This tidy little 1 row x 8 element thermopile sensor reads the temperature across a 41 degree sweep. And it can control a servo to automatically pan and create it's own thermal image!
The Devantech TPA81 Thermopile array is a single row of 8 thermal elements, which gives you the nifty ability to scan in a single dimension looking for the heat signatures, and tell what temperature at each zone is. It uses an I2C interface, much like the rest of the Devantech sensor line.
It can detect a candle flame at a range of 2 meters (6'6")!
And here's something real cool: It can control it's own panning servo to build up a thermal image!