Components

Arduino boards by themselves generally offer only processing capabilities. A complete Physical Computing or IoT solution needs to capture environmental or human inputs, needs to display the processed output, and needs to take action based on the input data and processing.

All these capabilities are provided by additional circuits known as components.

Components can be broadly categorized into four types:

• Sensors, to collect data from the physical world.
• Relays and Actuators, to enable some action in the physical world
• Input Devices, to capture human inputs to complement sensor inputs, and
• Output Devices, to display processed data to humans.