[Wireless Japan] Hitachi Plant Develops Sensor Network Device Based on WLAN

Jul 23, 2008 18:47 Hiroki Yomogita, Nikkei Electronics

Hitachi Plant Technologies Ltd developed a wireless LAN-based sensor network device intended to be used for the traceability management of food and other products as well as the energy management in buildings and plants.

The company exhibited the device at Wireless Japan 2008, which opened on July 22, 2008. It integrates various kinds of sensors and the wireless LAN transceiver function.

The new device, which is provided in the form of a compact tag incorporating a wireless LAN transceiver IC and a sensor, is named "ZigNET-TAGMO." The ZigNET-TAGMO can transmit data measured by the sensors to the server via wireless LAN or the Internet.

Construction of a wireless network dedicated to this device is unnecessary because the device can use the existing hotspots, etc for wireless LAN. Thus, Hitachi Plant Technologies expects that the system using the latest device will be widespread faster than the existing wireless sensor networks based on ZigBee, etc.

Low power consumption enables monitoring of mobile objects

When the ZigNET-TAGMO is installed on the target object, information on the environment during the transportation, etc, of the object, such as the temperature and the humidity, can be measured and transmitted via wireless LAN. If no wireless LAN access point is available around the object, the obtained information is stored in the built-in memory.

When the object enters the area covered by a wireless LAN access point again, the accumulated data are transmitted at once. The device can also issue an alarm signal if the value measured by the built-in sensor exceeds the predetermined value. For example, if the temperature in the refrigerator becomes abnormally high during food delivery, the temperature sensor detects it and the alarm signal is sent via wireless LAN.

With the adoption of a low-power transceiver IC, the device ensures a maximum battery life of five years, in spite of using a small battery. (In the case of transmitting the measurement data once a minute, the battery life was measured with the use of an AA lithium primary battery, according to the company.)

The device uses a transceiver IC available from GainSpan Corp, a US venture company. The standby current consumption of GainSpan's IC is only 2μA. This is why the ZigNET-TAGMO can operate for a long time even though it uses wireless LAN as the transmission medium, the company said.

Hitachi Plant Technologies has already developed "ZigNET," a sensor network system with a long transmission range of about 10km. The ZigNET has been applied to the management of plant equipment, the monitoring of regional rivers and other purposes. With the adoption of the low-power transceiver IC, this time, the ZigNET-TAGMO can be applied to mobile objects as well.

According to the company, the ZigNET-TAGMO can be used to monitor children and elderly people, as well as for the management of traceability during food delivery, transportation of precision machinery, and farm and wild animals.

24 Hours | 7 Days