Design And Fabrication Of A Greenhouse Monitoring And Control System Based On Global System For Mobile Communication And Bluetooth

ABSTRACT

Greenhouse technology should be embraced as a way of minimizing food insecurity in Kenya. The insecurity is brought about by climate uncertainties. Greenhouses have attempted to solve this problem by enclosing crops in a climatically controlled environment. Each greenhouse has distinct parameters. Data on these parameters need to be collected at regular intervals. Depending on the type of crop, these parameters need to be controlled within the specified limits to achieve the maximum efficiency and yields. In the past, greenhouses utilized electromechanical devices such as thermostats to monitor and control the environment. Mechanical systems lack the flexibility and precision required for greenhouse control. Some modern greenhouses use computers to control the environment. Computers based controllers are station based, bulky and costly. In this study a wireless prototype greenhouse monitoring and control system that is flexible, cheap, easy to maintain and easy to assemble was developed and implemented. The general objective of this research work was to design, fabricate and implement a microcontroller-based prototype to monitor and control greenhouse parameters using sensors, SMS technology and Bluetooth signals. The hardware consisted of ATmega328 microcontroller, Global System for Mobile communication (GSM) SIM800L module, HC05 Bluetooth module, HD44780U Liquid Crystal Display (LCD) module, 5 volt 4 channel relay module, Light dependent resistor (LDR) sensor and digital humidity and temperature (DHT11) sensor. The LDR sensor was utilized to measure light intensity while the DHT11 sensor was utilized to measure humidity and temperature levels in the prototype greenhouse. The DHT11 and LDR sensors, the relay, the LCD, the GSM and the Bluetooth modules were interfaced to the ATmega328 microcontroller. Through Arduino software, a program was written in C language, developed and uploaded to the ATmega328 microcontroller to run the greenhouse prototype. The program is designed to operate in automatic or manual mode. In automatic mode, the microcontroller constantly monitors the digitized values from the sensors and compares them with the optimized values and checks if any control procedures needs to be taken. In manual mode, the system could be operated wirelessly by use of GSM or Bluetooth module. The designed prototype greenhouse system is able to measure temperature, humidity and illuminance levels in the prototype greenhouse and display the values on the LCD. The system transmits the sensor measured values to owner’s phone via Bluetooth or a GSM and keeps these parameters at optimum levels by use of two fans, heater, bulb and a sprinkler. The GSM module is used for remotely monitoring and controlling the devices via a smart phone by sending and receiving Short Messaging Service via GSM network. If the user is in the vicinity of the prototype, the Bluetooth and a software installed in the smart phone provides a wireless link between the prototype and the cell phone. This project therefore provides a cost effective and efficient means of monitoring and controlling greenhouse parameters. In addition the system allows mobility during monitoring and control process. The reliability of the designed system can be exploited to build a network of such monitoring and control systems for several greenhouses. A website can be incorporated in the designed system to monitor the actual greenhouse values and save the data in an online database for future reference. The designed prototype greenhouse can be applied in the agricultural sector in the design and implementation of greenhouses