Types and sizes
Every variable is a box with a fixed number of bytes. sizeof on the Uno, the fixed-width types from stdint.h, what each one holds, and a char that is really a number.
Open it in the simulatorAll paths
C from zero
The language under every microcontroller, from a first hello over serial: types and sizes, overflow, if and switch, loops, functions and pointers, arrays and strings. Ends with a serial quiz you build and make your own.
0 of 8 done
What you will build
4 projects, built step by step
8 lessons in 4 chapters, about 7 hours on a simulated Arduino Uno R3. Free, in your browser, every step checked by the simulator.
if and switch
The program picks one way to go: serial commands chosen with a switch, a fall-through bug to find and fix, an else-if ladder for temperatures, and a button read with if.
Open it in the simulatorFunctions
Name a piece of work once: prototypes, parameters and return values, why a copy cannot change the caller and a pointer can, a local that hides a global, and a static counter that remembers.
Open it in the simulatorProject: a serial quiz
Everything in the course in one program: questions in an array of structs, answers read from Serial, a switch to check them, a score, lamps for right and wrong, and a button to start again. Then make it yours.
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
Talk and count
Print over serial, and the boxes numbers live in.
- Open215 XP
Hello over serial
The first C program on an Uno: setup and loop, print against println, a char that turns out to be a number, and a line built with snprintf every second.
0 of 7 steps
- ProjectLocked380 XP
Types and sizes
Every variable is a box with a fixed number of bytes. sizeof on the Uno, the fixed-width types from stdint.h, what each one holds, and a char that is really a number.
0 of 6 steps
Chapter 2
Do the math, pick a path
Operators and what overflow does, then if and switch.
- Locked215 XP
Operators and overflow
Integer division and the remainder, a uint8_t that wraps like an odometer, an int that overflows and why that is undefined, the fix with a wider type, and bitwise operators on three lamps.
0 of 7 steps
- ProjectLocked480 XP
if and switch
The program picks one way to go: serial commands chosen with a switch, a fall-through bug to find and fix, an else-if ladder for temperatures, and a button read with if.
0 of 8 steps
Chapter 3
Again, and by name
Loops, then functions, pointers and scope.
- Locked215 XP
Loops
Do it again: for when you know how many times, while when you wait for something, do-while that always runs once, continue and break, a loop inside a loop, and a while that waits for a button.
0 of 7 steps
- ProjectLocked430 XP
Functions
Name a piece of work once: prototypes, parameters and return values, why a copy cannot change the caller and a pointer can, a local that hides a global, and a static counter that remembers.
0 of 7 steps
Chapter 4
Data and a project
Arrays and C strings, then a quiz built from everything.
- Locked215 XP
Arrays and strings
Many values in a row: sum and max over an array, its length from sizeof, and text as a char array ending in a zero byte, with strlen and strcmp written by hand and a buffer that never overflows.
0 of 7 steps
- ProjectLocked450 XP
Project: a serial quiz
Everything in the course in one program: questions in an array of structs, answers read from Serial, a switch to check them, a score, lamps for right and wrong, and a button to start again. Then make it yours.
0 of 8 steps
Syllabus
Every lesson in the course
All 8 lessons, in order, each with what it covers. Any of them opens in the editor right away.
Talk and count
- Hello over serialThe first C program on an Uno: setup and loop, print against println, a char that turns out to be a number, and a line built with snprintf every second.
- Types and sizesEvery variable is a box with a fixed number of bytes. sizeof on the Uno, the fixed-width types from stdint.h, what each one holds, and a char that is really a number.
Do the math, pick a path
- Operators and overflowInteger division and the remainder, a uint8_t that wraps like an odometer, an int that overflows and why that is undefined, the fix with a wider type, and bitwise operators on three lamps.
- if and switchThe program picks one way to go: serial commands chosen with a switch, a fall-through bug to find and fix, an else-if ladder for temperatures, and a button read with if.
Again, and by name
- LoopsDo it again: for when you know how many times, while when you wait for something, do-while that always runs once, continue and break, a loop inside a loop, and a while that waits for a button.
- FunctionsName a piece of work once: prototypes, parameters and return values, why a copy cannot change the caller and a pointer can, a local that hides a global, and a static counter that remembers.
Data and a project
- Arrays and stringsMany values in a row: sum and max over an array, its length from sizeof, and text as a char array ending in a zero byte, with strlen and strcmp written by hand and a buffer that never overflows.
- Project: a serial quizEverything in the course in one program: questions in an array of structs, answers read from Serial, a switch to check them, a score, lamps for right and wrong, and a button to start again. Then make it yours.
Kits
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 C from zero
Is C from zero free?
Yes. All 8 lessons of C from zero 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 C from zero take?
About 7 hours: 8 lessons in 4 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: Types and sizes, if and switch, Functions and Project: a serial quiz.
Where do I start?
With "Hello over serial", and each lesson builds on the one before it. New to circuits? Electronics basics is the course that starts from zero.