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Problem with Optional CO2 sensor - Printable Version

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+---- Thread: Problem with Optional CO2 sensor (/thread-2378.html)


Problem with Optional CO2 sensor - sv2bzq - 10-02-2026

Hi. 
After a long time and a lot of reading I managed to get the AQM-III working.
But the only problem I have is with the Sensirion SCD30, it worked for 2 reboots then stopped and shows me 0.
I have Arduino IDE 1.8.19 / ESP32 2.0.3 and firmware 6.1_b013.
I would appreciate any help. Is there a chance that the Sensor is broken?

George.

RE: Problem with Optional CO2 sensor - werk_ag - 12-02-2026

Hi,

Please try to enable the PRINT_DEBUG_CO2 function on the Config_Options.h

Change this (line 237):

Code:
//#define PRINT_DEBUG_CO2

to

Code:
#define PRINT_DEBUG_CO2

compile the code and upload. Keep the device connect with and USB cable, open the serial monitor and watch what comes out.

RE: Problem with Optional CO2 sensor - sv2bzq - 16-02-2026

Hello, I did what you told me and I got this indication.

Code:
14:09:28.883 ->
14:09:28.883 -> CO2 RAW: 0
14:09:28.883 -> CO2 Instant: 0
14:09:28.883 ->
14:09:28.883 -> CO2 RAW: 0
14:09:28.883 -> CO2 Instant: 0
14:09:28.883 ->
14:09:28.883 -> CO2 RAW: 0
14:09:28.883 -> CO2 Instant: 0
14:09:28.883 ->
14:09:28.883 -> CO2 RAW: 0
14:09:28.883 -> CO2 Instant: 0
14:09:28.883 ->
14:09:28.883 -> CO2 RAW: 0
14:09:28.883 -> CO2 Instant: 0

Thanks for the time.
George.

RE: Problem with Optional CO2 sensor - werk_ag - 02-03-2026

Hello George,

Sorry for the late reply.
Apparently the sensor is replying to queries, but returning only 0. I'm not sure but it's possible that the sensor isn't working properly.

Rgs.
Werk_AG