The building blocks of ASNs are sensors, which are compact, highly-accurate, power-efficient, and reliable electrical devices. Sensors detect and respond to inputs from the physical environment. Devices, incorporated with embedded software and electronics, in the network collect or “sense” data using sensing modules, data is then transferred via communication modules to a central processing unit for processing and analysis, which either results in an action being executed or information being disseminated.
Sensors convert these inputs (temperature, blood pressure, humidity, speed, etc.) to signals which can be measured electrically. The signals can either be displayed at the sensor location itself or transmitted to a central location for further processing. Sensors communicating with each other via wireless links form a wireless sensor network (WSN). A WSN can consist of hundreds to thousands of sensor nodes. The sensor node includes the sensor, a radio transceiver, an interfacing electronic circuit, and an energy source such as a re-chargeable battery. These nodes are multifunctional with computing and processing capabilities. Incorporating radio frequency identification (RFID) with the sensor nodes can further optimize these networks for object tracking and identification based applications. RFID technology uses radio waves to transmit a unique object identifier from an RFID tag to an RFID reader.
The integration of these WSNs with people, data and applications and incorporating technologies such as wireless networks, mobile networks and Internet technologies, result in an intelligent, interactive, environment able to monitor itself and take proactive steps without human intervention. Such an integration is better known as the Internet of Things (IoT). IoT envisages an advanced inter-connectivity of devices, systems and services via the Internet, covering various protocols, domains and applications. It is based on the premise that all devices (people, machines, etc.) are connected always, anywhere.
The multidisciplinary application areas of ASNs include, but are not limited to:
- transportation (vehicle and asset tracking, traffic monitoring, flow and congestion control, smart parking),
- healthcare (e-health, long-term surveillance of critically ill patients or elderly persons, early detection warning of medical conditions, management of chronic medical conditions),
- environmental (forest fire detection and prevention, air pollution monitoring, earth quake detection and early warning systems)
- agriculture (crop and fruit monitoring, precision agriculture: distributing fertilizers, pesticides, irrigation as needed, weed detection)
- water management (waste water treatment, water quality monitoring, water leakage detection)
- mining (monitoring of vibration on mining equipment, mine safety monitoring)
- animal sciences (tracking of wildlife, monitoring of migration patterns, detecting behavioral patterns, animal health,)
- smart homes and cities (energy saving smart grids, HVAC, light and temperature control)
- industrial (preventative maintenance and machine surveillance)
ASNs have a vast and diverse application potential, which can enhance safety and security, generates new knowledge, improves productivity, improves the quality of food, water, etc. The challenge lies in realizing the full potential of ASNs due to their resource-constrained characteristics, challenging operating environments, the scale of the networks and the inter-dependent multi-disciplinary nature of the solutions required for practical and widespread adoption common to complex systems.