Wireless Sensor Technologies and Applications

Abstract

Recent years have witnessed tremendous advances in the design and applications of wirelessly networked and embedded sensors. Wireless sensor nodes are typically low-cost, low-power, small devices equipped with limited sensing, data processing and wireless communication capabilities, as well as power supplies. They leverage the concept of wireless sensor networks (WSNs), in which a large (possibly huge) number of collaborative sensor nodes could be deployed. As an outcome of the convergence of micro-electro-mechanical systems (MEMS) technology, wireless communications, and digital electronics, WSNs represent a significant improvement over traditional sensors. In fact, the rapid evolution of WSN technology has accelerated the development and deployment of various novel types of wireless sensors, e.g., multimedia sensors. Fulfilling Moore’s law, wireless sensors are becoming smaller and cheaper, and at the same time more powerful and ubiquitous. [...

Wireless Sensor Networks: Toward Smarter Railway Stations

“…A communication unit links a wireless sensor node with other nodes, while a transceiver encompasses the functionality of both transmitter and receiver. The wireless transmission media may be radio frequency, optical (laser), or infrared [32]. In the railway industry, this technology allows to monitor infrastructure, structures, and machinery in real-time and then turns data into intelligence, which aids to identify faults and support the operations [33].…”

AH-MAC: Adaptive Hierarchical MAC Protocol for Low-Rate Wireless Sensor Network Applications

“…(1) procedure start scan() (2) best parent addr = 0XFFFF; min dfs = 255; scan timer = ON (3) wake after(0) ⊳ wakeup now (4) start scan timer(0, SCAN LENGTH) ⊳ scan timer starts now and will fire after SCAN LENGTH (5) end procedure (6) procedure recv beacon(src, dfs, accept) (7) if scan timer then (8) if (dfs < min dfs & accept) then ⊳ replace current parent (9) min dfs = dfs (10) b e s tparent addr = src (11) end if (12) if (my parent addr == best parent addr) then ⊳ restore synchronization with last parent (13) s t o pscan timer() (14) s c a ntimer = OFF (15) end if (16) end if (17) if scan timer then (18) return (19) end if (20) if (not associated) then (21) s leepafter(slot time) (22) wak eafter( frame ) (23) sen dassociate request packet() (24) else if (data available) then (25) s leepafter(slot time) (26) wak eafter(my slot * slot time) ⊳ wake up in my slot to start my frame (27) trysend data() (28) else (29) s leepafter(0) (30) wak eafter(my slot * slot time) (31) end if (32) end procedure (33) procedure scan handler() ⊳ called when scan timer is fired (34) if (best parent addr < 0XFFFF) then (35) m yparent addr = best parent addr (36) m ydfs = min dfs + 1 (37) sca ntimer = OFF (38) else (39) s leepafter(0) (40) s ta rtscan timer(random delay, SCAN LENGTH) (41) end if (42) return (43) end procedure Algorithm 1: Cluster head join algorithm.…”

Contemporary Developments in Wireless Sensor Networks

“…Low power circuit designing will further make nodes self sustainable. Reconfigurable Hardware [10] -Use of Field Programmable Gate Arrays (FPGAs) for hardware design reconfiguration and components library to get a new sensor node quickly is being explored. The entire software design will have to be component based to support fast nodes development for various applications.…”