Patent ID: 7690583
Filing Date: 2010-04-06
Classification: F24F,G05D

Abstract:
1. A device for controlling an exhaust fan, comprising: a sensor that periodically senses a humidity level in a room and provides a corresponding sensed periodic humidity signal having a corresponding periodic value indicative of the associated periodic sensed humidity levels; a processor that calculates an average humidity value over a period of time from the periodic sensed humidity signal values over the period of time and provides a current calculated average humidity value, where the processor compares a current periodic sensed humidity signal value to a first threshold humidity value that is a function of the current calculated average humidity value and if the current periodic sensed humidity signal value has a predetermined relationship to the first threshold humidity value the processor provides a signal to turn on the exhaust fan for a period of time, where if the exhaust fan is turned on as a result of the current periodic sensed humidity signal value having the predetermined relationship to the first threshold humidity value the processor compares the current periodic sensed humidity signal value to a second threshold humidity value that is a function of the current calculated average humidity value and if the current periodic sensed humidity signal value has a predetermined relationship to the second threshold humidity value the processor provides a signal to turn off the exhaust fan.