listening at the same time
The payoff for non-blocking code: a board that keeps a rhythm and still answers a button in microseconds. Feel the difference by breaking it.
0 of 6 steps
4 questions, graded as you go.
Chapter 4
Reading a voltage
The ADC, a divider, and deciding something from a number that drifts.
- Locked160 XP
Reading a voltage
The ADC turns a voltage into a number from 0 to 1023. Build a divider, read two taps of it, and work out what a count is worth.
0 of 6 steps
- ProjectLocked320 XP
Deciding from a reading
A lamp that fades up when the sensor says dark, and an indicator that does not. What a threshold is, why a ramp looks better than a jump, and where hysteresis comes in.
0 of 6 steps
4 questions, graded as you go.
Chapter 5
PWM and brightness
One pin, any brightness, and the six pins on this board that can do it.
- Locked160 XP
Brightness from a digital pin
Eight duty cycles on pin 9 next to a pin that can only be on or off. What PWM is, which pins have it, and what it is not good for.
0 of 6 steps
4 questions, graded as you go.
Chapter 6
Serial in and out
The board talks, and then it listens.
- Locked160 XP
Making the board talk
Printing is how you find out what a board thinks. What Serial.begin does, what a baud rate really costs, and how to print a number without lying about it.
0 of 6 steps
- ProjectLocked320 XP
Taking commands
The monitor is an input too. Read characters without blocking, act on them, and answer everything, including the things you do not understand.
0 of 6 steps
4 questions, graded as you go.
Chapter 7
Interrupts
A handler that runs the moment a pin changes, and the rules that come with it.
- Locked160 XP
Reading a button, and printing what it says
A pull-up, a pin that reads low when the button is pressed, and a count printed to the serial monitor. Finish by catching the contacts bouncing.
0 of 6 steps
3 questions, graded as you go.
Chapter 8
Showing a number
Seven LEDs in the shape of an eight, and how to run out of pins.
- Locked145 XP
Showing a number
A seven segment display is seven LEDs in a pattern. Drive it from a table, roll a die on it, and find out why one resistor in the common return is a compromise.
0 of 6 steps
4 questions, graded as you go.
Chapter 9
Two small projects
Put all of it together twice, in something you would show somebody.
- Locked160 XP
Project: a reaction timer
A lamp at a random moment, a button, and the milliseconds in between. Randomness, measuring time, and catching a cheat.
0 of 6 steps
- ProjectLocked320 XP
Project: a metronome
A click on a piezo, a lamp on the beat, and two buttons that change the tempo without missing one. Making a note out of a pin.
0 of 6 steps
5 questions, graded as you go.
Syllabus
Every lesson in the course
All 16 lessons, in order, each with what it covers. Any of them opens in the editor right away.
Driving things
- Blink: the first programAn Arduino Uno, one pin and a program. Drive an output from code, watch the timing be real, and find out what delay() costs you.
- Two outputs, taking turnsA second lamp on a second pin. What pinMode actually does, why a pin is not an output until you say so, and what happens to the timing when you change one number.
- Five outputs and a sequenceA pelican crossing on four pins, with a request button and an inverter chip that answers it faster than the sketch can. Where software ends and hardware starts.
Reading a button
- Reading a pin, and the pull-upA button with no resistor of its own, an input that must never float, and why pressed reads low. The single most common wiring in embedded work.
- Press once for on, once for offThe difference between a level and an edge, a variable that remembers, and the debounce window that makes a mechanical switch usable.
Timing without delay
- Two rates at once, without delayThe pattern that unlocks everything else: keep when each thing last happened, and ask the time instead of waiting for it.
- Blinking and listening at the same timeThe payoff for non-blocking code: a board that keeps a rhythm and still answers a button in microseconds. Feel the difference by breaking it.
Reading a voltage
- Reading a voltageThe ADC turns a voltage into a number from 0 to 1023. Build a divider, read two taps of it, and work out what a count is worth.
- Deciding from a readingA lamp that fades up when the sensor says dark, and an indicator that does not. What a threshold is, why a ramp looks better than a jump, and where hysteresis comes in.
PWM and brightness
- Brightness from a digital pinEight duty cycles on pin 9 next to a pin that can only be on or off. What PWM is, which pins have it, and what it is not good for.
Serial in and out
- Making the board talkPrinting is how you find out what a board thinks. What Serial.begin does, what a baud rate really costs, and how to print a number without lying about it.
- Taking commandsThe monitor is an input too. Read characters without blocking, act on them, and answer everything, including the things you do not understand.
Interrupts
- Reading a button, and printing what it saysA pull-up, a pin that reads low when the button is pressed, and a count printed to the serial monitor. Finish by catching the contacts bouncing.
Showing a number
- Showing a numberA seven segment display is seven LEDs in a pattern. Drive it from a table, roll a die on it, and find out why one resistor in the common return is a compromise.
Two small projects
- Project: a reaction timerA lamp at a random moment, a button, and the milliseconds in between. Randomness, measuring time, and catching a cheat.
- Project: a metronomeA click on a piezo, a lamp on the beat, and two buttons that change the tempo without missing one. Making a note out of a pin.
Keep going
The next course on your track
Embedded on the Arduino Uno is part of the embedded track, a ladder of courses from zero to expert.
Interactive devices on the Uno
Read people and sensors without blocking, control an output, then finish with two playable builds.
Open the next courseEmbedded track
Arduino, ESP32, Raspberry Pi Pico and STM32: pins, timing, buses, motors, WiFi, registers and debugging, every lesson checked on a simulated board.
See every course on the trackKits
Build it on your bench too
Every lesson runs in the simulator with nothing to buy. When you want the real thing, these kits have the parts.
Find your kit
Pick the starter kit you own and run every lesson in its manual with the same parts on the same pins.
See every kitQuestions
About Embedded on the Arduino Uno
Is Embedded on the Arduino Uno free?
Yes. All 16 lessons of Embedded on the Arduino Uno are free and run in your browser, with nothing to install and no parts to buy before you start.
Do I need a real Arduino Uno R3?
No. Every lesson runs on a simulated Arduino Uno R3 with its parts on the canvas, and the simulator checks each step as you go. When you want to build it for real, the same wiring and code work on a real board.
How long does Embedded on the Arduino Uno take?
About 12 hours: 16 lessons in 9 chapters, each one a few short steps. Your progress is kept, so you can stop after any lesson and pick up where you left off.
What will I build?
Each chapter ends in a project that puts it together: Five outputs and a sequence, Press once for on, once for off, Blinking and listening at the same time, Deciding from a reading, Taking commands and Project: a metronome.
Where do I start?
With "Blink: the first program", and each lesson builds on the one before it. New to circuits? Electronics basics is the course that starts from zero.