AS7331 always returns the same values

Sensors
1

I’m using the SparkFun Mini Spectral UV Sensor with a ESP32 C3 Super Mini board connected to the normal I2C pins. Sensor power light comes on and when I use your Arduino library with my sketch everything says it is successfully connecting. But when i read UVA and UVB they always have the same values (2.6 and 2.9). When I run your unmodified Basic Oneshot example it does the same thing. It prints this:

UVA:2.66 UVB:2.95 UVC:1.30

I can cover the sensor or put it in bright sunlight and the values never change. What could be the problem?

2

I just hooked up a stock Arduino Uno to GND, 3.3v, SDA (A4) and SCL (A5). Still get the same values: 2.66, 2.95 and 1.3. This is with the supplied Basic_OneShot sketch.

Do I have a bad part?

3

And yes, the power LED is lit on the Mini Spectral UV Sensor board

4

Try using one of the alternate (non-one-shot) modes and see how that goes Arduino Examples - SparkFun Spectral UV Sensor - AS7331 (Qwiic) Hookup Guide

5

Thanks. Now that I’ve added stock Uno into the mix I will try that. Have to wait for a new part though. Since Amazon’s return policy is so generous I’m getting it replaced on the off chance that it’s a bad part. When that comes in I’ll try other examples and I’ll also try to use some of the raw calls to see if this the problem is reading the data or calculating the final values.

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