Temperature monitor with RTL-SDR

So, after taking its time travelling the eastern oceans, my RTL2832U based DVB dongle finally arrived this week! Check the previous post for some background on what I have in mind for it 😉

In the short time with it, I only had partial success picking up the energy monitor sensor values. Some signal seems to picked up but can’t decode and ectract the values just yet. But, I did managed to have quite some fun with the RF temperature sensors I have lying around!

Here’s a nice shot of a little page I’ve put up, showing the temperature history at my balcony:

History of outside temperature at my balcony
History of outside temperature at my balcony

Here’s the basic architecture of the setup:

  • The DVB dongle is plugged into a RasperryPi
  • The Raspi is connected to my LAN and runs the rtl_433 utility, modified by me to be able to decode the values of each sensor
  • When picked up, the temperature value gets submitted to a Google form, storing the value in a Google Sheet
  • In the Sheet, the history of temperatures is displayed on a chart

Bonus action: upon submitting a new value, a script in the Sheet sends an email to ifttt.com, activating a recipe that tweets the value! Check out the Twitter feed! The feed is rate-limited to roughly 1 tweet every 30mins.

I’ll go into more detail in some future posts, stay tuned 😉