AQM III SCD30 not working - Printable Version

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+---- Thread: AQM III SCD30 not working (/Thread-AQM-III-SCD30-not-working)

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AQM III SCD30 not working - jrichert - 04-08-2021

Hi

I just compiled and setup my AQM with SPS30, SCD30 and BME280.

SPS and BME are showing values, SCD is showing no Temp/HUM or CO2 values.
If I connect only BME280 and SCD30, at least Temp and Hum from SCD is shown, but no CO2.

Now I recompiled to MH-Z19B with BME280 and SPS30 and all is working fine.

Is it possible that both Sensirion are not working together or is the SCD30 broken?

Any ideas?

Many thanks
Jochen

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RE: AQM III SCD30 not working - werk_ag - 04-08-2021

Hi Jochen,

I'm using exactly the same set of sensors, so I can assure they all work together.
Can you post your Config_Options.h file?

Pay attention to the length of the cables used with the BME280 (preferably connect it directly to the PCB) and with the SCD30. Cables must be quite short.
Also check your power supply. While the average consumption is 150mA, when reading sensors, the consumption may exceed 300mA, not all USB ports can deliver such current.

Rgs

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RE: AQM III SCD30 not working - jrichert - 05-08-2021

Hi Rgs

Than the cable length could be the problem. The cables were abt. 30cm long to separate the PCB and sensors into two different housings. I cut it already down to 17cm, but it was still not working.
I think, the config file won't help anymore, as I already changed configuration to MH-Z19B. But the cable for the MH-Z19B is abt. 25 cm long and working...

I'll give it a second try on the second PCB and a Plantower dust sensor, this evening.

I just received an VW ID4 GTX for test drive, this is more important for now ;-)

I'll keep you informed how it's going on..

Cheers
Jochen

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RE: AQM III SCD30 not working - werk_ag - 05-08-2021

Hi Jochen,

Any sensors which use the I2C bus must use very short cables and be placed near the PCB as possible, that isn't an issue, its a design characteristic of the I2C bus, no matter the system.
The MH-Z19B sensor communicates using a serial port not I2C, that's why it can work with cables up to 30cm or even a little more.

As a reference here is a picture of a system using exactly the same set of sensors than you. The SPS30 is under the PCB. Cables are no longer than 10cm.



Rgs.


PS: VW ID4 GTX, nice car

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