Experimental Profiling of Temperature and Luminosity inside Greenhouse using Wireless Sensor Network

Monitoring and control of climatic variables inside a greenhouse (GH) play crucial role in quality production of crops in the green-house (GH). Measurement and monitoring of major GH variables, such as temperature, humidity, soil moisture, light intensity and CO₂ in atmosphere, has been generally carried out using a central data acquisition system to which all sensors are individually wired. This technique involves huge cabling and lacks flexibility of adding sensors in future. This paper presents a detailed methodology and results of experimental measurement and profiling (both temporal and spatial) of temperature and luminosity inside a laboratory model of GH using a wireless sensor network (WSN). For the experimental work, the GH was divided into two rows, row 1 and row 2, with three zones of equal dimensions in each row. At the centre of each zone one wireless sensor node was placed for measurement and acquisition of temperature and luminosity in that zone. A WSN was created with these six wireless sensor (WS) nodes (or motes) and one network coordinator (NC). Profiling of temperature and luminosity was carried out under uncontrolled as well as controlled environmental conditions. Two controlled conditions were created. In the first case only temperature was controlled by placing a heater at the centre of GH. The second case involves simultaneous control of temperature and luminosity, for which an incandescent lamp was placed in each zone of row 1 while all the zones of row 2 were covered with a tinted plastic sheet. Data was gathered from all the six WS nodes in each controlled case as well as in uncontrolled environment. Surface profiles of both temperature and luminosity were drawn in Lab VIEW on the basis of collaborative processing of the data. The experimental results so obtained are correlated with the expected theoretical profiles. The use of WSN and Lab VIEW for collecting and processing the data, respectively, provides remarkable flexibility in terms of addition and deletion of WS nodes. Moreover, no wiring is needed for power or signals. (paper)