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Seeed Gas Sensor Selection Guide

Gas sensor is a device which can detect the presence of various toxic and combustible gases present in the environment.

Operating Principle

The interaction between the test gas and the sensing surface can be detected by the measurements of change in resistance, capacitance, work function, mass, optical characteristics etc. Below table is from Source1.

Class of gas sensors Operating principle
Electrochemical Changes in current, voltage, capacitance/impedance: 1. Voltammetry (including amperometry) 2. Potentiometry 3. Chemically sensitized field-effect transistor 4. Potentiometry with solid electrolytes for gas sensing
Electrical Metal oxide conductivity Organic conductivity Electrolytic conductivity Heterojunction conductivity (Schottky diode, FET, MOS) Work function Electric permittivity (capacitance)
Mass sensitive Changes in the weight, amplitude, phase or frequency, size, shape, or position: 1. Quartz crystal microbalance 2. Surface acoustic wave propagation 3. Cantilever
Magnetic Changes of paramagnetic gas properties
Optical devices Changes in light intensity, color, or emission spectra: 1. Absorbance 2. Reflectance 3. Luminescence 4. Refractive index 5. Optothermal effect 6. Light scattering (Raman scattering, plasmon resonance)
Thermometric (calorimetric) Heat effects of a specific chemical reaction. Changes in temperature, heat flow, heat content: 1. Thermoelectric 2. Pyroelectric 3. Catalytic bead (pellistors) 4. Thermal conductivity
Table 1.The classification of gas sensors suggested in 1991 by Analytical Chemistry Division of IUPAC,

Field of Applicaitons

There are a numerous use of these gas sensors. Particularly, using these gas sensors human beings can be saved from potential dangers. Hence the gas sensors play important roles in various sectors, which include industry, medical, environmental applications, and domestic applications for monitoring toxic and flammable gases. Below table is from Source2.

Field of application Function Examples of detected gases
Environment Monitoring toxic gases present in the atmosphere, due to industrial emissions (weather stations, pollutionmonitoring) CO, CH4, humidity, CO2, O3, VOCs, SOx
Safety at work Control of indoor air quality; monitoring toxic gases in a working environment, for instance in a factory where dangerous chemicals are used Toxic gases, combustible gases, O2
Domestic safety/household application Detection of poisonous gases or smoke in households, due to accidents such as fires and explosions; intelligent refrigera­tor or oven; fire alarm; natural gas heating; leak detection; air quality control; air purifiers; cooking control CO, humidity, CO2, VOCs
Safety in car Car ventilation control; gasoline vapor detection; alcohol breath tests CO, LPG, VOCs, CH4
Public security Control of indoor air quality, detection of substances dangerous for the safety of the general public Toxic gases, combustible gases, flammable gases, explosives, O2
Medical/clinical Diagnostics(breath analysis, disease detection); point-of-care patient monitoring; drug monitoring; artificial organs and prostheses; new drug discovery O2, NH, NOx, CO2, H2S, H2, CL2, anesthesia gases
Agriculture Plant/animal diagnostics; soil and water testing; meat/poultry inspect ion; waste/sewage monitoring amines, humidity, CO
Food quality control Detection of particular molecules, which are formed when food starts to rot and it is no longer good for consumption humidity, CO2
Utilities/automotive/power plants Control of the concentration of the gases in the engine and gas boiler, to guarantee the highest possible efficiency of the combustion process. The same concept can also be applied to power plants, as the energy is generated by combustion O2, CO, HCs, NOx, SOx, CO2, H2, HCs
Industry: Petrochemical Steel/Water treatment/Semiconductor Process monitoring and control; quality control; workplace monitoring; waste stream monitoring; leakage alarm HCs, conventional pollutants, O2, H2, O3, CO2, CL2, CH4,H2S
Defense/military Detection of chemical, biological, and toxin warfare agents; treaty verification Agents, explosives, propellants
Aerospace Monitoring of oxygen and toxic and flammable gases in the environ­ment atmosphere H2, O2, CO3, humidity
Traffic/tunnels/car parks City traffic control and management; air quality monitoring in tunnels or underground parking garages
Table 2.Some examples of gas sensor applications

