METER ATMOS 41 GEN 2 tested

Back in late 2024, METER Group revamped their ATMOS 41 weather station SDI-12 sensor and unveiled a GEN 2 of the same weather station. I was able to get a hold of one thanks to a client. After some initial struggle with it, I realized that I needed to update my firmware in a couple of places to handle this sensor.

First, it responds to polling faster so I have to remove one of the commands that may momentarily block SDI-12 receiving right after sending out a command. This used to be no problem at all but this new sensor responds so fast that the first few characters got garbled if I block receiving even momentarily.

Second, it has some unusually long responses in some of its non-SDI-12-compliant command responses, as long as 141 characters. This is much longer than the maximal allowed 76 characters by the standard. So I bumped up the buffer size to be able to swoop up all of its responses.

After some initial tests, I was able to confirm that the updated firmware version 1.5.11 (15B) works with this sensor. I did this in the spring but haven’t got around to post an update yet. If you need to use this sensor, you can update your firmware to 15B. The instructions and the new firmware are in the adapter’s main page.