Aside from digital thermometers, what are some other clever uses of the Arduino platform as applied to homebrewing? Anything such as novel gadgetry, process automation and/or DIY equipment is especially interesting to me?
I believe the Brewtroller project http://www.brewtroller.com/wiki/doku.php is based on the arduino platform. It has grown into custom boards, interfaces and such but I think it still has a stock arduino package that you can use as well.
I have seen a light gate used to sense bubbling in an airlock to measure fermentation rates. Very slick implementation and obviously useful data.
Paired with a temp-controlled environment, one could control the rate of fermentation by adjusting the temperature, instead of just relying on a set temperature.
I never did it, but I was poking around with using one to adjust the flow-rate of my strike water, so I could maintain a particular temperature while mashing in.
I have heard that Corsair uses one in their distillery, but I don't know if that's for the distillation process, the brewing process, or both.
There's another pretty nice board out there LPC1769 LPCXpresso board (LPCTools.com).
It's an ARM Cortex-3 processor with a complete development environment, all the software is free, including and Eclipse-based IDE (that's integrated development environment for the non-coders out there). The board itself costs 30 bucks, and all you need is a USB cable to plug it into a Windows, a Mac, or a Linux machine. It actually has two processors. The LPC 1768 is the interface for USB. And then the LPC 1769 is the actual target processor on this little board. And you'd be coding on a processor that is used in smart phones, so maybe could be useful skills, and not just for brewing, hehe.