초록 ▼

A CO concentration monitoring device operating under the control of a processor periodically checks the CO sensor to insure its ongoing integrity and to issue a distinctive audio signal to a user if sensor integrity has become suspect. The periodic integrity check procedure places a predetermined DC

A CO concentration monitoring device operating under the control of a processor periodically checks the CO sensor to insure its ongoing integrity and to issue a distinctive audio signal to a user if sensor integrity has become suspect. The periodic integrity check procedure places a predetermined DC voltage across the sensor. Then, the voltage source is removed leaving the sensor charged as a capacitor such that reading the voltage remaining across the sensor, reading the temperature of the sensor and comparing a temperature adjusted representation of the voltage appearing across the sensor to at least one predetermined representation of a voltage representing a threshold at which sensor integrity becomes suspect. If this condition is determined, a sensor condition alert signal responsive is issued to drive a horn in a distinctive audio sequence (e.g., three 10 millisecond duration pulses spaced at about 500 millisecond intervals). In an optional feature, a manually actuable switch serves to selectively inhibit drive to the horn for a predetermined period if the sensor integrity condition has been determined to be marginal, but not yet failing.

대표청구항 ▼

[ What is claimed is:] [1.] A dangerous condition warning device adapted to issue an alarm when the ambient carbon monoxide level exceeds a predetermined level, said dangerous condition monitoring device comprising a dangerous condition monitoring device circuit including:A) a processor;B) a carbon

[ What is claimed is:] [1.] A dangerous condition warning device adapted to issue an alarm when the ambient carbon monoxide level exceeds a predetermined level, said dangerous condition monitoring device comprising a dangerous condition monitoring device circuit including:A) a processor;B) a carbon monoxide level sensor characterized in that it has first and second terminals and can be charged as a capacitor by applying a DC voltage across said first and second terminals;C) carbon monoxide concentration determination means for periodically polling said carbon monoxide sensor by said processor to monitor the ambient concentration of carbon monoxide;D) an audio annunciator;E) sensor integrity checking means for periodically assessing said carbon monoxide sensor under control of said processor by:1) placing a predetermined DC voltage in series with a resistor across said first and second terminals to charge it as a capacitor;2) removing the predetermined DC voltage from said first and second terminals leaving the carbon monoxide sensor charged as a capacitor;3) reading the voltage appearing across the carbon monoxide sensor;4) reading the temperature of the carbon monoxide sensor; and5) comparing a temperature adjusted representation of the voltage appearing across the carbon monoxide sensor to first and second predetermined representations of voltages representing first and second thresholds for determining, by comparison to said representation of the voltage appearing across the carbon monoxide sensor:a) a first sensor integrity condition in which sensor failure can be expected after a relatively long period; andb) a second sensor integrity condition in which sensor failure is imminent and action should be taken;F) sensor condition alert signal means responsive to the determination of said first and second sensor integrity conditions for driving said audio annunciator in a distinctive audio sequence of three 10 millisecond duration pulses spaced at about 500 millisecond intervals, which audio sequence is repeated at about five minute intervals;G) a manually actuable switch;H) means responsive to actuation of said manually-actuable switch for inhibiting drive to said audio annunciator for a predetermined period if said first sensor integrity condition is detected; andI) means responsive to actuation of said manually-actuable switch after said second sensor integrity condition has been detected for preventing inhibiting the drive to said audio annunciator.