I have a pi 3 B+ running as an LTE to WiFi gateway. I'm not using the native WiFi but the ethernet is connected to an openwrt router.
Since I had ram to spare it also does:
- dhcp
- caching DNS + filtering
- Mqtt server
- GPS-based NTP server
- Openvpn server to my nas (at a different location) and vps
My main one is for ADSB using adsb-lol.
I also have the Pimoroni Enviro+ in my living room. I've got their Grow kit somewhere as well, but... no plants since I moved.
I used to have a Kubernetes cluster running on some Pi3's, but they got a little too slow and I was bumping up against the lower memory. Lots of other self-hosted stuff, but it's all on some old off-lease computers I found cheap, not on a Pi.
In active use:
retropie - pi3b+
gps based ntp (2x pi2 + gps hats. Chrony rocks.)
rtl_433 monitor for 915 and another for 433 (2x pi2, 2x rtl-sdr sticks)
an ads-b 1090 monitor (pi3 + rtl-sdr stick)
libreelec - plex clients (2x pi4 (1GB and 2GB)
an emulated macintosh (pi3)
a flood monitor in the basement (pi1)
an aarch64 dev platform (cm4-8GB) and another (pi5-8GB)
We're running three right now:
One runs our boat's primary navigation system with Signal K and connects to the instruments via an NMEA2000 hat.
The second one is the boat NAS.
The third one powers an info display on the nav table.
My longest running Raspberry Pis are using HifiBerry HATs. Acting as SnapCast clients, forming a poor man's Sonos system throughout the house. The oldest running Pi is a 2.
PiHole
I have one running home assistant, I have one running a duet web server for a printer, and I have one that runs cncjs for a mill.
the home assistant one runs a reverse proxy and adguard/tailscale docker among other things.
they're useful but the price point sucks right now unless you absolutely need the IO ports/shields they provide. I have a PoE shield on my home assistant one that makes the installation very tidy.