An embedded controller for greenhouse shade curtain.

摘要

The benefits of greenhouse cultivation in terms of total production and increase in revenues earned are bringing more and more area under greenhouse cultivation every year. The control of microclimatic parameters during the crop growth period, on daily and seasonal bases, could maximize the overall crop production over the whole season. The greenhouse environmental control using conventional control devices, such as, thermostat, humidistat or any other electro-mechanical device is highly inefficient and also requires manual attention most of the time. Therefore, microprocessor based environment control system has been considered for greenhouses. Out of all the important microclimatic parameters, light has been selected for this project to control the solar radiations in the greenhouse. The controller will not only control the solar radiations but also indirectly, achieve a temperature balance inside the greenhouse. The automatic shading curtain has been designed using off the shelf components, with low power consumption and cost efficient, 8-bit RISC microcontroller. An 8-bit AVR RISC controller with 1K Byte Flash (ATtiny15L) manufactured by ATMEL has been selected for this purpose. The controller is designed to sense the light intensity and based on set limits it actuates a control motor to operate shade curtain open or close. The shade curtain is coupled mechanically with shade cloth mounting system. The proposed controller will not only control the light levels incident in a greenhouse but also help in reducing expenditure incurred on cooling equipment to maintain the proper ambient temperature inside the greenhouse. There will also be savings on the extra billing accounting for the electricity consumed. The design is quite flexible as the coding can be changed any time, which proves to be an economical and cheaper solution for this type of greenhouse applications..