Embedded Webblog

With the proliferation of Wi-Fi networks embedded designers are turning to wireless interfaces to eliminate the expensive wiring and installation costs for commercial and industrial sensing applications. The major challenge has been the relatively short battery life for remote sensors interfaced through the wireless network. RF Monolithics recently announced a potential solution with their new Wi-Fi sensor networking module. The WSN802G is a low-power, low-cost, 802.11 b/g module suitable for wireless sensor networking applications due to its ability to operate for years on battery power. To achieve its low power consumption and long battery life, the WSN802G combines 1 Mb/s and 2 Mb/s data rates, which are appropriate for most sensing applications, with an advanced sleep management feature that puts the module to sleep between active periods. Depending upon the frequency of active periods, a single AA Lithium cell can provide a battery life in excess of 5 years. When the module is active, its current consumption is less than 200 mA, allowing a battery to adequately power the device. Its sleep current consumption is less than 8 uA. Typical transmission ranges are 50 meters indoors and 250 meters outdoors. The WSN802G features a 1.0 x 1.05 inch footprint and a $69 price tag for single units or $39 in quantities of 10,000 or more. The WSN802GDK developer kit will also be available by the end of April 2009 to help design engineers fast track their applications.