Air Quality Monitoring in a Home Using a Low-Cost Device Built Around the Arduino Mega 2560 Platform

The article is aimed to present the construction and test of a low-cost prototype device for monitoring indoor air quality to enhance human comfort, health, and safety. The device was built around the Arduino Mega 2560 platform to which several sensors are connected, such as DHT11, MQ-2, MQ-3, MQ-4, MQ-7, MQ-9, and MQ-135. The main objective was to incorporate in a single device as many sensors as possible, each detecting a certain type of gas (methane, ethanol, LPG, liquefied methane, hydrogen) or dangerous substances (carbon monoxide, alcohol vapors, smoke) to respond to the widest possible range of factors that can affect people's health and safety. Neither the temperature nor the humidity has been forgotten, which can contribute to the discomfort of the inhabitants. For each of the risk factors, a certain level can be set, which if exceeded will cause the device to warn (sound and through messages displayed on an LCD display or transmitted via Bluetooth to a smartphone) the residents. The device was built and tested at the Transilvania University of Brasov in the Medical Engineering Laboratory.