Arch Rock unveiled a series of outdoor-ready, IP-based wireless sensor network devices developed to resist dust, water, corrosion and other elements commonly found in harsh environments. Dubbed PhyNet N4X, the system consists of wireless, battery-powered nodes supported by software that sends data to a Web-based database, said Roland Acra, the CEO of the San Francisco-based company.

“The system is used for remote monitoring and control applications,” Acra said. “It now can be put into fields, streets, municipal settings, landfill sites and a variety of places where the need to monitor systems is critical and systems need to withstand weather, dust, sleet and extreme temperature environments.”

According to Acra, the sensor nodes provide 12-bit precision analog and binary input ports to integrate with other third-party sensors used for environmental monitoring. Specifically, he said devices such as resistance temperature detectors, pressure sensors, thermistors and anemometers are supported by the system. In addition, the nodes can be connected to digital sensors, serial wired-bus systems and data loggers to capture, store and analyze data via an RS-232 serial port.

The system is compliant with IEEE 802.15.4, which governs devices designed to run on reduced power. It operates on the 2.5 GHz frequency band and performs as a mesh network, Acra said. A distributed scheme lets every node in the mesh relay data to the next node and then finally to a centralized database, he said, adding that the nodes also can be placed to act as multihop repeaters where necessary to traverse obstacles or extend range.

The system uses the PhyNet N4X series router, which aggregates and interconnects between dual IEEE 802.15.4 and IEEE 802.11b/g Wi-Fi radios (or IEEE 802.3 Ethernet links). A server stores sensor data that users access via a Web-based console or via standard Web services that allow customers to set up, manage and gather data from their sensor networks. The sensors are encased in NEMA 4X/IP 66 ruggedized enclosures for those parts of the PhyNet architecture exposed to harsh environments.

Public utilities specifically use the system to monitor the electrical grid for “visibility and pinpointing failures on the grid,” Acra said. “It can detect where fuses have blown and also can be used in remote metering applications to streamline the data flow to the utilities' command and control centers.”

According to Harry Forbes, senior analyst at the ARC Advisory Group, the fact that the system uses IP-based sensors to gather and transmit data makes it unique; it also makes it more power-efficient.

“If you have a network that consists largely of battery-powered devices and you need to have those last a long time, the PhyNet beats other networks when it comes to reliability and power efficiency.”

Each sensor node is equipped with an external battery pack that can be replaced in harsh environments without disturbing the sensitive node electronics, Acra said.

PhyNet N4X is available now. Products in NEMA 4X/IP 66 enclosures include a router, priced at $1995; IPserial node, $395; IPsensor node, $395; IPrelay node, $295; and N4X power pack, $100. A high-gain antenna kit for the router is priced separately at $295, according to the company. The server is priced at $3495.