MQ Series Gas Sensor
Gas sensors, also referred to as gas detectors, are electronic devices designed to detect and identify various types of gases. They are commonly employed to identify toxic or explosive gases and measure gas concentration. Gas sensors play a crucial role in safety and security systems, especially in factories, manufacturing facilities, and residential environments. These sensors are used to detect gas leaks, smoke, and carbon monoxide in homes.
Gas sensors come in various sizes, ranging from portable to fixed models, and they vary in their sensing abilities and range. Typically, gas sensors are integrated into larger embedded systems, often connected to audible alarms or interfaces. Due to their continuous interaction with air and gases, gas sensors require frequent calibration compared to many other types of sensors.
The MQ series is a popular line of gas sensors, featuring Metal Oxide Semiconductor (MOS) technology, also known as Chemiresistors. These sensors detect gases based on changes in the resistance of the sensing material when in contact with gas. By employing a simple voltage divider network, concentrations of gas can be detected.
Here is a list of some commonly used MQ series gas sensors and the gases they detect:
MQ-2: Methane, Butane, LPG, smoke
MQ-3: Alcohol, Ethanol, smoke
MQ-4: Methane, CNG Gas
MQ-5: Natural gas, LPG
MQ-6: LPG, butane gas
MQ-7: Carbon Monoxide
MQ-8: Hydrogen Gas
MQ-9: Carbon Monoxide, flammable gases
MQ131: Ozone
MQ135: Air Quality (CO, Ammonia, Benzene, Alcohol, smoke)
MQ136: Hydrogen Sulfide gas
MQ137: Ammonia
MQ138: Benzene, Toluene, Alcohol, Acetone, Propane, Formaldehyde gas, Hydrogen
MQ214: Methane, Natural gas
What is 1 PPM equal to?
When measuring gases such as carbon dioxide, oxygen, or methane, concentration describes the volume of gas in the air. The two most common units of measurement are parts per million (ppm) and percent concentration.
Parts per million (abbreviated ppm) represents the ratio of one gas to another. For instance, 1,000 ppm of CO implies that among a million gas molecules, 1,000 would be carbon monoxide, while the remaining 999,000 molecules would consist of other gases.
MQ-2 Gas Sensor
The Gas Sensor (MQ2) module is valuable for detecting gas leaks in both home and industrial settings. It is capable of detecting H2, LPG, CH4, CO, Alcohol, Smoke, or Propane. With its high sensitivity and rapid response time, measurements can be obtained promptly. Additionally, the sensor's sensitivity can be adjusted using the potentiometer.
MQ-3 Gas Sensor
The Gas Sensor (MQ3) module is valuable for detecting gas leaks in both home and industrial environments. It is capable of detecting Alcohol, Benzine, CH4, Hexane, LPG, and CO. With its high sensitivity and rapid response time, measurements can be obtained promptly. Additionally, the sensor's sensitivity can be adjusted using the potentiometer.
MQ-4 Gas Sensor
The MQ-4 Natural Gas Sensor is designed specifically as a natural gas sensor, offering rapid and reliable detection with high sensitivity to natural gas and methane, along with good sensitivity to propane and butane. This sensor boasts a long lifespan and is cost-effective, making it widely utilized for gas leak detection. In addition, the project incorporates two LED lights to indicate gas concentration:
Green Light: Indicates that the natural gas concentration is below the critical value.
Red Light: Alert! Indicates that the natural gas concentration has exceeded the critical value.
MQ-5 Gas Sensor
The Gas Sensor (MQ5) module is valuable for detecting gas leaks in both home and industrial environments. It is capable of detecting H2, LPG, CH4, CO, and Alcohol. With its high sensitivity and rapid response time, measurements can be obtained promptly. Additionally, the sensor's sensitivity can be adjusted using the potentiometer.
MQ-6 Gas Sensor
This is a user-friendly liquefied petroleum gas (LPG) sensor, MQ-6-LPG, designed for detecting LPG (primarily composed of propane and butane) concentrations in the air. The MQ-6 sensor is capable of detecting gas concentrations ranging from 200 to 10,000 ppm.
