This is the machine hosting my Mastodon instance, MQTT service, Slack bot, remote backup, and custom made home-automation service.
Over the years I consolidated a lot of machines and VPSs into this Raspberry Pi.
@beto I've really been super tempted to do this too. I have a pi doing not much more than occasionally running a mastodon bot.
I use https://hoppy.network/ so that the Raspi can have a real IP address, for a total cost of $8/month.
The external HD is used for remote backups for my laptop (my main computer) using Duplicity. This replaced and old HP microserver that I used as a NAS.
For home automation I've developed Señor Octopus (https://github.com/betodealmeida/senor-octopus). I use it to control my lights, collect data from sensors, monitor air quality and much more.
I use Apache Superset (https://github.com/apache/superset/) to visualize the data.