Arduino Coding Practices

Arduino Coding Practices

Application skill for Arduino library + sketch guides (archived awesome-guidelines capsules). For portable C++ outside Arduino core, load cpp-coding-practices. Professional embedded without Arduino APIs: follow project RTOS/SDK docs.

Core Principle

Arduino quality is beginner-first APIs and compile-ready packaging, camelCase high-level methods, hardware init in begin() not constructors, guarded .h/.cpp pairs, examples that build.

When to Use / NOT

• Arduino libraries (*.h/*.cpp), sketch .ino, library.properties, Library Manager prep.
• Reviewing public API names, Stream serial ports, Morse-style class layout.

NOT when:

• Generic C++ desktop/server code, cpp-coding-practices.
• Bare-metal non-Arduino SDK firmware with no Arduino core.
• Python MicroPython/CircuitPython, stack-specific docs.

Workflow

1. API, naming, read/write/begin, Stream, no pointer traps (arduino-style-library-api.md).
2. Structure, guards, ctor vs begin, _private fields (arduino-style-library-structure.md).
3. Sketches, setup/loop, camelCase, braces, AVR loop discipline (arduino-style-sketch-code.md).
4. Packaging, keywords, examples, properties, compile (arduino-style-packaging-verify.md).
5. Verify, arduino-cli compile on example; hardware smoke if available.

Red Flags

• pinMode or bus init inside constructor
• snake_case public library methods
• Public API requiring pointer args (&x, char*) from sketches
• Boolean parameters instead of two named methods
• Hard-coded Serial only (no Stream&)
• Missing #include "Arduino.h" or include guard in library header
• Wrong file extensions (.cpp.txt, library .ino source)
• Missing begin() when hardware setup required
• No examples/ sketch or example fails compile
• ALL_CAPS constant walls hurting readability
• Heavy String allocation in tight loop() on AVR
• Unbraced single-line if in maintained sketch code
• Publish without library.properties when targeting Library Manager

Verification

• arduino-cli compile on primary example with project FQBN
• Header review: guards, Arduino.h, public camelCase, private _fields
• Constructor vs begin() split check
• keywords.txt tab-separated spot check
• Optional: compare API to Adafruit high-level wrapper pattern (one call → one user value)

References

• awesome-guidelines/references/arduino-style-learning-note.md
• awesome-guidelines/references/arduino-style-library-api.md
• awesome-guidelines/references/arduino-style-library-structure.md
• awesome-guidelines/references/arduino-style-sketch-code.md
• awesome-guidelines/references/arduino-style-packaging-verify.md

Related skills

• cpp-coding-practices, portable C++ layout and ownership
• c-coding-practices, low-level C safety when mixing C drivers