NRF 24L01 communication fails particularly @ midnight / early morning 1:00AM to 3:30/4:00 AM and resumes Automatically

[ASHWINI SHINDE]

Dear All,

NRF 24L01 communication fails particularly @ midnight / early morning 1:00AM to 3:30/4:00 AM and resumes Automatically. In my project, I have 1 base station and 2 remote stations. Each station has 4 sensors(2 DHT11 + 2 leaf wetness sensor) connected to it. One of the remote stations is set at channel 102 and the other remote station is at channel 107. The steps of communication using nRF24L01+ are as follows:

1. Base station sets its own channel at 102. It calls remote station at 102 by sending ID=102.Remote station at channel 102 responds by sending sensor readings to the base station.
2. Now Base station sets its own channel at 107. It calls remote station at channel 107 by sending ID=107.Remote station at 107 responds by sending sensor readings to the base station.
3. After a delay of 7 minutes this procedure repeats continuously.

I have kept the 2 remote stations in an open terrace. Base station is kept on the same floor inside a room with windows open.

Everything works well during daytime. But during 12:30am/1:30am NRF communication stops and automatically resumes after 3:30am/4:30am. I am not able to figure out the reason behind communication failure. Does external environmental conditions affect this communication? Does the medium affect this communication since I have kept remote staions in a open terrace and base station on the same floor but inside a room with windows open?

[ovrebekk]

2.4GHz signals don't play well with water, so if there is a high level of humidity a this time that could be a factor. What is the approximate distance between the nodes?

Also, I wouldn't recommend using channels above 84. This is outside the ISM band, and could perform worse if the RF design is optimized for the 2400-2485MHz range.