Abstract: A smoke detector having an audible missing primary power source indicator, capable of indicating the absence of a primary power source powering the detector is provided. A missing power source circuit, including a supplementary power source having an effective voltage below a predetermined reference value is connected in parallel with the primary power source of the smoke detector. Additionally, the smoke detector contains low voltage detection and alarm circuitry, connected to the primary and supplementary power sources, to produce an audible warning when the effective voltage powering the smoke detector is determined to be below a predetermined reference value. Primary power to the detector may be supplied by a DC battery, a DC power source which has been converted from AC power or by a combination of the two.

Abstract: A smoke alarm device including self-test reminder circuitry is provided. The smoke alarm includes smoke detection circuitry and a smoke sensor, the functionality of which may be tested using a test switch connected in parallel across the smoke sensor. Additionally, a reminder circuit is provided, the output of which may be used to enable an indicator. The indicator may be the horn or annunciator of the smoke detector, or may be some other type of indicator, such as a light or other audible indicator. Periodically, the reminder circuit will cause the indicator to become enabled so as to remind the consumer to test the smoke alarm. The indicator will remain enabled until the reminder circuit is manually reset by the consumer. Actuation of the test switch simultaneously tests the functionality of the smoke detection circuitry and resets the reminder circuit.

Abstract: A deflectable battery retaining member in a battery powered unit blocks the improper insertion of a battery into the unit. Further, the same member in the absence of a battery inhibits engagement of the cover of the unit thereto providing a visual indicator of the missing battery.

Abstract: A smoke detector with a visual battery missing indicator and a removable cover includes first and second locking prongs molded in the detector and directed toward the cover. A battery is positionable between the first and second locking prongs deflecting same from a non-locking position to a locking position. In the locking position, free ends of the prongs can engage the cover, locking same to the detector. In the non-locking position, the prongs are not effective to engage the cover. If the detector is mounted on a ceiling, the non-engaged cover will not remain closed. In an alternate embodiment usable with a bracket mounted detector, a depressible blocking member is located adjacent a region where the detector is normally coupled to a portion of the bracket. In the presence of a battery this member is retracted, enabling the unit to be attached to the bracket. In the absence of a battery, this member is extended and the detector cannot be attached to the bracket.

Abstract: A system for testing a remotely located sensing unit includes a photosensor located within the sensing unit. A control beam of incident electromagnetic energy can be provided from a remotely located portable source such as a flashlight. Directing the beam of radiant energy from the flashlight against the sensor in the unit causes the unit to initiate a test sequence. The unit can be equipped with a photo-detector to terminate an alarm generated in response to a sensed condition. The unit can include a sonic detector. Control circuitry in the unit can decode a sensed encoded incident beam to minimize false tests or to provide multiple remotely initiated functions.

Abstract: A system for testing a remotely located sensing unit includes a photosensor located within the sensing unit. A control beam of incident electromagnetic energy can be provided from a remotely located portable source such as a flashlight. Directing the beam of radiant energy from the flashlight against the sensor in the unit causes the unit to initiate a test sequence. The unit can be equipped with a photo-detector to terminate an alarm generated in response to a sensed condition. The unit can include a sonic detector. Control circuitry in the unit can decode a sensed encoded incident beam to minimize false tests or to provide multiple remotely initiated functions.