SGP40 TVOC sensor

I intend to get the Pro Kit and install a TVOC sensor. Since SGP30 is being discontinued, has anyone had experience using SGP40 (with a board with the same pinout; VIN, GND, SCL, SDA ) as a drop-in replacement?

Seems like the main difference is that SGP40 reports a VOC Index rather than Total VOC in ppb, as well as a much faster switch-on time of 1h: https://sensirion.com/media/documents/B2035E62/617BDA44/Sensirion_Gas_Sensors_SGP30_SGP40_transition_guide.pdf

Also, has anyone had experience using SGP41 which also measures NOx?

I ordered these and have been pretty happy with them. The pin out is NOT the same and what’s on the Pro kit. The GND and VCC pins are switched. I just use two wires instead of pins to crossover. I am also using EspHome. You are correct that they now report an index (for both NOx and VOC). This document explains the index. In summary: both indexes are 1-500 where 100 is average/normal for VOC and 1 is normal for NOx.

Edit: To note, the Airgradient dashboard reports VOC in ppb so it will not be accurate with the SGP41. It will report the index value instead.

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@phillipppp clever solution for the pins!

We are currently developing a small SGP40 module that would work with the DIY kit pins and we will have that available in our DIY shop in a few weeks.

That model will also then have no pull-up resistors so when people build the kit they won’t need to manually remove them.

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Any updates on the custom SGP40 sensor?

I am anxious for this as well. Will pick up for the diy pro presoldered kit that just came in.

No specific update, except that it will definitely come. I am still waiting for one of the modules here to arrive.

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