Despite the name, CO2Meter provides more than just carbon dioxide sensors and, instead, can provide full gas sensing solutions to their customers.
AZoSensors spoke to Ray Hicks, the President of CO2Meter, Inc. about the state-of-the-art oxygen sensors they offer, and how over a decade in the business means they can guide their customers to the best tools to meet their gas sensing needs.
How have your 25% oxygen sensors been designed for use in different environments?
Our sensors have been designed so they can easily connect to whichever device that you would like it to talk to. Some applications only require the sensor to connect to an interface board, whereas others have a series of intelligent boards for the data to feed into.
For the sensor to function correctly a zero point must be specified by an external piece of software. We can provide the intelligent board so the sensor can feed information to our GasLab software. This allows the gas span to be determined and temperature compensation to be accounted for. Periodic temperature measurements, and the recording of calibration temperatures, are important in industries such as biotech, where the gas concentration and temperature during processes such as fermentation or inoculation must remain stable.
Intelligent Oxygen Sensor
What other measurements are your oxygen sensors capable of?
In addition to gas concentration our sensors also measure temperature, pressure and humidity. These are three factors that all influence gas measurement and we provide compensation for each of these. For example, oxygen is extremely hydroscopic so the relative humidity (RH) has a strong influence on oxygen measurements.
To make sure our sensors are as versatile as possible we have made measurement compensation optional. If someone wants to use the device as an intelligent sensor they can use RS-485 or an analog voltage to measure the target gas with compensation. All they have to do is plug the sensor in and it starts working for them.
We also provide for customers who are working with more complex systems, which have external compensation. In these instances, they don’t need our compensation but instead use the data to confirm their own. We can provide both the compensated value and the raw value.
How do you communicate with the oxygen sensor?
Our intelligent boards can easily connect to any other device using industry standard I/O. One-way communication is the easy part. The bigger challenge is two-way communication to calibrate the sensor.
For the most accurate sensor calibration, you need a zero point and a known gas level to create a virtual graph in the sensor’s on-board memory. This is referred to as span calibration. It can be done in code, or you can use our GasLab™ software. The software enables the calibration results to be saved back to the sensor so it can be used stand-alone in the field.
Periodic temperature measurements, and the recording of calibration temperature is especially important in industries like biotech, where the gas concentration and temperature during processes such as fermentation or inoculation must remain stable over time.
Gas sensing with regular temperature calibration is essential for temperature-sensitive applications such as incubation in the biotech industry. Shutterstock | unoL
How do you deliver all of this data to your customers?
You can talk to it with any micro controller out there. Our sensors all have well-documented protocols to interface to common devices such as Raspberry Pi or Arduino. We also provide our own processing software, GasLab.
Our sensors can also be connected in arrays which then communicate with each other which allows them to be used in multi-gas sensing applications. So say you have to measure both oxygen and carbon dioxide for your application, you can string an O2 and CO2 sensor together and talk to all of them simultaneously using GasLab.
How do your fluorescence and electrochemical oxygen sensors differ?
The two different sensors we use to measure oxygen both have strengths depending on the application.
The fluorescing sensors we utilize from SST Sensing in Scotland use the principle of fluorescence quenching by oxygen with UV light. While this technology results in a longer-lasting sensor, they tend to only work up to about 25% oxygen by volume in the air. At greater pressures, more quenching occurs which can result in erroneous measurements. However, we've been working with new analytes with higher dynamic ranges, which should allow measurement at higher concentrations.
The electrochemical sensors we utilize are designed for use in flow applications. The strengths and weaknesses of EC sensors are well understood; these are also affected by partial pressure, and that's why our intelligent boards include barometric pressure compensation. This means that if you put the sensor in a pressurised vessel where you want to make a measurement, it will measure the pressure inside the sensor as well as in the surrounding atmosphere. This allows us to compensate for pressure when determining the actual oxygen level.
What different sensors do you provide for use in multi-gas sensing arrays?
