What are sensors?
Sensors are devices that are used to measure physical or environmental parameters, such as temperature, light, sound, pressure, motion, or gas concentration, and convert them into electrical signals that can be processed by other devices.
Sensors play a critical role in many industries and applications, including the automotive, aerospace, medical, industrial, and consumer electronics sectors. By detecting changes in physical parameters, sensors can provide information about the environment and help control various processes.
There are many different types of sensors, each designed to measure a specific parameter. Some common types of sensors include: -Temperature sensors (e.g. thermistor, thermocouple) -Light sensors (e.g. photoresistor, photodiode) -Motion sensors (e.g. accelerometer, gyroscope) -Pressure sensors (e.g. barometer) -Proximity sensors (e.g. infrared, ultrasonic) -Environmental sensors (e.g. air quality, gas, humidity) -Others (e.g. sound, touch, magnetic, etc.)
Sensors are widely used in various applications, such as robotics, Internet of Things (IoT) devices, and control systems, to provide real-time information and enable automated decision-making.
What are gas sensors?
A gas sensor is an electronic device that is used to detect the presence and concentration of specific gases in the air. The most common types of gases that are detected by these sensors include carbon monoxide (CO), hydrogen (H2), methane (CH4), and propane (C3H8).
Gas sensors work by measuring changes in electrical resistance, conductivity, or voltage that are caused by the presence of a target gas. Each type of gas sensor is designed to detect a specific gas, and the output signal of the sensor will vary depending on the concentration of the target gas in the air.
In Arduino projects, gas sensors can be used to monitor indoor air quality, detect gas leaks in homes or buildings, or monitor the levels of specific gases in industrial environments. By connecting the gas sensor to an Arduino board, the output signal from the sensor can be read and used to trigger an alarm or other response in the event of a gas leak or other hazardous situation.
There are many different types of gas sensors available on the market, each with its own strengths and limitations. When selecting a gas sensor for an Arduino project, it is important to consider the type of gas that needs to be detected, the required sensitivity and accuracy, and the operating conditions (such as temperature and humidity) that the sensor will encounter.
List of Arduino Compatible Gas Sensors
| S.No. | Name of the sensor | Image | Material used for detection | Gas detected by the sensor |
| 1 | MQ135 Air quality sensor module |  | SnO2 | ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrous oxide |
| 2 | MQ2 Gas sensor module |  | SnO2 | Combustible Gas(LPG, propane, hydrogen, methane), Smoke |
| 3 | MQ3 Alcohol sensor module |  | SnO2 | Alcohol vapour |
| 4 | MQ4 Methane gas sensor module |  | SnO2 | Methane |
| 5 | MQ5 Gas sensor module |  | SnO2 | H2, LPG, CH4, CO, Alcohol |
| 6 | MQ6 Gas sensor module |  | SnO2 | Propane, Butane and LPG |
| 7 | MQ7 Gas sensor module |  | SnO2 | Carbon Monoxide |
| 8 | MQ8 Hydrogen H2 Gas sensor module |  | SnO2 | Hydrogen H2 |
| 9 | MQ9 Gas sensor module |  | SnO2 | Carbon Monoxide, Methane and LPG |
| 10 | MQ131 Gas sensor module |  | WO3 | Ozone |
| 11 | MQ136 Gas sensor module |  | SnO2 | Hydrogen Sulphide gas |
| 12 | MQ137 Gas sensor module |  | SnO2 | Ammonia |
| 13 | MQ138 Gas sensor module |  | SnO2 | Benzene, Toluene, Alcohol, Propane, Formaldehyde gas, Hydrogen, acetone, methanol |
| 14 | MQ214 Gas sensor module |  | SnO2 | Methane, Natural Gas, LPG, i-butane, propane |
| 15 | MQ216 Gas sensor module | SnO2 | Natural gas, Coal Gas | |
| 16 | MQ303A Gas sensor module |  | SnO2 | Alcohol, Ethanol, smoke |
| 17 | MQ306A Gas sensor module |  | SnO2 | LPG, LNG, iso-butane, propane, H2 |
| 18 | MQ307A Gas sensor module |  | SnO2 | Carbon Monoxide |
| 19 | MQ309A Gas sensor module |  | SnO2 | Carbon Monoxide, flammable gas |