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In the latest update of app-domoticz, available as a paid app in the ClearOS marketplace, there is now support for using a RTL2832 based DVB-T USB dongle together with Domoticz. It will use the TV dongle as a software defined radio, and receive data from just about any temp, humidity, wind speed and pressure sensor operating at 433 MHzr that you may have in your home. Depending on your antenna and the location, the range can be up to 100 meters or so. Most(?) cheap wireless temperature and weather stations, like the ones from Oregon Scientific etc, operate at 433 MHz unencrypted and can therefore be detected with this setup. Depending on your needs this can be very helpful to include in your home automation project when designing rules that should take weather data into consideration.

What you need:
- Domoticz from the ClearOS marketplace running on a physical computer at your location
- RTL-2832 based USB dongle. You can find cheap ones from USD 10, but I would recommend RTL-SDR Blog V3 which cost around USD 20.
- Antenna (typically for 433 MHz, but there are sensors operating at other frequncies too such as 866 MHz). Try to get a bundled antenna with the USB stick but any cheap antenna (for the right ferquency) works, or in worst case just a insulated wire 16 centimeters long connected to the center pin of the antenna connector (for 433 MHz)

How to use: IMPORTANT: do not install the USB stick before step 2.
1. First in ClearOS webinterface, navigate to Server -> Applications -> Domoticz Home Automation
2. Edit the configuration page and make sure "Enable RTL_SDR" = "true" , press save
3. Now you can insert the RTL2832 based USB dongle into your computer. NOTE: If you inserted the USB-dongle before setting "Enable RTL_SDR" = "true" then do NOT remove it when your machine is running, as it is then using the built in Linux drivers for the TV receiver. Removing it in that state may cause kernel panic... Instead power-off your computer and then remove it.
4.Open a window to Domoticz own webinterface -> go to hardware and add your USB stick. Scroll down to "Rtl433 RTL-SDR receiver" in the list of hardware and give it a name. If you are going to use it for 433 MHz you do not need to enter any additional parameters.
5. Within a minute or two you should see new devices pop up in the device tab. The signal strength (0-11) gives you an indication of how good the reception is. 4 is "OK", higher is better.

PLEASE NOTE: depending on your location, you might pick up sensors belonging to your neighbours or tire pressure sensors from cars driving by. Please check laws and regulations in your country to be sure that you only do legal stuff.

6. In the device tab include the sensors that you are interested in and they can then be shown on the dashboard (See example pictures) or used in your house automation rules.

Welcome to the world of software defined radio and house automation
Wednesday, June 10 2020, 08:11 PM
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