Day: January 2, 2025

  • DHT22 is logging

    DHT22 is logging

    For my indoor garden I wanted to monitor the temperature inside and outside the tent. It is in the basement, which I don’t think ever gets above 70 or below 50, but to control the plant’s cycles I need to control light and temp. The light came with an App so I just needed to get temp data into my database. Here is the code I’m using at the moment. I’d also like to log outside temperature data, but I haven’t figured that out yet. I’m think there has got to be an API for the NWS that I can put in a zip code and get the temp and humidity. Here is the code, and some notes.

    We need to get some libraries and connect to the sensors.

    I have two functions. One to get the data from the sensors, and one to insert the data into the database.

    sensors
    insert data

    Where the magic happens

    and some cleanup

    So I calculated the space needed by putting 10 readings in the db, and if the average holds(which it should only go down) I will use about 840 MB a year to get a reading every minute, which I don’t really think I would need, so I’ll probably lower it to once an hour maybe later.

    1638 average row size, in bytes(i think)

    so 1.6kb a reading.

    60 minutes * 24 hours * 1.6kb = 2,304kb a day

    2.3MB * 365 = 839.5MB a year