To solve this problem, [Pavol Sedlacek] has created a supercapacitor-based UPS specifically for the ... it works in reverse to take power from the capacitors and feed it back to the Pi.
Do you power the Pi separately, or make a UPS for it? [Lutz Lisseck] decided he wanted to turn his ambient-lamp (Rundbuntplasma) on and off with only the main power switch in his Hackerpsace.