sunsniff 0.1.0

Intercept and store telemetry from a Sunsynk inverter
Documentation

Inverter telemetry capture

This program is designed to run on a router sitting between an inverter with an Inteless WiFi dongle and the remote server, intercept the sensor data, and make it available for use.

This is pre-alpha software. All the schemas may change. The data you collect might vanish, or leak onto the internet (but it's already being sent unencrypted, which is why this project works in the first place). The config file format may change. It may hang your router. While it supports authentication, none of the interfaces have been tested with TLS.

The good news is that by design it intercepts traffic but does not send any commands to your inverter, so it can't interfere with the inverter's operation.

Compilation

  1. Install Rust e.g. using these instructions.
  2. Ensure that you have a C compiler and linker, and libpcap installed.
  3. Run cargo build --release. This will compile the binary to target/release/sunsniff.

If you want to cross-compile:

  1. Install and set up cross e.g. using these instructions.
  2. Run cross build --release --target=armv7-unknown-linux-gnueabihf (replace with your target architecture).
  3. Find the binary in target/<arch>/release/target.

I had problems because the resulting binary needed a newer glibc than the host I was targeting. To build a static binary, set the environment variable RUSTFLAGS to -C target-feature=+crt-static -lpcap.

Configuration

Configuration is stored in a TOML file, which is passed on the command line. There is one mandatory section, [pcap]. It has the following fields:

  • device (required): the Ethernet device to capture. Note that the any device is not currently supported.
  • filter (optional but recommended): A pcap filter to select the traffic to inspect. If the device handles data for any other devices on the network then setting filter is necessary to prevent other data from being accidentally interpreted as sensor readings.
  • file (optional): if set to true, then device is interpreted as a pcap file rather than a device. Note that the pcap file is fully loaded into memory, so it should not be used with very large files.
  • timezone (required): The timezone name used by the inverter. This is used to convert the timestamps to UTC.

I have the following setup:

[pcap]
device = "br0"
filter = "src host 192.168.0.21"
timezone = "Africa/Johannesburg"

This just configures the data capture, but you should also specify at least one backend to actually do something with it. For each backend type you can configure multiple instances. This is why the section names are in double brackets.

Influxdb2 backend

The readings are inserted into an Influxdb bucket. Note that the schema is not final.

The configuration section looks like this:

[[influxdb2]]
host = "http://192.168.0.123:8086/"
org = "my_org"
bucket = "my_bucket"
token = "..."

The implementation tries very hard to deal with intermittent connections to Influxdb, buffering messages until it is able to deliver them (but only in memory; if the service is stopped, any pending messages are lost). Since the updates are only sent every 5 minutes is can be quite practical to buffer messages for hours or days, and I'm currently running the Influxdb server on my home PC which is switched off at night.

The downside of this robustness is that if you get the configuration wrong, the server won't stop with an error. It will just keep trying to deliver, and use more and more memory to buffer the incoming messages.

MQTT backend (Home Assistant)

This backend publishes sensor values to an MQTT broker. The topics are specifically designed for use with Home Assistant and provide the appropriate discovery information, but this doesn't prevent other use cases. You will need to install an MQTT broker (Home Assistant supports Mosquitto as an add-on) and configure Home Assistant to use it. A typical configuration then looks like this:

[[mqtt]]
url = "mqtt://192.168.0.123:1883"
username = "my_username"
password = "my_password"

The username and password can be omitted if the broker doesn't require authentication.

Unfortunately the MQTT library I'm using doesn't support MQTT last will messages, so there is no availability information to indicate that the service is running.

Supported hardware

So far I've only tested this with my personal setup. I'm hoping other devices will work too. If it works for you, please let me know.

  • Inverter: Sunsynk 5 kW (Sunsynk-5K-SG01LP1)
  • Dongle: unbranded Inteless dongle (it has red and green lights). Apparently the Sunsynk-branded dongle is the same thing.

Troubleshooting

Logging is done with env_logger, so you can enable debugging by setting the environment variable RUST_LOG=debug. There isn't very much logging yet though.

TODO:

  • Explain what to look for in a packet capture
  • Explain that missing pcap filter can cause bogus data