Decrypter and proxy for Luxembourgish "Smarty" meters

This piece of code acts as a "proxy" between the Luxembourgish "Smarty" meters and existing open source software that analyse DSMR telegrams. E.g. dsmr_parser.

I run this on a Raspberry Pi Zero W that I have connected to my "Smarty" meter using a serial-to-USB cable.

Before you start

• Ask you energy provider for your decryption key. This might take a few days. You might want to request from LuxMetering the activation of the full read-out on your smart-meter if you want to get instant voltage/current readings per phase.
• You need a cable to connect your Raspberry Pi (or whatever else you want to use) to the "P1 port" of your smart meter. Those cables are available under different names: "DSMR cable", "P1 cable" or "slimme meter kabel" (which is Dutch for "smart meter cable").
• You need to install the "cryptography" and "serial" libraries for Python. Ubuntu/Debian: sudo apt-get install python3-cryptography python3-serial
• You might need to install "socat" for the examples below. Ubuntu/Debian: sudo apt-get install socat

Test if everything works

• Run the following on the command line and watch the telegrams appear on screen: python3 decrypt.py KEY (with "KEY" being your decryption key)
• If the serial-to-usb cable is not accessible under /dev/ttyUSB0, you can use the "--serial-input-port" argument to specify which path to read from.
• Push CTRL+C to exit

To connect your smart meter to dsmr_parser (or a Home Assistant instance) that runs remotely

Start socat to get a virtual serial port that is forwarded to a TCP connection on port 2001. Please be aware that this way, the data from your smart meter is available unencrypted on your network!

socat -d -d pty,raw,echo=0 TCP-LISTEN:2001,reuseaddr

The output should look as follows.

2018/04/13 20:30:00 socat[1301] N PTY is /dev/pts/2
2018/04/13 20:30:00 socat[1301] N listening on AF=2 0.0.0.0:2001
(...)

Using the given port name, you can now start the proxy with the "--serial-output-port" argument (with the port name from the previous output).

python3 decrypt.py KEY --serial-output-port=/dev/pts/2

You can now configure dsmr_parser (or your Home Assistant instance) to use a TCP connection to the current device on port 2001.

To connect your smart meter to dsmr_reader, dsmr_parser (or a Home Assistant instance) that runs on the same machine

Start socat to get a virtual serial port that is connected to a second virtual serial port.

socat -d -d pty,raw,echo=0 pty,raw,echo=0

The output should look as follows.

2018/04/13 20:30:00 socat[1301] N PTY is /dev/pts/2
2018/04/13 20:30:00 socat[1301] N PTY is /dev/pts/3
(...)

Using the given port name, you can now start the proxy with the "--serial-output-port" argument (with the first port name from the previous output).

python3 decrypt.py KEY --serial-output-port=/dev/pts/2

You can now configure dsmr_reader, dsmr_parser (or your Home Assistant instance) to connect to the second port from the previous output (in this example /dev/pts/3).

Make everything start up automatically

There are different ways to achieve this. One of the easiest is to install "supervisord":

sudo apt-get install supervisor

Then create a custom configuration:

sudo nano /etc/supervisor/conf.d/smarty_dsmr_proxy.conf

My configuration looks like this. Don't forget to use your individual decryption key. To cope with the changing pts numbers, it is easiest to use the "link=" option of socat to create a symbolic name with a fixed name (if you want this link in /dev, socat will have to run as root, and you may need to use the "group=" and "mode=" options of socat so that the proxy can still write on the pts). If you use a second pts as local end point, you can use the same option on the second 'pty' block to provide a fixed name for this as well:

[program:socat]
command=socat -d -d pty,raw,echo=0,link=/home/pi/smarty_proxy_pts TCP-LISTEN:2001,reuseaddr
priority=10
autostart=true
autorestart=true
user=pi

[program:smarty_dsmr_proxy]
command=python3 /home/pi/smarty_dsmr_proxy/decrypt.py DECRYPTION_KEY --serial-output-port=/home/pi/smarty_proxy_pts
priority=20
autostart=true
autorestart=true
user=pi

And then start it (or simply restart your device):

sudo service supervisor restart

Further information

• DSMR Component for Home Assistant
• DSMR Parser, the library used by Home Assistant to read meter data
• DSMR Reader, stand-alone utility to log and view your energy consumption
• P1 Port Specification for Luxembourg's "Smarty" electricity meter, the reference document for this library. It describes how the encryption on top of the DSMR standard works.