A wireless sensor network-based monitoring system with dynamic convergecast tree algorithm for precision cultivation management in orchid greenhouses

The orchid industry in Taiwan has established large-scale orchid greenhouses to achieve high-precision cultivation of orchids, especially for Phalaenopsis. The wireless sensor network (WSN) technology has been shown to be able to play an important and useful role for effectively acquiring environmental parameters in real-time. However, the mobile benches equipped with different sensors used in an orchid greenhouse create a problem of susceptible dynamic network topology. To meet the requirements of reliable data acquisition in the monitoring of orchid growth, a novel dynamic convergecast tree algorithm (DCTA) based on a tree-like topology was designed and implemented in the WSN-based monitoring system. The proposed WSN algorithm uses the information of the received signal strength indication and hop count to dynamically adjust the routing path of each sensor node. The proposed algorithm includes a flexible scheduling-based design for the medium access control protocol to guarantee higher transmission reliability of the sensor data. An extensive series of experiments, including tests in the lab and an orchid greenhouse, were conducted to examine the performance of the proposed DCTA. The experimental results show that the proposed algorithm can reliably collect environmental data; average successful data delivery rates up to 92.5 % of the entire tested networks with multiple mobile nodes in the greenhouse can be achieved. The WSN-based monitoring system equipped with the proposed DCTA provides environmental measurements with better spatio-temporal resolution to achieve precision cultivation management for orchids.