Selection of sensor number and locations in intelligent greenhouse

For monitoring and control of temperature inside an intelligent greenhouse, a network of wireless sensors is generally a better option rather than using a single sensor. Random location of sensors will yield an incorrect measurement of temperature profile inside the greenhouse. In addition, it will unnecessarily increase the number of sensors and the complexity of the wireless sensor network. In this paper, two approaches namely equal sensor spacing method and trial and error method for the selection of number and locations of sensors in a greenhouse have been proposed successfully investigated. In the equal sensor spacing method, the percentage error reduces from 1.3354% to 0.1559% as the number of sensors is increased from 3 to 10. Although the error corresponding to ten sensors is quite small, the large number of sensors would make the temperature measurement system very expensive. In case of trial and error method the least %error comes out to be 0.0658% corresponding to just five sensors placed at 1.0 m, 7.0 m, 11.0 m, 15.0 m and 19 m from the door. It is further observed that for this approach, increasing the number of sensors does not necessarily reduce the %error. Thus an optimal number of sensors at optimized locations result from this approach. It can be used for any temperature profile and applied along both the dimensions i.e. length and breadth of greenhouse.