This fork (mdickers47/rtldavis) is a fork of [http://github.com/lheijst/rtldavis]. The way the lheijst and bemasher versions work is that they implement the Davis frequency hopping, demodulate the packets, and dump them to the log file as hex bytes. Something else has to decode the messages to create weather data. Luc wrote https://github.com/lheijst/weewx-rtldavis which is in Python and operates as a weewx driver to update a weewx database.
My change is that I have adapted the packet parsing code from
weewx-rtldavis into the go binary. You can now write the decoded weather
data to stdout with the option -g -. It will be written as one data
point per line, where each data point is three columns, which are metric
name, value, and UNIX timestamp:
wx.davis.windspeed_raw 0 1703133526
wx.davis.winddir 143.74 1703133526
wx.davis.windspeed 0.00 1703133526
wx.davis.temp 50.20 1703133526
This is the Graphite/Carbon "line receiver" format. If you specify
-g server:udpport, this rtldavis binary will send the data directly
to Graphite via UDP packets.
Beware that I have only implemented the parsing for the Vantage Vue
ISS sensor package with the 0.2 inch rain bucket, because that is what
I have. If the -g option is used with a different weather station,
it will be wrong.
- 2023-12-19 M. Dickerson
From here on is the README from lheijst/rtldavis.
This repository is a fork of https://github.com/bemasher/rtldavis for use with custom receiver modules. It has been modified in numerous ways.
- Added EU frequencies
- Handling of more than one concurrent transmitters.
- Output format is changed for use with the weewx-rtldavis driver which does the data parsing.
sudo apt-get install golang git cmake librtlsdr-dev
Next, you need to add some udev rules to make the dongle available for the non-root users. First you want to find the vendor id and product id for your dongle. The way I did this was to run:
lsusb
The last line was the Realtek dongle: Bus 001 Device 008: ID 0bda:2838 Realtek Semiconductor Corp. Bus 001 Device 005: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T
The important parts are "0bda" (the vendor id) and "2838" (the product id).
Create a new file as root named /etc/udev/rules.d/20.rtlsdr.rules that contains the following line: nano /etc/udev/rules.d/20.rtlsdr.rules SUBSYSTEM=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="2838", GROUP="adm", MODE="0666", SYMLINK+="rtl_sdr"
With the vendor and product ids for your particular dongle. This should make the dongle accessible to any user in the adm group. and add a /dev/rtl_sdr symlink when the dongle is attached.
cd /home/pi
git clone https://github.com/steve-m/librtlsdr.git
cd librtlsdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON
make
sudo make install
sudo ldconfig
sudo nano ~/.profile
add at the end of the file:
export GOROOT=/usr/lib/go
export GOPATH=$HOME/work
export PATH=$PATH:$GOROOT/bin:$GOPATH/bin
source ~/.profile
cd /home/pi
go get -v github.com/lheijst/rtldavis
cd $GOPATH/src/github.com/lheijst/rtldavis
git submodule init
git submodule update
go install -v .
$GOPATH/bin/rtldavis
Available command-line flags are as follows:
Usage of rtldavis:
-tr [transmitters]
code of the stations to listen for:
tr1=1 tr2=2 tr3=4 tr4=8 tr5=16 tr6=32 tr7=64 tr8=128
or the Davis syntax (first transmitter ID has value 0):
ID 0=1 ID 1=2 ID 2=4 ID 3=8 ID 4=16 ID 5=32 ID 6=64 ID 7=128
When two or more transmitters are combined, add the numbers.
Example: ID0 and ID2 combined is 1 + 4 => -tr 5
Default = -tr 1 (ID 0)
-tf [tranceiver frequencies]
EU or US
Default = -tf EU
-ex [extra loop_delay in ms]
In case a lot of messages are missed we might try to use the -ex parameter, like -ex 200
Note: A negative value will probably lead to message loss
Default = -ex 0
-fc [frequency correction in Hz for all channels]
Default = -fc 0
-ppm [frequency correction of rtl dongle in ppm]
Default = -ppm 0
-maxmissed [max missed-packets-in-a-row before new init]
Normally you should set this parameter to 4 (-maxmissed 4).
During testing of new hardware it may be handy (for US equipment) to leave the default value of 51.
The program hops along all channels and present information about each individual channel.
Default = -maxmissed 51
-u [log undefined signals]
The program can pick up (i.e. reveive) messages from undefined transmitters, e.g. from a weather
station near-by. De messages are discarded, but you may want to see on which channels they are
received and how many.
Default = -u false
The source of this project is licensed under GPL v3.0. According to http://choosealicense.com/licenses/gpl-3.0/ you may:
- Disclose Source: Source code must be made available when distributing the software. In the case of LGPL and OSL 3.0, the source for the library (and not the entire program) must be made available.
- License and copyright notice: Include a copy of the license and copyright notice with the code.
- State Changes: Indicate significant changes made to the code.
- Commercial Use: This software and derivatives may be used for commercial purposes.
- Distribution: You may distribute this software.
- Modification: This software may be modified.
- Patent Use: This license provides an express grant of patent rights from the contributor to the recipient.
- Private Use: You may use and modify the software without distributing it.
- Hold Liable: Software is provided without warranty and the software author/license owner cannot be held liable for damages.
If you have any general questions or feedback leave a comment below. For bugs, feature suggestions and anything directly relating to the program itself, submit an issue.