INTRODUCTION

1.1 Background of Study.

This project presents the design and implementation of gas detection system using GSM network. The gas detection system using GSM network is a newly designed gas detector device using MQ-6 gas sensor and microcontroller. It is a sophisticated gas detection method different from the existing system due to its unique features. The use of gas detector started with a gas detector system from Mr. Naoyoshi Taguchi which can measure the concentration of a target gas by oxidizing or reducing the target gas at an electrode and measuring the resulting current. Beginning his research in 1962, Mr. Naoyoshi Taguchi became the first person in the world to succeed in the development of a semiconductor device which could detect low concentrations of combustible and reducing gases when used with a simple electrical circuit. This gas detector device based on this technology are often called "TGS" (Taguchi Gas Sensors).

The sensors contain two or three electrodes, occasionally four, in contact with an electrolyte. The electrodes are typically fabricated by fixing a high surface area precious metal on to the porous hydrophobic membrane. The working electrode contacts both the electrolyte and the ambient air to be monitored usually via a porous membrane. The electrolyte most commonly used is a mineral acid, but organic electrolytes are also used for some sensors. The electrodes and housing are usually in a plastic housing which contains a gas entry hole for the gas and electrical contacts. The gas diffuses into the sensor, through the back of the porous membrane to the working electrode where it is oxidized or reduced. This electrochemical reaction results in an electric current that passes through the external circuit. In addition to measuring, amplifying and performing other signal processing functions, the external circuit maintains the voltage across the sensor between the working and counter electrodes for a two electrode sensor or between the working and reference electrodes for a three electrode cell. At the counter electrode an equal and opposite reaction occurs, such that if the working electrode is an oxidation, then the counter electrode is a reduction.