With high sensitivity and a fast response time, this sensor provides reliable performance. Its output is in the form of analog resistance. The drive circuit is straightforward; all that is required is to power the heater coil with 5V, include a load resistance, and connect the output to an ADC.
MQ-7 Gas Sensor
The MQ-7 gas sensor utilizes SnO2 as its sensitive material, which exhibits lower conductivity in clean air. The detection process involves cycling between high and low temperatures to identify CO when at a low temperature (heated by 1.5V). As the gas concentration increases, the sensor's conductivity also increases. At high temperatures (heated by 5.0V), it eliminates other gases adsorbed at low temperatures. A simple electro-circuit is used to convert changes in conductivity into a corresponding output signal of gas concentration. With its high sensitivity to Carbon Monoxide, the MQ-7 gas sensor is capable of detecting different gases containing CO. It is cost-effective and suitable for various applications.
MQ-8 Gas Sensor
The Hydrogen Gas Sensor is designed to measure the concentration of Hydrogen (H2) in the air, suitable for measuring concentrations ranging from 100 to 10,000 ppm. It features an easy-to-implement heater drive and measuring circuit. This sensor is engineered for long life and stable output. Our MQ-8 Hydrogen Gas Sensor is an ideal choice for use in gas leakage circuits to detect gas leaks.
MQ-131 Gas Sensor
The MQ131 gas sensor utilizes SnO2 as its sensitive material, which exhibits lower conductivity in clean air. In the presence of Ozone gas, the sensor's conductivity increases with rising gas concentration. To convert changes in conductivity into a corresponding output signal of gas concentration, a simple electro-circuit is employed. The MQ131 gas sensor is highly sensitive to Ozone and also detects CL2, NO2, and other gases.
MQ-135 Gas Sensor
The air quality sensor is designed to detect a broad spectrum of gases, such as NH3, NOx, alcohol, benzene, smoke, and CO2, making it ideal for use in offices or factories. The MQ135 gas sensor exhibits high sensitivity to Ammonia, Sulfide, and Benzene steam, as well as being sensitive to smoke and other harmful gases. With its cost-effective nature, it is particularly suitable for air quality monitoring applications.
MQ-136 Gas Sensor
The MQ136 gas sensor utilizes SnO2 as its sensitive material, which exhibits lower conductivity in clean air. In the presence of the target Hydrogen sulfide gas, the sensor's conductivity increases with rising Hydrogen sulfide concentration. To convert changes in conductivity into a corresponding output signal of gas concentration, a simple electric circuit is employed. The MQ136 gas sensor demonstrates high sensitivity to Hydrogen sulfide and low sensitivity to other combustible gases. It is cost-effective and suitable for various applications.
MQ-137 Gas Sensor
The MQ-137 Gas sensor is capable of detecting or measuring gases such as Ammonia (NH3) and Carbon Monoxide (CO). The module version of this sensor is equipped with a Digital Pin, allowing it to operate even without a microcontroller. This feature is particularly useful when you only need to detect a specific gas. However, when measuring the gas in parts per million (ppm), the analog pin must be used. The analog pin is also TTL driven and operates on 5V, making it compatible with most common microcontrollers.
MQ-138 Gas Sensor
The MQ138 gas sensor utilizes SnO2 as its sensitive material, which exhibits lower conductivity in clean air. When the target organic steam is present, the sensor's conductivity increases with the rising gas concentration. A simple electro circuit is used to convert changes in conductivity into a corresponding output signal of gas concentration.
The MQ138 gas sensor demonstrates high sensitivity to Toluene, Acetone, Ethanol, and Formaldehyde, as well as other organic steam. It can be effectively used to detect various organic steams and is cost-effective, making it suitable for a range of applications.
MQ-214 Gas Sensor
The MQ-214 Methane (CH4) gas sensor is designed to detect the concentrations of methane in the air and provides its reading as an analog voltage output. It's important to note that the gases detected by these gas sensors can be lethal in high concentrations. Always exercise caution and perform gas tests in well-ventilated areas.
