Control System Hierarchy Overview - dtex/johnny-five GitHub Wiki

Control System

The Control System is the Board, which is the root of all projects. From the Board, any number of Components may be connected and controlled. Examples: Arduino UNO, Electric Imp, BeagleBone Black, etc.

Component

A Component is any sensor or effector. A Component is represented in a program by an instance of a class initialized with an appropriate Controller. A Component may also have a sub-classification in the form of a Device. Examples: LED, LCD, Servo, Temperature sensor

Controller

A Controller contains general or Component-specific programming commands that conform to a common interface.

Device

A Device is a type sub-classification of a Component. Motors are a good example: a motor can be "directional" or "non-directional".