TPA81, 8 pixel array of thermal sensors that can detect a candle flame at a distance of 2 meters ( not disturbed by ambient light) . And can detect human body heat.
Dimension: 31mm ( D) x 18mm ( L) .
more info:
http: / / 2r-he.blogspot.com/ 2009/ 10/ tpa81-8-pixel-array-of-thermal-senso rs.html