Design of an auto disconnecting regulator and a safety switch to prevent domestic gas leakages

There is a growing demand for research in various aspects of smart homes. Automated security systems are an integral part of smart homes. Liquid Petroleum Gas (LPG) is one of the popular fuels used in domestic cooking. Therefore, there is a very high demand for LPG fire security systems. In this study, an automated LPG fire security system for domestic gas leakages has been designed and a prototype model is constructed. The designed system automatically takes preventive measures in case of gas leakage. It includes a newly designed automatically disconnecting regulator from the cylinder which shuts OFF gas supply from commercially available gas cylinders, a control circuit for switching OFF the power supply of nearby area of gas leakage and transceiver unit for sending SMS to the corresponding people. It has been designed to operate automatically when LPG concentration reaches to 200 PPM, a value well below the LPG gas inflammable concentration. LPG concentration is sensed by the MQ-5 gas sensor and fed into the microcontroller. The commercially available gas regulator is modified by attaching a spring and solenoid valve. The spring is compressed when the regulator is ON. Once an LPG leakage of appropriate PPM is detected, a pulse is sent to the solenoid valve such that the attached spring gets rest by removing the regulator from the cylinder. At the same time, a warning message will automatically send to the corresponding users and security personnel through a GSM module attached to the circuit. The circuit is embedded with a rechargeable battery to work even in power outage. Additional gas sensors are installed in electrical switches located near to the gas cylinder and kept in connection with the microcontroller through the Bluetooth module to cutoff electrical power to prevent any spark.