Mad Dash for Flash Cash 2002 – Third Prize
Spehro Pefhany, Canada
The Chimney Sentinel is aimed at preventing fires caused by wood-burning appliances. The device consists of a probe inserted in the chimney and a remote microcontroller-based monitoring unit. When a fire is detected, the Chimney Sentinel sounds an alarm (before smoke has time to reach other detectors within the home). Additionally, it helps prevent fires by monitoring the conditions in the chimney. Creosote tends to build up in chimneys when the temperature in the flue is too low; this build-up can lead to a fire. The Sentinel detects when the flue temperature is in the danger range, and then sounds an alarm if the temperature does not move through the danger zone quickly enough. Even if the heat is such that the sensor is destroyed (the melting point is in excess of 2500°F), the monitor will continue sounding an alarm. The heart of the circuit is an 8-bit PIC16F628 microcontroller with flash memory.