Review of sensors for greenhouse climate monitoring

A greenhouse provides shelter and protects plants from harsh environment and external interferences. It allows plants to grow under an optimum condition which maximizes the growth potential of the plants. The existing systems only allow for the monitoring of climate variables such as temperature or humidity and often overlook many other important factors such as CO₂, light, soil moisture, soil temperature etc. Neglecting these climate factors leads to inaccurate observation of the overall greenhouse climate condition. To make up for this weakness, the prototype designed for this particular research will allow better monitoring of the climate condition in a greenhouse by integrating several sensor elements such as CO₂, temperature, humidity, light, soil moisture and soil temperature into the system. The purpose of this paper is to provide a review of a range of popular sensors on the market. The paper also discusses their operating principles as well as addresses their advantages and disadvantages. Experiments were carried to test the accuracy of the sensors and the results indicate that the sensors used in this project are relatively accurate and have good stability.