Temperature & Humidity Sensor

I’ve finally gone round to properly connecting my DHT22 sensor to my Raspberry Pi.
It’s actually been working fine for about 2 week, but as it was sitting on the breadboard on top of the Pi, the readings were not exactly accurate: it’s pretty warm and dry up there.
So today I moved the sensor outside to get real readings.

I’ve based my setup thanks to a tutorial on Adafruit. You can get it HERE

I’ve done a few changes though:

  • Based on the temperature and relative humidity readings, I’m calculating the dew point / frost point. The formula I used is this one:

    Dew point equation

    Dew point equation – Click for source website

  • I’m updating the readings to my SQL Database so I can use then on any page.
  • I’ve set up the readings to get added to an online Google spreadsheet only once per hour. The idea is to keep recording for as long as I can and then get some yearly trends. You can access the spreadsheet HERE