mqtt433 python service script to use rtl_433 and a SDR dongle to read Acurite temperature/humidity sensors (or other 433MHz) into JSON and publish to MQTT topic for Homeassistant home automation sensor integration. I did not write the originals of these scripts, merely debugged for my own purposes.
The initially recommended way to get rtl_433 data into mosquitto is as follows:
rtl_433 -F json -U -G | /usr/bin/mosquitto_pub -h [ip address] -u [login] -P [password] -t home/rtl_433 -l
The problem is that the sensors transmit each signal multiple times. With two weather sensors and half a dozen contact sensors the system would get around a dozen messages per minute. In the above command line that means a dozen logins per minute. The system was unstable, mosquitto kept crashing.
Github member packitout did a great job of wrapping the process into a python script that allowed the login to mosquitto to be maintained between messages, this stopped the crashing.
I have taken this one step further. For each sensor I get a signal from I store the value (minus the timestamp) for future comparison. When new data comes in, I compare it against the old data and only send it if it has changed. This buffering not only reduces data flow between the various programs but makes it so that when a new value comes in, it will not be the same value as last time making sifting through logs much less repetitive. With this in place I get approximately 0 to 2 messages a minute with the same sensors mentioned above.
Some devices like motion sensors, smoke detectors and leak sensors might only ever emit one code, so buffering is not desirable. For this I have added a --nocache argument to the command line. Seperate ids of devices not to cache by spaces. If it is not cached, it will always be considered fresh.
e.g. python mqtt433.py --nocache 2345 100001 100030 100700
Many of the same devices above will transmit the code a couple of dozen times in the period of a couple of seconds. If --nocache is used the data will get published to mosquitto as many times as it is received. This may be dozens of times in seconds. To avoid this I have created the --tmpcache parameter which works the same as the nocache parameter except the code does get cached for a couple of seconds, then forgotten. This eliminates most of the repetitious publications to the mosquitto broker.
e.g. python mqtt433.py --tmpcache 2345 100001 100030 100700
A combination is also possible
e.g. python mqtt433.py --nocache 2345 --tmpcache 100001 100030 100700
The data set to mosquitto is optimized too. The script goes through the JSON payload and for each variable determines if something has changed. It then sends out a message just for that variable as follows:
The MQTT Topic begins with "r433/' it then has the id followed by another "/" and then the variable name. For a door contact sensor I have that might look like:
Topic: r433/50643/cmd
Payload: 14
This makes for simple mapping in the home automation application.
this is the python script to run as a service. it requires paho-mqtt (https://pypi.python.org/pypi/paho-mqtt/1.1). Right now it only uses user authentication for the MQTT broker (so put the username and password you want this system to use to connect to the broker into this code) since it is meant to run on the hub machine connecting to the broker with the 1833 port (as opposed to the 8833 port for TLS encrypted traffic of MQTT clients outside the local network).
just used to listen or publish to MQTT topics for debugging.