InfluxDB (https://www.influxdata.com/) is a time-series database perfectly suited for the storage of sensor values, and because it provides a Python client library I was able to write an IOData agent app. I'm very keen on InfluxDB because it is natively supported by Grafana (https://grafana.com/), a beautiful, flexible data visualisation suite. After installing InfluxDB and Grafana and launching the swb_influxdb_save app all the Switchboard device values are automatically stored. When creating the following dashboard I was able to select the devices I wanted to plot from a drop-down menu:

At around 13:53:40 I blew on the DHT22 sensor causing the spikes in humidity and temperature. Grafana comes with a bit of a learning curve, but it is so powerful and flexible that you won't regret looking into it.

As usual, a rough guide on how to setup this app can be found in the repo in the apps/swb_influxdb_save/README.md file.