The Sensors You’ll Never See

co2 sensor testing

I was looking at a consumer product the other day to test CO2. The sensor inside was small. The product was cool. I was sure our customers would like it. So I sent an email with a link to the product to Ray Hicks, President of CO2Meter and our chief engineer. I got a one sentence reply:

“Know the product, it’s a ------- We tried it, but it’s not stable, I have 10 or 20 on the shelf.”

What you may not realize is that for every OEM gas sensor module we sell there are three more sitting in a dusty bin on a shelf you will never see and we will never sell.

How CO2 Sensors are Discovered

It starts with Ray Hicks, President and Irene Hicks, CEO of CO2Meter, Inc. who travel worldwide to sensor trade shows. Once they find a sensor that meets a need or fills a gap in our product lineup, they will visit the manufacturer’s plant where the sensor is made. If they are satisfied with the quality control of the production process, they will order a batch of sensors for analysis.

How CO2 Sensors are Tested

When sensors arrive at our facility, our in-house engineers spend hundreds of hours testing them for accuracy and repeatability, and testing I/O to verify functionality. If the sensor performs reliably to spec our engineers write code in our free Gaslab® software to make it easy for OEMs to communicate with the sensors during application development.

But we’re not finished testing yet. Depending on the application, some new sensors are given to a select group of electronics experimenters and researchers around the country who integrate them into projects and report back their real-world results. We also follow up closely with "early adopters" who will purchase these new sensors for their expanded feature set. And we monitor and follow up on every return we get from the field.

Throughout this entire process, our engineers exchange emails with the manufacturer’s engineers to ask for low-level documentation, undocumented features, or to ask for changes to make the sensors easier to use. It is not uncommon for us to receive binary code to re-flash an entire batch of sensor’s ROM memory before we make them available to customers.

For example, the most common UART (serial port) configuration in asynchronous mode is 9600/8/N/1. If a sensor doesn’t use this industry standard (some don't), we’ll ask the manufacturer to change it before we offer it to our customers. The same goes for I2C, analog voltage or digital I/O outputs.

In addition to testing by our engineers, we continuously collect customer feedback and sent it back to the manufacturers. This cycle benefits everyone as the sensors continue to evolve and improve.

Only after a sensor passes through this gauntlet do we begin to stock it in quantity to make it available for next day delivery to you.

How CO2 Sensors are Sold

Other companies may offer the same sensor modules online, but they have never actually bench-tested the sensor. Everything they know is printed on the manufacturer’s data sheet. Instead, they pass orders on to the manufacturer, let you wait 4-6 weeks for delivery, and keep the difference between the price paid and their cost as profit.

Because of our intimate knowledge of the sensors we sell, manufacturers worldwide send their customer requests for short-run orders or for technical support to us. We also serve as a liaison between overseas manufacturers and OEM users to make shipping easy and just-in-time delivery dependable. For large-quantity orders, we even negotiate with the manufacturers to get our customers the lowest possible volume pricing.

Why it Matters

All this sensor knowledge helps our customers in three important ways.

  • It makes our customer service team much more knowledgeable about gas sensors when making a recommendation for a project or device.
  • We only use the best sensors available when we design our own products like the CO2 + RH/T Data Logger to test indoor air quality.
  • It gives us very happy customers.

Do We Get it Wrong?

Do we get it wrong? Occasionally yes. Ray tells a story about a CO2 sensor we were very excited about for incubation and live animal applications. The sensor even briefly appeared on our website, although we didn’t put any in the field. Ultimately we couldn’t trust it, so we took it off the website. It wasn’t until later during a visit to the vendor that he discovered the sensor production was being sub-contracted to a “back water” factory with no quality control. It was a huge waste of both time and money, but you can still find that sensor on other websites for sale today.

So the next time you see one of our gas sensor modules on the website or in a newsletter article, I hope you appreciate the fact that it is one of the best.
Posted by CO2 Meter on May 09, 2017.
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