https://github.com/ThomasHabets/sparslog
Log power meter data from an IKEA Sparsnäs, by sniffing the radio communication from the sensor to the display.
The communication is one-way, so once you start logging you'll no longer need the display. Unless you like it, of course.
An RTL SDR dongle. Any one will do. This is hardly a demanding protocol.
Of course the better the SDR you have, the more distance and noise you'll be able to handle.
The packets are digital, so if the CRC is correct, then the data is very likely correct.
You'll also need the serial number of your transmitter. It's under the batteries in the device that attaches to the electricity meter.
This project is written in Rust, and doesn't yet have support for any software defined radio. So there's a GNURadio graph that just takes the data and shoves it out over TCP.
There's a version with and without a GUI, in the gr/ directory.
They both listen to TCP port 2000, which the Rust tool will connect
to.
It's easiest to open gr/source_gui.grc in gnuradio-companion, and
pressing play.
Where 123456 is the serial number of your transmitter:
$ cargo build --release
$ ./target/release/sparslog -s 123456 -c 127.0.0.1:2000
It'll print stuff, and log to sparslog.csv.
The format is
timestamp,sequence_number,watts,kwh,battery_status,CRC_status