The project detects flammable gases (LPG, butane, propane, methane, alcohol, hydrogen, etc.) via the MQ2 Gas Sensor. When a flammable gas is detected the frequency of the speaker beep increases.
The whole enchilada is controlled by a PICAXE 08M uController and some custom code. Thanks to all on the forum that have helped to educate me through your posts.
Full documentation at: http://ijprojects.blogspot.com/2011/11/picaxe-mq2-gas-sensor-project-in-mouse.html