Style Guide

This is just a proposal so far

Naming conventions

functions, methods and variables: lowercase_with_underscores
enums, structs and typedefs: _t suffix
enum members, #define members: ALLCAPS_WITH_UNDERSCORES
classes: CamelCase
properties: dromedaryCase

Whitespace

indent with 4 spaces
namespaces are not indented
public: and protected: inside a class are indented 1 space
single space around operators
single newline between function definitions
no spaces directly inside parenteses, single space outside of them
no trailing whitespace

Nesting

opening accolade on same line as function definition / control statement
closing accolade on its own line except in case of an else statement

Comments

copyright string at top of each file: Copyright 2015 Stichting Humanity4all
comment goes before code, not after it
strive to avoid inline comments
prefer /* */ style over //

Other formatting

line length of 80
use a header guard in header files -> SRC_FILENAME_H_ if file is in the src directory.

Design decisions

separate hardware interface and application logic as much as possible
write unit tests for your code where possible
no memory allocation outside of the setup function