I've got three Raspberry Pies running now, doing useful work.
The first is running the Geocaching Robot Arm. The second one is watching my front garden; that replaces a full-size server that ran with an annoying high-pitched whistle, which mattered less because it was a long way away from where we usually are. But by replacing it, I reduce the noise and the power consumption.
While I was getting that up and running, I accidentally discovered gphoto. That lets you control a camera via the USB port. I have a Canon Powershot A620 that I used before mobile phone cameras got so good, and it's just been sitting around doing nothing. So I connected it up, and fumbled around for ages before I finally worked out that to put it in "PTP mode" (Picture Transfer Protocol) you press the button with the printer icon (I'd been guessing that it would be somewhere on the menus, and the manual is upstairs with my collection of manuals). Then it was easy - I can tell it to take a picture and download it to the computer, and the pictures are absolutely beautiful, massively better than the webcams I'm using for the Robot Arm. Which isn't a surprise. So all I need to do now, is dream up some use for this.
I'll think of something.
The third one, just installed, is very minimalist.
It's getting power from the USB port of another server, over a cable that came with my Nokia mobile phone, now no longer in use since I inherited ladysolly's iPhone. The SD card is just 2 gb, wihch is less than the recommended 4gb because A) I wanted to see if I could, and B) there's still 1/2 gb of spare space, and C) I had a couple of 2gb cards lying around doing nothing, and D) all the files it uses are stored on another server, which is a big brute with lots of disk space and E) all the stuff that I ordered to support the pies (USB hubs, cables, power supplies, SD cards) is somewhere between here and China, because I didn't think I'd be wanting them until the end of December. But RS components delivered early, which is nice.
I phoned them up about the missing Pi; I thouht I'd have quite a struggle with them, because how can I prove that it wasn't there? But they were nice as pie about it (couldn't resist that) and they'll be sending one along as soon as they have stock. So I'm happy about that.
I also discovered that the packaging that RS put round the pies, works well as a case; I used a hacksaw to make a small hole for the power lead and another hole for the ethernet cable, an elastic band to secure it colsed and a label on the outside to say which computer it is, and that's it; I don't need to use the USB ports, the video or the audio, for most of what I have in mind.
I plan to go out caching tomorrow; I haven't decided where yet, but the weather looks to be good.