Chart data have strange "regular" difference

I am using Cayenne in different projects on different boards and quite happy - works well. When downloading photocell data from chart, I found strange, very regular (every day at 2,00 am) difference in data, when value for that specific hour drops about 50%:

any idea?

I have the same issue with cheap DHT11 sensor. Maybe it is from the sensor? How do you wire it? Do use resistor for that photo-resistor ?

Are you using a Pi or Arduino?

Arduino (NodeMCU)

I am using onboard photocell:

The only suggestion I have is hook up the Arduino to a computer and let it run with the serial monitor open to see what is happening at 2:00

Hello @adam, this is good suggestion! I will try with mine cheap DHT11 as well :slight_smile: