We depend on our five senses of sight, smell, touch, hearing, and feeling to navigate in the physical world. Electronic sensors are also used in a similar fashion, to enable us accurately measure and record phenomena that are imperceptible to our five senses. Wireless sensor networks are autonomous distributed sensors that pass data coorperatively through the network to a main location. A wireless sensor network consists of nodes which are connected to sensors.
Basically a wireless sensor network enables remote monitoring/sensing in a way that allows a small or wide area to be monitored depending on the number of nodes deployed.
Applications of wireless sensor networks include health care monitoring, environmental monitoring and industrial monitoring. A classic example is the use of wireless sensor networks to monitor air pollution levels in urban centers to enable regulatory bodies take appropriate action. Wireless sensor networks also enable the internet of things.