After many errors and a bit of code restructuring, the temperatures and pressure are finally displayed correctly. The OLED now updates once per minute with the latest readings. Every 15 minutes, the device sends an averaged value (covering the last 15 minutes) via MQTT to my Raspberry Pi broker.

As mentioned in a previous post, the broker and topics are customizable in the web interface.

So far, everything works exactly as expected—and I’m really happy with the results! :)