Here is what is happening. I have a 16 bit A/D (ADS1115) converter that is connected to a differential pressure sensor that's not connected. So it should be recording just ambient air turbulence, a breeze coming into the window, or someone walking by.
But I see something that I can't explain. The recorded signal has much more noise between around 6:30pm and 7:15am. And the signal level abruptly drops/rises roughly 0.5mV around those times.
Temperature is stable. AC voltage is stable. Barometric pressure is stable. I can't pinpoint any external factor that would line up with those times. And then I realized that those are exactly the sunset and sunrise times. But with the A/D converter and the sensor are in the basement. With 2 floors of living space above it. How could the sun come into play here?
I could collects data for a few months and see if it shifts with the sun. But I'm not even sure I'm on the right path here. Ideas?
The converter and logger are powered through 2 switch mode power supplies in series, so it should be well insulated from the power grid. There are no solar panels on the house or in the vicinity.
But I see something that I can't explain. The recorded signal has much more noise between around 6:30pm and 7:15am. And the signal level abruptly drops/rises roughly 0.5mV around those times.
Temperature is stable. AC voltage is stable. Barometric pressure is stable. I can't pinpoint any external factor that would line up with those times. And then I realized that those are exactly the sunset and sunrise times. But with the A/D converter and the sensor are in the basement. With 2 floors of living space above it. How could the sun come into play here?
I could collects data for a few months and see if it shifts with the sun. But I'm not even sure I'm on the right path here. Ideas?
The converter and logger are powered through 2 switch mode power supplies in series, so it should be well insulated from the power grid. There are no solar panels on the house or in the vicinity.