Welcome back to part 3 already with DVB-T Fun with a Raspberry PI. In this part I will show you how you can profit from receiving all the data of your neighbors fancy wireless weather station data and use it for your own benefits.
Weatherstations with wireless sensors are very common and cheap now-a-days. Prices vary from 80 euro to a few hundred euros. What most of them have in common is the use of the LPD433 (Low Power Device 433 MHz) or unlicensed ISM band/SRD bandfrequency to transmit the data on air. (Among with wireless doorbells, cheap wireless alarms, car key-locks e.t.c…)
The maximum transmission power for these devices is 10mW max. This will cause you will be receiving only weather stations that are in your direct vicinity (depending on your antenna set-up of course)
In order to decode these signals I will have to redirect you to part 1 where the basic setup for the basic setup of RTL_SDR. If you have this working, the following program will work too as it is based on the same code.
We will use rtl_433, which turns your Realtek RTL2832 based DVB dongle into a 433.92MHz generic data receiver.
git clone https://github.com/merbanan/rtl_433.git cd rtl-433/ mkdir build cd build cmake ../ make
Now… lets start the fun, and start the program (which will be located in /rtl_433/build/src)
pi@srv-rasp-01 ~/rtl_433/build/src $ ./rtl_433 -p 24 Registering protocol Rubicson Temperature Sensor Registering protocol Prologue Temperature Sensor Registering protocol Silvercrest Remote Control Registering protocol ELV EM 1000 Registering protocol ELV WS 2000 Registering protocol Waveman Switch Transmitter Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000001 Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Found Rafael Micro R820T tuner Exact sample rate is: 250000.000414 Hz Sample rate set to 250000. Sample rate decimation set to 0. 250000->250000 Bit detection level set to 10000. Tuner gain set to Auto. Reading samples in async mode... Tuned to 433920000 Hz. Sensor temperature event: protocol = Rubicson/Auriol rid = ac temp = 5.2 ac 80 34 f6 50
And there is the first weather station. 5.2 degrees Celsius. Good to know 🙂 .. There are many more options to explore (you can use the -a option to analyze the signal) and you probably will receive some wireless doorbells, energy switches , e.t.c. so hopefully this will inspire you to do something nice with it.
Good luck with receiving!