- read the sensors once each minute
- write the results to a CSV file
- email the CSV file once per day so that we can graph the results and look at trends, and
- email if a sensor is over a set temperature threshold for a set period of time
This has worked long term, and I'm fairly satisfied with the results. The one problem that I've run into is that if I were to add another sensor to this RPi it causes several of the sensors to disappear.
My question is related to this problem. I want to add an arbitrary number of additional sensors, but I'm not sure whether the problem is the overall capacitance of the run, or whether there's too much voltage drop in the Vin line to the sensors. I'm powering the entire bus off of the RPi 3V3 rail.
My solution so far was to just get another RPi in order to host the additional sensors. But because of the size of the facility, if we wanted to monitor even more locations this could get to be a silly number of Pi's. I was thinking of trying to externally power the bus instead of feeding it from the RPI, but then how do I properly do this without causing problems to the Pi?
Any ideas would be appreciated. Thanks!