IoT is not just technology; it is the concept of a whole new world where physical things such as cars, homes, buildings, and other components of cities have the ability to connect to the internet and interact among themselves and with humans as well. In short, it is a smart and connected world.

IoT is a phenomenon that can only be described and not defined as it is an inclusive technology that has unlimited boundaries.

A physical device in an IoT ecosystem is also called a thing or smart thing. A thing can be any device with one or more of the following features:

• Sensors (temperature, humidity, motion detector)
• Communication (wired or wireless)
• Actuators (motor, relay, display)
• Controller or processor (for computations, running software)

A few examples of things are:

• Tags such as NFC, RFID, and QR code, which are computer-readable and used to identify objects
• Devices such as iBeacon, Arduino, and Raspberry Pi, which have built in controllers/processors and communication channels such as Bluetooth, Wi-Fi, Ethernet, and so on
• Machines such as cars, bikes, AC units, and washing machines that can work autonomously
• Infrastructure such as smart-connected factories, smart-connected buildings, and smart cities