433,92 Mhz, it’s in the air.
This is one of the frequencies that is used for wireless control of lights, blinds, doorlocks, car doors etc. Weather stations can use it transmit readings from an outdoor sensor to an indoor unit and so do many other devices.
A good piece of software to receive all these transmissions is rtl_433, I’ve written an article about it some time ago. Many protocols are supported and recently the output format has changed. This makes it easier to setup a single cheap receiver and share the received information via MQTT. I’m using the following script:
# A simple script that will receive events from a RTL433 SDR
# Author: Marco Verleun <firstname.lastname@example.org>
# Version 2.0: Adapted for the new output format of rtl_433
# Remove hash on next line for debugging
# Start the listener and enter an endless loop
/usr/local/bin/rtl_433 -F json | while read line
# Log to file if file exists.
# Create file with touch /tmp/rtl_433.log if logging is needed
[ -w /tmp/rtl_433.log ] && echo $line >> rtl_433.log
# Raw message to MQTT
echo $line | /usr/bin/mosquitto_pub -h $MQTT_HOST -i RTL_433 -l -t "RTL_433/Raw"
This will setup your receiver to transmit all the information received and supported in JSON format to your broker. The topic is “RTL_433/Raw”.
A nice tool to process these messages further is nodered.Disclaimer: All information posted is written with the upmost care and valid at the time of writing. Changes in versions can supersede the provided information. Please use your own judgement.