multiple SCD30 + mux question

Sensors Environmental
1

Hello,

I have a question about the SCD30 temperature, humidity, CO2 sensor SEN-15112.

https://www.sparkfun.com/products/15112

I want to hook up multiple SCD30s but they all have the same I2C address.

I know a solution to this is to use a multiplexer (e.g. SparkFun Qwiic Mux Breakout - 8 Channel (TCA9548A)).

https://www.sparkfun.com/products/16784

What I want to know is if the SCD30 will behave normally if I were to use multiple SCD30s in conjunction with a multiplexer? Will it give accurate measurements each time?

Or will there be trouble because the multiplexer is re-activating each sensor when I programmatically switch ports?

Another question:

How many of these could I theoretically hook up and take measurements with over SCL/SDA since I’ll be powering them all over the arduino’s 5v output. It says their current draw is 19 mA and and I’ve read that an arduino can comfortably supply up to 400mA when it’s powered by a USB. So theoretically, in this configuration, I could technically power 21 of these right? (assuming they all took measurements at the exact same time, which I don’t think would be possible using a multiplexer… but just want to make sure?)

Any help is appreciated. Thank You

2

Hi, thanks for posting.

It should behave normally when being used with the Qwiic Mux Breakout.

I am not entirely sure how many sensors you could use simultaneously, however, I think it should be 12 - 20. I cannot confirm nor deny this without testing. I think resistance and powering might be the biggest issue here and you may require using different i2c lines or other controllers.

Hope this helps.