http://www.acroname.com/robotics/parts/R67-UVTRON.html

This detector is amazing. Using the included sample circuit, you can detect a match lighting from 5 meters in a sunny room! Since the UV energy emitted by a flame bounces off walls, you don't even need to have a line of sight to the flame to detect it in a room.

Included with each package is a booklet including specifications, application hints, and sample code for using the circuit and detector to detect candles and other sources of UV radiation.