What is a carbon dioxide sensor?
A CO2 Sensor is a device that finds gas. It is mainly used to measure how much carbon dioxide (CO2) is in the air. It is important to check air quality. We need to make sure it meets acceptable standards.
When CO2 levels are much higher or lower than normal, the sensor sounds an alarm. This alarm prompts people to take action. These devices are used in many industries and daily life. They help make the environment better.
Key industries that use CO2 sensors include beer making, soft drinks, coal mining, farming, and home air quality. These sensors may not be used in many situations, but they are very useful in certain cases.
To choose the best CO2 sensor for you, it’s important to know how they work. You should also consider their pros and cons. Four common variants are detailed below:
Non-Dispersive Infrared (NDIR) CO2 Sensors
Electrochemical CO2 Sensors
Semiconductor CO2 Sensors
Catalytic Combustion CO2 Sensors
1. Non-Dispersive Infrared (NDIR) CO2 Sensors
This type of sensor works on the idea that different substances absorb infrared radiation at certain wavelengths. An internal infrared lamp gives off light in a specific range. This light goes through the gas sample that is being measured.
The gas changes the strength of the infrared light. This lets the sensor measure CO2 levels by looking at the change. The signal is cleaned and made stronger.
Then, it is changed with an ADC. ADC stands for analog-to-digital conversion. After that, a microprocessor system processes the signal.
This system changes for things like temperature and pressure. In the end, it gives the final measurement.
Benefits: High sensitivity, fast analysis speed, great stability, and a long lifespan.
Disadvantages: High power use, complex design, and higher costs from advanced hardware and software.
2. Electrochemical CO2 Sensors
These sensors measure CO2 levels. They do this by turning CO2 into an electrical signal using chemical reactions.
Electrochemical sensors come in three types. These are potential-type, current-type, and capacitive-type. They differ in how they read electrical signals.
They can use either liquid or solid electrolytes. Solid electrolyte CO2 sensors have gained a lot of interest from researchers since the 1970s.
The main idea is that a gas-sensitive material makes ions when gas flows through it. This creates a force that can be measured to find out the gas concentration.
Benefits: Fast measurement times, simple to use, and low cost.
Disadvantages: They do not last long and can change or move over time. They can lose accuracy and be affected by other gases. This can impact how reliable the measurements are.
3. Semiconductor CO2 Sensors
Semiconductor gas sensors work by using gas molecules that react on a semiconductor surface. This reaction changes how much the sensitive element resists.
When the sensor device heats up and gas touches the semiconductor surface, the molecules first stick to it. They then move across the surface and lose their energy.
Some molecules evaporate, while others break down and stick to the surface. They take electrons from the device. This creates ions that have a negative charge. These ions form a charge layer on the surface.
If the work function is higher than the dissociation energy of the molecules, they release electrons to the device. This makes positively charged ions that stick to the surface. This type of gas sensor works by changes in the capacitance and voltage of MOS diodes. It also detects shifts in the threshold voltage of MOS field-effect transistors.
**Advantages:** Quick response time, good resistance to the environment, and a stable design.
**Disadvantages:** Sensitive to changes in temperature and humidity. It is often used for higher and less common levels of CO2. Readings can be affected by other substances in the air.
4. Catalytic Combustion CO2 Sensors
Catalytic combustion CO2 sensors use a resistor that is coated with a catalyst as their main part. At certain temperatures, flammable gases can catch fire on the surface of the resistor. This is the main idea behind how this sensor works. For this reason, these sensors are also referred to as thermal combustion sensors.
**Advantages:** Precise measurements, quick response time, and a long operational life.
**Disadvantages:** The detection range for certain gases is limited.
**7 Types of CO2 Sensors and Their Applications**
CO2 sensors work in different ways. They also look different and have various functions based on their use. Here are seven types of CO2 sensors made for different uses:
1. **Home CO2 Meters**
Home CO2 meters are small, useful, and easy to carry. They are wireless and multifunctional. These devices check the conditions inside your bedroom.
They track humidity, CO2 levels, and temperature. Their smooth electronic screens give useful information to help improve indoor air quality.
These devices are great for offices that want to boost team productivity. They are cheap, simple to use, and do not require wiring.
2. **Wall-Mounted CO2 Sensors**
These high-quality wall-mounted sensors measure air quality in places with high CO2 levels. This includes schools, offices, hotels, greenhouses, and factories.
They can measure from 0 to 5000 ppm or from 0 to 10,000 ppm. Their waterproof cases make them good for tough places. They last for 5 to 10 years after they are installed.
They have RS485 or analog output. This provides stable signals and accurate readings.
3. **Portable CO2 Detectors**
Portable CO2 detectors are easy to move and use. They can check CO2 levels in many locations. These detectors have rechargeable batteries. They can last for up to 8 hours.
They show readings clearly and have an alarm. The alarm warns users when CO2 levels hit the set limits.
4. **Fixed CO2 Detectors**
Fixed CO2 detectors are made for dangerous places where fire or explosions can happen. They have strong stainless steel designs that are waterproof and dustproof.
And they are set up on site. They allow us to watch data from a distance. This helps lower accidents and keep property safe. These explosion-proof detectors are made for industrial use.
5. **Outdoor CO2 Sensors**
Outdoor sensors are great for long-term CO2 monitoring in outdoor areas. They can handle rain, snow, hot or cold temperatures, and UV rays. Their casings help gas flow. They are waterproof and do not rust.
These sensors have IP68 protection standards. They can work outside all the time. This lets you access data from far away. This makes them a smart choice for tough conditions.
6.All-in-One CO2 Sensors
To fully assess air quality, it’s important to measure several elements at the same time. This should be done without interference. Our all-in-one AQI sensor measures more than CO2.
It can also track temperature, humidity, and air pressure. Additionally, it measures light, CO, NH3, CH4, O2, formaldehyde, TVOC, O3, SO2, NO2, H2, and more.
The fully integrated AQI sensor can monitor up to 11 elements, delivering robust performance in a single device. It simplifies complex monitoring tasks by replacing the need for multiple individual detectors, making environmental analysis more efficient and streamlined.
7.Duct-Type CO2 Sensors
The duct-type sensor is made to measure CO2 levels in ducts or tubes. It has a strong stainless steel probe at the end of a metal pipe.
To install, drill a small hole. Next, place the probe inside the tube to take longer measurements. Its special design helps it work well in tough places while giving accurate readings. The device is easy to use and made to last for long-term use.