We have a wide range of electrochemical sensors for CO2 which measure from 0 to 100%. Beyond 100% we can accurately sense the gas at high pressures. In terms of oxygen sensors we have UV Flux sensors, NDIR and fuel cell based technology for 100% measurement.
We also have a number of different sensors for hydrogen, some of which can even be tweaked to measure gases such as methane (CH4).
How does your smart LED technology work?
The smart LED sensors we work with were developed by Gas Sensing Solutions in Scotland. It is a 20Hz CO2 sensor, which means it takes a reading 20 times a second. The signal is so sensitive that it allows very delicate measurements to be taken, such as those required for capnography (the measurement of exhaled carbon dioxide). A lot of our carbon dioxide sensors that use smart LED technology are used in medical instrumentation or associated university research.
The smart LED technology also has another interesting feature. Because of its high sensitivity, we’ve found that when combined with a second sensor, it can be used to measure methane in real-time.
During testing in the lab we found that by combining a low concentration smart LED sensor (2,000 ppm) with a sensor that is monoscopic to carbon dioxide (only detects CO2) the two values can be compared. Since the smart LED sensor also responds to the methane, calculating the difference allows you to determine the methane concentration in real-time. As an example, this technology could be installed in drones flying over fracking areas to accurately measure methane leaks from the ground.
This is just one example of some of the truly innovative gas sensing problems we’ve helped our customers solve. We’re constantly testing the sensors that we distribute and pushing them to their limits to make sure that we’re providing our customers with the best possible solutions to their problems. Many sensors in the market don’t work as promised. We end up discarding as many sensors as we list on our website as a result!
As part of our testing of new sensors, we validate the manufacturer’s specifications of all of the sensors we distribute and determine how far they can be pushed before giving erroneous results. At the same time, we determine what the optimum duty cycle temperature is, how much poisoning it can withstand, and what other gases interfere with the sensor. This helps us to better recommend a particular technology depending on our customer’s needs.
Who do you think benefits most from CO2 Meter?
It’s difficult to say as all our customers benefit from our expertise. We work across the board with customers from academia to government to industry.
Universities are where all the groundwork goes into research. We help researchers find the best sensor for their research and advise them on different components for their full systems. We also work with industries like gas safety, medical and biotechnology, agriculture and green technology such as algae and biofuel.
However, my personal passion is working with kids in science fair projects. As I get older, I enjoy seeing the next generation trying to solve applied science problems
The biofuel industry is a rapidly growing sector that requires bespoke multi-gas sensing systems. Shutterstock | Kletr
How do you help your customers navigate through the gas sensing landscape?
The gas sensing landscape is constantly growing and changing. Every few months I read about a new gas-sensing technology, so I can imagine what it’s like for people who don’t do this for a living. We find that our customers often need some guidance, but we’re happy to help. In most cases, we can guide each customer to the best sensor for their application, and more importantly, using our experience, we can help our customers cut their development time.
We answer all the customers questions. We are the people that implement this technology on a continuous basis. We understand the software, the hardware, and the physics behind the sensing. We can help whether if the technology is spectral, electrochemical, or a chemical reaction. We've got all this knowledge in one spot so when a customer approaches us with a problem we already know what they are looking for.
Where can our readers to find out more about CO2 meter?
The best place to start is our website. We have data sheets, manuals and application notes for everything we offer, and everything is in stock for next-day delivery.
Of course, many people aren’t even sure what they need. That’s why we have a full team of experienced sales engineers ready to take calls or answer emails.
About Ray Hicks
Ray Hicks has combined his passion for applied science and business for over three decades to create companies in the manufacturing, optics, digital imaging and gas detection industries.
In addition to his role as a serial entrepreneur, Ray has received 70 United States patents, many of which continue to pay royalties today.
Disclaimer: The views expressed here are those of the interviewee and do not necessarily represent the views of AZoM.com Limited (T/A) AZoNetwork, the owner and operator of this website. This disclaimer forms part of the Terms and Conditions of use of this website.