By: Chris Downey, Product Manager
Wireless Sensor Networks (WSN) are specialized wireless networks designed to provide communications between distribute sensors, such as those that monitor temperature, sound, pressure or humidity. Applications for WSNs are extensive as new technologies are developed to produce sensors, wireless transceivers and database systems to handle the large quantity of data. WSNs are being used in facilities management to provide critical information about buildings, in agriculture to provide information on the soil, moisture and the crop conditions, in forestry service for fire detection and in industrial controls systems to provide for safer and more efficient processes. Many of the applications for WSNs are unique as the technology to produce a distributed sensor network did not exist until it was enabled by new wireless technologies.
Wireless Sensor Network
WSNs are unique in that the networks often consist of hundreds or even thousands of low power sensors. Sensors often achieve this low power, long battery life by utilizing sleep conditions which allow the sensor node to sleep for long periods of time. For multihop mesh networks, this sleeping behavior can be problematic because a packet’s route back to a central node is frequently changing. Further, due to the low processing power at end nodes, sensor networks often take advantage of a central controller to store sensor information and direct any actions. Effectively, this makes most wireless sensor networks a star topology in terms of the data path, not a true mesh network. Very large WSNs which may consist of many devices and cover many square miles or face significant obstructions will probably need to use a router or repeater to route information back to a central node. For networks that are looking to cover less than a few miles though, point to multipoint wireless systems such as Laird’s RAMP ISM Modules can provide connectivity without a cumbersome routing network.
RAMP modules, such as the RM024, are ideal for WSNs as they offer an ability to provide connectivity for a nearly unlimited number of wireless sensors back to a central gateway or processor. RAMP modules’ Point to Multipoint feature allows remote nodes to transmit on an add -needed basis, so network traffic is not utilized unless they are transmitting actual sensor data. Further, RAMP modules feature very low current consumption, less than 10mA average in idle conditions, and sleep modes to allow them to be used in battery powered sensor nodes. Finally RAMP modules are available in various output powers and with excellent receive sensitivity to provide very long range for point to multipoint networks. RAMP 900Mhz modules such as the AC4490 and LT1110 are available in output powers from 10mW to 1000mW. The RAMP 2.4Ghz RM024 is available in 10mW and 125mW ranges. The RM024 125mW modules are fully approved for FCC use and with a potential range of 4km, which would cover a potential area of 50m2.
Check out all our RAMP ISM modules here: http://www.lairdtech.com/ramp.