The CWS900A available from Campbell Scientific Aust is a line of 900 MHz wireless sensor interfaces that allows a variety of sensors to be used in a wireless sensor network.
CWS900A wireless sensor interfaces contain an internal 900 MHz spread spectrum radio that transmits data to the CWB100 wireless base station or to another wireless sensor using a particular frequency commonly employed in the US and Canada.
A wireless sensor can route its transmissions through up to three other wireless sensors. A datalogger is connected to the CWB100 base station for processing and storing the CWS900's data.
Wireless sensors are useful for making measurements in locations where the use of cabled sensors is problematic.
Protecting cables by running them through conduit or burying them in trenches is time consuming, labour intensive, and sometimes not possible. Local fire codes may additionally preclude the use of certain types of sensor cabling inside of buildings.
In some applications measurements need to be made at distances where long cables decrease the quality of the measurement or are too expensive.
There are also times when it is important to increase the number of measurements being made but the datalogger does not have enough available channels left for attaching additional sensor cables.