Ultraloud smoke detector
First Claim
1. An ambient condition detector comprising:
- a housing;
an ambient condition sensor carried by the housing;
a control circuit, coupled to the sensor, for determining if a selected condition has been indicated by the sensor and for establishing an alarm indicating signal in response thereto wherein the control circuit includes a feedback circuit for increasing the sensitivity of the detector for a predetermined period of time in response to the control circuit having established the alarm indicating signal.
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Accused Products
Abstract
An ultraloud ambient condition detector incorporates a sensor in combination with a control circuit. An alarm indicating signal from the control circuit energizes a multi-frequency drive circuit which produces a band of output frequencies usable to drive a piezoelectric output element. The output element has one or more resonant frequencies which fall within the band of the drive frequencies. A feedback circuit is provided to maintain the unit in an alarm state, after it has switched into that state, even if the input ambient condition indicator signals a decline in the value of the sensed ambient condition or in the presence of noise perhaps generated by the audio output device. A high current, low duty cycle battery test current repetitively loads the battery consistent with current load when the detector is in an alarm state.
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Citations
19 Claims
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1. An ambient condition detector comprising:
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a housing; an ambient condition sensor carried by the housing; a control circuit, coupled to the sensor, for determining if a selected condition has been indicated by the sensor and for establishing an alarm indicating signal in response thereto wherein the control circuit includes a feedback circuit for increasing the sensitivity of the detector for a predetermined period of time in response to the control circuit having established the alarm indicating signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An ultraloud smoke detector comprising:
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a smoke sensor; a control circuit having a preselected sensitivity, coupled to the smoke sensor, for actuating an alarm by generating a signal indicative of a predetermined level of smoke; a multi-frequency signal generator coupled to the control circuit for repetitively generating a band of frequencies when activated in response to the predetermined level of smoke; an audible output device, coupled to the generator, having at least one resonant frequency in the band of frequencies; and a feedback circuit, coupled across the control circuit and responsive to the smoke indicative signal for temporarily increasing the sensitivity in response to the presence of the smoke indicative signal. - View Dependent Claims (17)
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18. A variable sensitivity ambient condition detector comprising:
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a sensor; a comparator having two inputs and an output wherein one input is coupled to the sensor and wherein the output goes from a first state to a second state, actuating an alarm, in response to the inputs assuming a predetermined relationship indicative of a first sensitivity level; a threshold establishing circuit with a threshold node coupled to the other input and wherein the circuit establishes a quiescent threshold value at the node; and an R-C type threshold altering circuit coupled between the output of the comparator and the threshold node wherein in response to the sensor generating a signal indicating the presence of a selected condition and the output of the comparator going from the first state to the second state, in response thereto, the quiescent value is altered to temporarily increase the sensitivity from the first level to a second, more sensitive, level thereby temporarily holding the comparator in the second state even in the presence of transient variations in the signal generated by the sensor. - View Dependent Claims (19)
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Specification