David Hayward over at CNET UK has posted an article describing how he designed a solar powered FTP server based on the R-Pi. The additional hardware consists of a solar cell array and 4 NiMH batteries. The solar panel is by Cottonpickers, but you could use any appropriately rated panel. (Be sure to include appropriate voltage regulation, as the R-Pi is very voltage sensitive.) The article provides step by step instructions on how to install and configure the necessary software to turn the Pi into an FTP server.
Such a solar powered setup could be useful for downloading sensor data from a remote monitoring station, though solar conditions and the project’s current draw could limit the amount of functional time.
Via CNET UK.