One Man’s Trash Is Another Man’s Compute Cluster
hackster.io
hackster.io
https://dl.acm.org/doi/pdf/10.1145/3575693.3575710
It’s quite a nice, albeit not novel, idea, that definitely beats most if not all SFFs for small applications. Raspberries also can’t meaningfully compete with a standard smartphone wrt either performance or availability.
What I'd really love is to have a straight Ubuntu Server install for old android phones with nothing but a tty on the phone's screen.
Discussed on HN a couple of times: https://hn.algolia.com/?q=postmarketOS
I highly recommend checking them out.
You can buy lots of obsolete stuff new from surplus inventory from scavengers.
Regarding the OP, battery is a problem. These old phones have bad batteries, and buying a new battery undercuts the carbon savings. And there's no need to use a phone battery as your server battery -- you can use any external battery.