Implementation of Wireless Sensors Network for Automatic Greenhouse Monitoring M. Fezari*, A. Khati** and M. S. Boumaza*** * Laboratoire de Sinax et Automatique LASA), Departement d'electronique UniversiteBaji Mokhtar Annaba ** Laboratoire de Physique des Rayonnements (LPR), Departement de physique Departement de physique, Faculte des sciences, Universite Baji Mokhtar *** Laboratoire de Physique de Guelma (LPG), Departement de Genie electrique Universite 08 ?ai 1945 Guelma Mohamed. f ezari@uwe.ac.uk, a.khati@yahoo. f r Abstract-A hardware design and sotware simulation are presented to control and monitoring greenhouse parameters such as: air temperature, humidity provision and irrigation by means of simultaneous ventilation and enrichment. A set of smart wireless sensor modules to control and monitoring system were designed and tested. The heart of the smart sensor is a microcontroller that receives data on greenhouse environment conditions from many sensors installed inside and outside. The smart sensor transfers the data to and from a PC via a wireless transmission system. Accordingly, it changes the state of greenhouse command devices, heaters, fans and vapor injectors to reach the desired condition. A friendly GUI using high level language was developed to carry out the monitoring tasks. The program implements the control algorithms comparing the received data with set points, sending control signals to the smart sensors in order to reach the desired conditions. Performance of the designed system was tested by installing it in the model greenhouse with a set of smart sensors. Keywords-component; Greenhouse control, node sensors, wireless sensors network, microcontroller. 1. INTRODUCTION Many research projects study possibilities for improvement of existing greenhouses an/or control systems in these greenhouses. Oten, it is necessary to develop an enhanced measurement and control system to facilitate these studies, since commercially available systems do not provide the necessary lexibility for this type of research. For example, it oten happens that new control laws cannot be implemented in the available sotware, or that the number of measurements is limited. For instance, in many advanced control studies it is necessary to have access to the low-level manipulators directly [1 - 4]. Apart rom developing a completely new control system, one way to handle the limitations of commercially available systems is to connect a PC to the commercial climate computer. This PC runs advanced algorithms that generate set-points, which are sent to the climate computer. II. MATERIALS AND METHODS One of the most important tasks of the measurement and control system is to measure all data needed to study the behavior of the greenhouse and to gain enough information for modeling of the greenhouse climate and validation of these models. The sensors installed in the greenhouse and considerations to be taken into account when choosing these sensors can be mentioned here: Temperature is measured outside, in the greenhouse, in the soil and in the water circuits at various locations. For comparable data the same type of sensor is used at all locations. DS1620 sensors were selected, since, at the same level of accuracy, these sensors offer better reliability and long term stability than altenatives like thermocouples and thermostats. Moisture content can be measured very accurately with the principle of wet/dry bulb temperatures. In our case however most H sensors are diicult to reach, which complicates illing the water container of the wet bulb sensor. Therefore electronic humidity sensors were selected. Ater calibration their accuracy is good enough for greenhouse experiments and they are more reliable thn other options since no requent maintenance is required. Most dominant drawback is that electronic H sensors do not unction when condensation occurs on the sensor. CO2 concentration is measured with a commercially available CO2 sensor that works according to the inra red measurement principle, see re. [5] and [6]. These sensors are small, do not have a long response time (as some centrally placed analyzers) and do not require requent maintenance. Air velocity is measured both inside the heat exchanger as well as outdoors (wind speed). The latter is easy to measure with commercially available wind sensors (rotating turbine wheel) as in igure 1. Moreover, Wireless Sensor Networks (WSNs) generally consist of a large number of low-cost, low-power, multiunctional sensor nodes that are small in size and communicate over short distances [1]. Their structure and characteristics depend on their electronic, mechanical and communication limitations but also on application-speciic requirements. In WSNs, sensors are generally deployed