My Stevenson screen has a 12V supply to it for powering the 1-wire hub that has all my weather sensors attached to it. At the moment the main 1-wire connection runs back to the PC in the observatory warm room, but I decided it would be a little neater if I had a Raspberry Pi in the screen itself and used that to collect the 1-wire data. The question was, how to power the Pi?
After turning the idea over in my head for a while it occurred to me that if I had a 12V USB charging device I could just plug the Pi straight into that. And then a little more searching revealed the existence of sockets presumably intended to fit in the same sort of holes as car lighter sockets that provide USB charging points and take a 12V supply. From there it was easy.
I bought such a socket and a splitter cable for my 12V supply. One side of the splitter went to the 1-wire hub. The socket I bought came with spade connectors, so I connected them to the other side of the splitter. A quick bit of 3D printing gave me a bracket for mounting the socket and then it was just a case of plugging the Pi into the socket output.
The Pi seems quite happy to run in this way, though I did need to replace the original USB cable with a better one so the Pi didn’t get reset when the cable moved.
