I have a unused RPi4 (the 8Gig one) running DietPi.
I did use it as a playground but ever since I am renting a Hetzner machine for (playground) stuff that I want web accessible, I don't have particular use for the Pi.
I am currently running (outdated) Home Assistant on it but there isn't much I can connect it with (yet, getting the flashable/compatible ikea smart lightning zigbee? bridge thingy is on my bucket list).
Obviously I do have a pihole there.
Shoot me any other ideas I could run there.
Some kind of monitoring of my rented infra would be cool (I already have uptime kuma on the dedi hetzner box). One idea I had was if there are some OSS security scanning "daemons" I could use on to monitor my other infra.
About a minute, 1:30 maybe (edit: per page on a pi4). I use an app to upload jpegs though, I don't have a normal scanner at the moment. The higher quality scan and smaller file size may make some steps of the process quicker (no need for alignment and color correction for example) if you use a normal, proper scanner.
It doesn't matter though. When I get home and see I got a letter I scan it and by the time I drank something, put away my clothes and stuff i had with me, the pi is done and I can edit the metadata in the web ui.
I have a pi4, 4GB. And running off of an SSD (connected via SATA to usb adapter). Sorry, forgot to specify.
Even slower would still be worth it IMO, digital document management is just so much better than keeping multiple folders of paper organized. Also I can access all my paperwork from anywhere, because the pi and my phone are both in my wireguard VPN network.