Multi-sensor Integrated System for Wireless Monitoring of Greenhouse Environment

Several parameters contribute to the growth of plants in a commercial greenhouse, namely soil moisture, soil temperature, atmospheric temperature and humidity, carbon dioxide (CO2) and light intensity. Maintaining optimal levels of these environmental parameters is essential for healthy growth of the plants and to maximise yields in terms of fruits and flowers. Monitoring only a few parameters, such as temperature and humidity, while neglecting others, leads to inaccurate observations and sub-optimal yields. At the same time, increases in greenhouse sizes have forced the growers to increase measurement points (sensor stations) to accurately track changes in the environment. However, increases in measurement points mean increases in installation and maintenance cost of the sensor stations. In this paper, an automated wireless greenhouse climate monitoring system has been detailed with special emphasis on the programming aspects and testing of a temperature and humidity sensor. The proposed system consists of three units-Sensor Station (SS), Coordinator Station (CS) and Central Control Station (CCS). The backbone of the wireless network is based on ZigBee modules for communication between the SS and CS whereas the communication between the CS and CCS uses a XStream proprietary RF modem. Field trials conducted have established the functionality and reliability of the designed wireless sensor network. The overall system architecture shows advantages in cost, size, power, flexibility and distributed sensing.