Tagged: temperature sensor

Using CubicSDR, rtl_433, MQTT and Telegraf to Stream Live Data to InfluxDB

Nimrod makes his own sourdough and wanted a way to track the temperature and humidity of the bread making environment. To do this he's set up a system involving rtl_433 on a Raspberry Pi which live streams all of his home temperature/humidity sensor data into InfluxDB. The program rtl_433 is software for the RTL-SDR that allows users to receive data from many different brands of home weather/temperature sensors, as well as many other wireless ISM band devices. InfluxDB is a type of database that specializes in storing and displaying time series data from sources like sensors.

The chain of data starts with rtl_433 which collects the temperature sensor data via an RTL-SDR. The output of rtl_433 is sent to Mosquitto, an MQTT messaging protocol server. A program called Telegraf then subscribes to the MQTT queue, and parses and transmits the metrics to InfluxDB. InfluxDB finally records the data, and provides graphical plots. 

Nimrod's post is a full tutorial showing how to download and set up each of the programs used in the system, and how to view the data collected with InfluxDBs graphing system.

RTL_433 temperature graphs via InfluxDB
RTL_433 temperature graphs via InfluxDB

Blindly Reverse Engineering a Wireless Protocol

Hackaday has brought to attention a document written by a Rory O’Hare which discusses the journey Rory took in trying a decode an unknown 433 MHz signal received from his SDR dongle.

If you are interested in manually decoding some unknown signals you may be interested in this write up as it discusses his entire journey including the failures he encountered along the way. Basically he records some packets using his SDR dongle, works out their bit patterns manually and then attempts to find correlations between the packets in an attempt to discover their structure. In the end his efforts are successful as he discovers that he is receiving a temperature sensor and is able to decode the temperature readings.

Discovering Correlations in the Received Packets
Discovering Correlations in the Received Packets

Decoding a Weather Temperature Sensor with the RTL-SDR and GNU Radio

Over on YouTube user MrCircuitMatt has uploaded two videos on how he was able to decode a temperature weather sensor using an RTL-SDR and GNU Radio. His videos go through the GNU Radio technical steps as well as the signal encoding theory he used to decode the temperature.

Using RTL-SDR to read temperature from outdoor sensor, part 1
Using RTL-SDR to read temperature from outdoor sensor, part 2