Boron 404x and Senseair-brand K30 CO2 sensor: power problem

Hardware
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This is a follow-up to my post yesterday about using the Boron series in an environmental data collection context, specifically using it to run an IoT device that uses a nondispersive infrared, Senseair brand K30 sensor to measure carbon dioxide (CO2) concentration regularly.

what is the max current that can be supplied by the VUSB pin on the Boron 404x? Datasheet says 500mA, but we observed that the K30 (a high-power i2c sensor that consumes 300mA peak) is frequently maxing out (reading the max possible value for the sensor, and not actual ambient CO2 concentration). We tried reducing sampling rate to nominal threshold, but no dice.

has anybody encountered this issue with higher-power I2C sensors when using the 404x?

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How big is the power supply powering the Boron? If it’s a laptop, it will likely default to 500 mA which is not large enough to power both the Boron 404X (500 mA) plus a 300 mA sensor.

If it’s a 2A tablet charger it should work.

There isn’t a regulator between the USB power input and VUSB, it’s connected by a diode, but it will still be limited by the USB power supply.

Another option would to power the Boron with an external 5V power supply connected to VUSB. That would power the sensor directly and the Boron through VUSB instead of the micro USB connector.

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