Monitoring of methane levels is largely driven by the range in concentration of methanegas you are trying to detect. Detection of methane near the lower-explosive-limit (LEL) is obvious since exceeding the LEL can be extremely dangerous. Most of the commercially available solutions focus on this methane concentration level. In this post I want to highlight some of the current options for detection of the LEL that are commercially available.
Let’s say you have a process that is still under development or needs monitoring for safety reasons. And let’s say that you need to know what the level of methane concentration is in this process continuously 7 days a week. And let’s say you need to be able to access the time history of your process, e.g. what was the concentration 3 weeks ago when we had that super cold overnight temperature that forced me to scrape ice off my windshield before I could leave the house for work. In other words, you want to be able to correct and compensate the sensor signal due to large changes in temperature.
The modules in the table below are evaluated against this context. We want minimal measurement uncertainty AND the ability to compensate and correctly adjust for wild temperature swings in case your process or monitoring takes place outdoors or is exposed to large temperature gradients.
Vendor/Brand | Product Link | Sensor Type | Price (USD) | Lead Time | Accuracy | Response Time | Data Output |
Unitense | NDIR | $110 | In-Stock | +/- 6% | < 30 s | UART | |
SGX (Amphenol) | NDIR | $181 | In-Stock | +/- 0.15% | 20 s | UART | |
eLichens | NDIR | $273 | 20 Days | +/- 5% | < 30 s | UART | |
Cubic | NDIR | $275 | In-Stock | +/- 6% | < 25 s | UART | |
Dynament | NDIR | $270 | In-Stock | +/- 2% | < 30 s | UART | |
NevadaNano | MEMS | TBD | TBD | TBD | < 20 s | UART |
I used a combination of asking Claude for recommendations and google searches to compile this list. There were some TDLAS options available but they were either way more expensive or required much larger input voltages than the microcontroller-friendly 3v3 and 5v inputs the sensors in the table require.
I included the MEMS-based NevadaNano sensor in the list since it seems like it could be a competitor to the affordable NDIR types. However, I was not able to find an online source for easy sourcing of their sensor modules. I did reach out to them directly to get more information. It is also important to note that the NevadaNano sensor is not useable in an inert gas environment. I think it requires oxygen for its operation.
The ultimate test for actually buying one of these sensors to evaluate them myself was availability, cost, and potential ease of use. My next step in this evaluation will be to start designing a custom PCB for integrating these sensors into my overall system design. Subscribe to my newsletter and follow along as I evaluate these sensors further! I also frequently provide updates on my Redwood Labs YouTube channel.
