Design and Development of an MQ-2 Sensor and Arduino Uno Gas Leak Detection System with Automatic Ventilation and Warning
Gas leakage can create fire, explosion, and health hazards when it is not detected promptly. This study developed a laboratory-scale gas-leak detection prototype that integrates an MQ-2 metal-oxide sensor, Arduino Uno, 16×2 I2C LCD, audible and visual warnings, a relay, and an automatically activated exhaust fan. Prototype performance was evaluated through distance-based sensor-response tests, alarm-response-time trials, and time-resolved ventilation tests. The average MQ-2 output declined from 721.0 ADC counts at 5 cm to 150.0 ADC counts at 30 cm, indicating a consistent distance-dependent response under the reported test conditions. The warning chain activated in an average of 2.0 s. After fan activation, the average ADC response decreased by 46.7% after 30 s and 79.9% after 60 s relative to the initial reading. These percentages describe changes in relative sensor output, not calibrated gas concentration, because no certified reference-gas or parts-per-million calibration was performed. The prototype demonstrates the feasibility of combining local detection, warning logic, and automatic ventilation in one low-cost platform. It is intended as an educational and supervised proof of concept and should not be treated as a substitute for a certified combustible-gas detector or explosion-protected safety system.