My Little Ruuvi Setup

I.e. how I record and display the measurements collected from the excellent Ruuvi sensors.

The main design driver for this project is that I want something dirt simple and easy to maintain. Currently it requires one to just copy a bunch of files and create an autostart script so that both everything works on a Raspberry Pi.

TBD and other musings:

• Currently everything runs on a Raspberry Pi 3B rev 1.3, but the plan is to set up an SCP to copy over the files to a proper server so I could access the data outside my home network.
• In addition to that, there needs to be some kind of day or week or month based versioning of the data at that point so that the SCP job stays fast.
• There's currently no old data cleanup. While there's plenty of space on the SD the Pi runs from, it's not exactly a safe place to store data in the long term.

Components

Measurement collection

ruuvitag-jsonl-socket-bridge is used for collecting measurements from the sensors.

Data management

measurement_collector.py stores the observations into an SQLite3

SQLite was chosen as the storage backend as it's dead simple to operate, and performant enough even on a Raspberry Pi. I used to have a setup running on a Pi based on InfluxDB, but at some point it just broke down due to the amount of data, refused to start up due to running out of memory, and I ended up losing the data. It might be possible to make InfluxDB run on a Raspberry Pi, but I have no interest in learning how to do that as I think it's generally an overkill for the use case. With SQLite I can keep it simple.

Data visualization

Measurements are visualized using a single page application (SPA) served by measurement_browser.py. The script contains both the HTTP server to serve the SPA and the interface the SPA uses to request the actual measurement data.

Measurement times are quantized to the minute (or when summaries are used, to the summary's period) during query time to have matching timestamps between different sensors for the visualization library. Measurements have an accurate timestamp in the database.

Installation incantations

loginctl enable-linger
mkdir -p ~/.config/systemd/user/
# scp .service files into that dir
systemctl --user enable measurement_collector.service
systemctl --user enable measurement_browser.service
systemctl --user start measurement_collector
systemctl --user start measurement_browser
systemctl --user status

# If you make changes to service files to e.g. enable debug logging, the
# following will take care of that:
systemctl --user daemon-reload
systemctl --user restart measurement_collector
systemctl --user restart measurement_browser

# To access the logs of the services:
journalctl --user -u measurement_collector
journalctl --user -u measurement_browser

Licensing

This piece of software is licensed under GPLv3.