SCD41 Co2 sensor, power supply question

Qwiic System
1

I have been experimenting with SCD41 for a while now it kept giving me weird values and/or stopped working out of nowhere.

now I find out that it is because the SCD41 does measurements every 4-5 seconds and therefore pulls the current in a periodic manner. the 3.3V supply from teensy 4.0 I use could not keep up and caused a brownout effect.

so I tried to change it to an external source which is some protoboard power regulator(also from sparkfun, the one with barrel jack selectable 5,3.3V output) but it too could not keep up with the change. from my measurement, the voltage dropped to 3.1V even though the supply should be able to supply up to 800mA.

my solution now is to use a bench supply adjusted to 3.6V so it is not dropped below 3.3V.

I am looking to use an adjustable buck converter to do this, but is it a good practice? what should I do?

Side note from SCD41: it is working fine connected to Teensy4.0 via qwiic system can read everything just fine so I did not think much about it BUT it will stop working, and no fresh data after some time (sometimes minutes, sometimes hours), CO2 ppm output is out of range like 40 or 1000+ . if you have this symptom probably the same power supply problem.

2

The adjustable buck should be fine. You might want to add a 100 to 1000 uF capacitor across the power leads to the sensor to provide an extra reserve of power when it takes a measurement.

3

liaifat85:
Adjusting the power supply to 3.6V should not cause a problem. The allowable supply voltage of SCD41 is 2.4-5.5V.

Thanks!

4

YellowDog:
The adjustable buck should be fine. You might want to add a 100 to 1000 uF capacitor across the power leads to the sensor to provide an extra reserve of power when it takes a measurement.

Thank you!