Applications of the Internet of Things (IoT) have spread across an enormously large number of industry sectors. The development of the vertical applications in these sectors is unbalanced. It is very important to sort out those vertical applications and identify common underpinning technologies that can be used across the board, so that interconnecting, interrelating, and synergized grand integration and new creative, disruptive applications can be achieved.
One of the common characteristics of the Internet of Things is that objects in a IoT world have to be instrumented
Why we need IOT is a fundamental change in the way information is generated, from mostly manual input to massively machine-generated without human intervention.
To achieve such 5A (anything, anywhere, anytime, anyway, anyhow) and 3I (instrumented, interconnected, and intelligent) capabilities, some common, horizontal, general-purpose technologies, standards, and platforms, especially middleware platforms based on common data representations just like the three-tiered application server middleware, HTML language, and HTTP protocol in the Internet/web arena, have to be established to support various vertical applications cost effectively, and new applications can be added to the platform unlimitedly.
Four pillars of IOT
RFID - The internet of devices.Example,Radio wave, NFC,IC cards
WSN-The internet of transducers. Examples Wireless mess, Bluetooth,Networks, ZigBee
M2M - Machine to machine. Examples, Cellular, Fixed networks, WAN, GPRS
SCADA-The network of controllers. Example-Wired Field Buses, CanBus,BacNet