Patent ID: 7224284
Filing Date: 2007-05-29
Classification: G08B

Abstract:
1. A method of calibrating a smoke detector having a variable output LED light source, a smoke evaluation chamber, a light receiver and a circuit for measuring the output of the light receiver, said method comprising: providing said smoke evaluation chamber with a first known obscuration atmosphere and determining a first measured output value of the light receiver; providing said smoke evaluation chamber with a second known obscuration atmosphere and determining a second measured output value of the light receiver; adjusting the output of the LED light source based on the first and second measured output values to achieve a predetermined sensitivity of the detector calculated by the ratio of change in measured output versus change in obscuration; determining an offset value used in combination with said predetermined sensitivity to predict the response of the detector for different levels of obscuration; using said offset value and said predetermined sensitivity to set at lease one alarm value; and storing said offset value in said smoke detector.