Development of a smart greenhouse monitoring system based on WSN, 3G and PLC technologies

Abstract. It is very convenient for farmers to control the devices located in greenhouses remotely and precisely. A smart greenhouse monitoring system was developed based on WSN, 3G and PLC technologies. It consists of a WSN, a 3G communication unit, a PLC control unit and devices (air fans and roller shutter door) in each greenhouse and a monitoring application running on the greenhouse server. The system manages greenhouse for each registered farmer. The WSN is developed using ZigBee technology and each WSN node integrates environment humidity sensor and temperature sensor, and the power for each sensor can be disenabled by the wireless node itself after sending data for 10 times and enabled when receiving the data collecting command from the coordinator. There is a ZigBee coordinator in each greenhouse and it is integrated with a 3G module and a PLC unit. Furthermore, the MCU in ZigBee coordinator is used as the CU for the integrated setup. The devices installed in each greenhouse are connected with the PLC unit and can be triggered and controlled by the PLC module. The WSN collects all of data in given interval. The 3G module is responsible for establishing the connection with the greenhouse server, uploading the collected data to the server and downloading the commands from the server. The PLC unit receives the commands forwarded by the CU and controls each device to execute the specific action.