Possible Raspberry Pi project

For a while now I've been wondering idly how I could measure cloudiness. My goal is to both track how cloudy it is now (and over time), and to compare actual cloudiness with predictions from ClearSkyChart.

A few days ago I came across an approach that I think might work. This person measured the current coming from a Peltier cooler when exposed to the night sky. The difference in temperature between the ground-facing side (warm) and the sky-facing side (cold) varied depending on whether it was cloudy (less difference in temp == less current) or not (greater difference in temp == more current). It occurred to me that I could use a Raspberry Pi I've got lying around to take that same approach.

Since then I've been browsing around, and here's what I've found:

• A big-ass Peltier cooler on Amazon
• A thread on the Raspberry Pi forums on digital multimeters with USB output (who knew?)
• A crapton of USB multimeters (so, wait, you mean I don't have to solder my own voltage meter?)
• The Sigrok project, which is a generic signal analysis project for Linux et al.
• Another page on Linux software for reading from serial adapter-equipped multimeters
• The PyDMM project, which looks old but hey, Python!

I'm starting to think I've got a good approach here.