Seeed Gas Sensor

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Name Target Gas Class of gas sensors Field of application Sensor Detecting Range Accuracy Operate voltage Interface Click to Buy
Grove - Air Quality Sensor v1.3 Alcohol, Smoke Electrochemical Environment MP503 10-1000ppm(Alcohol) NA 3.3V 5V Analog Order
Grove - Alcohol Sensor Alcohol Electrochemical Safety in car Public security MQ303A 20-1000ppm Alcohol NA 5V Analog Order
Grove - CO2 Sensor CO2 Electrochemical Environment Agriculture MH-Z16 0-5000ppm ±(50ppm +5%) 5V UART Order
Grove - CO2 & Temperature & Humidity Sensor (SCD30) CO2 Optical devices Environment Agriculture SCD30 0-40000ppm ±(30 ppm + 3%) 3.3V 5V I2C Order
Grove - VOC and eCO2 Gas Sensor (SGP30) VOC,CO2 Electrical Environment Agriculture SGP30 VOC: 0 ppb to 60000ppb CO2: 400 ppm to 60000 ppm VOC: (0-2008ppb/1ppb, 2008-11110ppb/6ppb, 11110-60000ppb/32ppb) CO2: (400-1479ppm/1ppm, 1479-5144ppm/3ppm, 5144-17597ppm/9ppm, 17597-60000ppm/31ppm) 3.3V 5V I2C Order
Grove - Gas Sensor(MQ2) LPG, i-butane, propane, methane, alcohol, Hydrogen, smoke Electrochemical Domestic safety/household application Safety at work MQ2 LPG and propane: 200ppm-5000ppm Butane: 300ppm-5000ppm Methane: 5000ppm-20000ppm H2: 300ppm-5000ppm Alcohol:100ppm-2000ppm NA 5V Analog Order
Grove - Gas Sensor(MQ3) High sensitivity to alcohol and small sensitivity to Benzine Electrochemical Safety in car Public security MQ3 Alcohol: 0.05-10mg/L NA 5V Analog Order
Grove - Gas Sensor(MQ5) High sensitivity to LPG, natural gas, town gas and Small sensitivity to alcohol, smoke Electrochemical Industry: Petrochemical Steel/Water treatment/Semiconductor Utilities/automotive/power plants MQ5 200-10000ppm NA 5V Analog Order
Grove - Gas Sensor(MQ9) High sensitivity to carbon monoxide and CH4,LPG Electrochemical Safety in car Industry: Petrochemical Steel/Water treatment/Semiconductor Utilities/automotive/power plants Domestic safety/household application MQ9 Carbon monoxide: 20-2000ppm CH4: 500-10000ppm LPG: 500-10000ppm NA 5V Analog Order
Grove - Gas Sensor(O2) O2 Electrochemical Safety in car Industry: Petrochemical Steel/Water treatment/Semiconductor Utilities/automotive/power plants Domestic safety/household application ME2-O2-Ф20 0~25%Vol NA 3.3V 5V Analog Order
Grove - HCHO Sensor Toluene, methanal, benzene, alcohol, acetone Electrochemical Environment WSP2110 1~50ppm NA 3.3V 5V Analog Order
Grove - Multichannel Gas Sensor Carbon monoxide,Nitrogen dioxide, Ethanol, Hydrogen, Ammonia, Methane, Propane, Iso-butane Electrical Environment MiCS-6814 CO: 1–1000ppm NO2: 0.05–10ppm H2: 10–500ppm C2H5OH: 1-1000ppm NH3: 1-500ppm CH4: >1000ppm C3H8: >1000ppm C4H10: >1000ppm NA 3.3V 5V I2C Order
Grove - Temperature, Humidity, Pressure and Gas Sensor (BME680) IAQ Electrical Environment Domestic safety/household application BME680 0-500 NA 3.3V 5V I2C Order
Table 3.Seeed Gas Sensor Category

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  1. Source: Reprinted from I lulanicki et al. (1991). Published by International Union of Pure and Applied Chemistry. 

  2. Source: Data from Taylor (1996), Stcttcr et al. (2003), Capone ct al. (2003), etc. HCs hydrocarbons, VOCs volatile organic compounds.