Nimrod Gutman Walks Through Grabbing, Graphing Sensor Data with an RTL-SDR and a Raspberry Pi
Linking an RTL-SDR to a Raspberry Pi, Gutman shows how data from off-the-shelf 433MHz sensors can be captured and streamed to InfluxDB.
Technology enthusiast Nimrod “Guti” Gutman has written up a project that combines an RTL-SDR software-defined radio (SDR) and a Raspberry Pi 4 to read live environmental readings from a low-cost 433.92MHz wireless sensor module.
"I was always interested in the RF world," Gutman explains, "the fact that we are surrounded by an infinite amount of invisible waves that carry information is intriguing. A lot has changed over the years, the technology advanced and today you can easily dive into the electromagnetic realm without fiddling with mountains of equipment and burning your pocket."
Gutman's project begins with analyzing the signal from an unmodified off-the-shelf wireless hygrometer and temperature sensor, using the RTL-SDR receive-only software defined radio dongle and the CubicSDR macOS package. "Let’s get ready to use rtl_433 by looking at the frequency and making sure there are devices there," Gutman writes. "Usually they will transmit information in 30 second bursts, you can change the center frequency to 433.92Mhz and check that you see data."
Once the presence of the device is confirmed, the RTL-SDR is moved across to the Raspberry Pi 4 single-board computer and the rtl_433 package installed. "We’re getting live sensor data, that’s pretty awesome," Gutman notes. "Let’s stream everything to InfluxDB." With the data streaming live to InfluxDB, they can be graphed — with Gutman demonstrating the concept using a range of sensors now linked to his home network.
The full guide is now available on Gutman's website.