# Arduino Coding Practices

> Use when authoring or reviewing Arduino libraries/sketches, camelCase read/write/begin API,.h/.cpp structure, setup/loop lifecycle, Stream-aware serial, keywords/examples, and arduino-cli compile verify.

- Skill: `ryan-brosas/arduino-coding-practices` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ryan-brosas/arduino-coding-practices`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ryan-brosas/arduino-coding-practices/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: ryan-brosas (https://skillmd.com/u/ryan-brosas)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/ryan-brosas/arduino-coding-practices

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# 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