Design and Fabrication of 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. Greenhouses have attempted to solve this problem by enclosing crops in a climatically controlled environment. In the past, greenhouses utilized electromechanical devices such as thermostats to monitor and control the greenhouse environment. Mechanical systems lack the flexibility and precision required for greenhouse control. Some modern greenhouses use computers -based controllers, which 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 hardware consisted of ATmega328 microcontroller, Global System for Mobile communication (GSM) SIM800L module, HC05 Bluetooth module, HD44780U Liquid Crystal Display (LCD) module, 5 volts 4 channel relay module, Light dependent resistor (LDR) sensor and digital humidity and temperature (DHT11) sensor. 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 designed prototype system is able to measure temperature, humidity, and light illuminance levels in the prototype greenhouse and display the values on the LCD. The system also transmits the measured values to owner’s phone via Bluetooth or GSM and keeps these parameters at optimum levels by use of two fans, a heater, a bulb and a sprinkler. From results, when the actuators were on, the average internal temperature was 24.5 ºC while the average external temperature was 31.43 ºC. The average temperature control effect and cooling efficiency per hour for the designed prototype were 6.9 ºC and 75.9%, respectively. At stable cooling state, the maximum cooling efficiency was 78%. 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 agricultural sector in Kenya, can apply the designed prototype in the design and implementation of greenhouses.