Abstract: A low profile, low volume smoke chamber displaces a light source, such as a light emitting diode or laser diode, and a sensor, such as photodiode or phototransistor, to the exterior of the sensing volume. A symmetrical sensing volume results which can be coupled to symmetrical input/output ports via a generally U-shaped flow path. A two part sensing chamber housing is formed with a lower cylindrical base portion and an upper cylindrical cover portion which slideably engage one another. At least the upper cylindrical portion carries a plurality of grooves for suppression of reflections and collection of dust. An exterior end of the upper portion carries a plurality of spaced apart openings which can be filled with a screen. A reduced sensing volume in combination with a selected screen size produces an acceptable signal to noise ratio and response rate while still excluding insects and other non-smoke related particulate matter.

Abstract: A modular door access control system incorporates a plurality of wireless door modules. Access request signals are transmitted to a remote access control unit. The control unit transmits access authorizing control signals to a respective one of the modules. A newly installed module, in a selected mode, enters into communication with the unit. The unit in turn transmits an identifier to the module for use in identifying itself to the unit subsequently in response to a received access request.

Abstract: A rechargeable battery-operated flashlight system includes a housing for the flashlight, batteries and associated circuitry. A two-pronged plug is rotatably mounted in the housing for movement between two positions, the prongs projecting outwardly through an opening in the housing so that in one position they project into a recess formed by a reentrant portion of the housing and in the other position they project away from the recess. Resilient contacts connect the prongs to the rest of the circuitry, and engage in detents on the prongs in their two positions to inhibit rotation thereof. A wall bracket defines a pocket for releasably accommodating a receptacle fixture for receiving the plug prongs in their one position and for supporting the housing during recharging. In their other position, the prongs can be plugged directly into an AC wall outlet.

Abstract: A flashlight has a built-in passive battery charging circuit adapted to be plugged into an associated AC source, and a selector switch for selectively connecting the battery to the charging circuit or to the flashlight lamp. The charging circuit includes a transformer with a center-tapped secondary providing a high voltage at one set of terminals and a low voltage at another set of terminals. The high voltage is rectified by an LED and applied through a current-limiting resistor to the selector switch. The low voltage is full-wave rectified by a diode bridge, the output terminals of which are coupled to the selector switch. Also connected across the output terminals of the diode bridge is a Zener diode circuit for terminating current flow from the bridge to the battery when the battery voltage reaches a predetermined level.

Abstract: A storage battery comprises interleaved anode and cathode electrodes and an electrolyte between them. A pair of oppositely poled diodes is coupled in parallel between one of the electrodes and one of the terminals of the battery, the other electrode being coupled to the other battery terminal.

Abstract: A flashlight has a battery housing and a head. A carriage is slidably mounted on opposing walls of the head. The carriage carries a socket for holding a flashlight bulb. A tab on the carriage is accessible to one's finger to enable movement of the carriage and the bulb carried thereby in any one of a number of positions, thereby to control the beam width.

Abstract: A battery powered products of combustion detector and warning device, which is interconnectable in a detecting system with other similar devices, is characterized by means for providing separate, distinct and sensibly perceptible signals representative of (a) a standby or quiescent condition of the device, (b) the energy level of the battery decreasing to at least a predetermined level, (c) the sensitivity of the device to the phenomena decreasing to at least a selected level, (d) detection by the device of the occurrence of the phenomena, or (e) detection of the phenomena by another warning device interconnected therewith. In consequence, a user of the warning device is readily and continuously apprised of the operating condition and state of the device.

Abstract: This electrode assembly includes two relatively large-diameter, parallel conductive discs spaced apart by an annular insulator which has peripheral flanges respectively encompassing the perimeters of the discs. The assembly is adapted to be disposed in an ionization chamber formed by a printed circuit board and a conductive cup mounted thereon. One of the discs has conductive mounting legs adapted to be snap-fitted into complementary openings in the circuit board for spacing the disc from the board a distance sufficient to permit the mounting of associated electronic components therebetween. Both discs have pronged attachment apertures adapted for one-way press-fitting engagement with corresponding attachment posts on the insulating body, one disc having a central aperture for mounting an associated radioactive source thereon. The other disc cooperates with the one disc to define a reference zone therebetween and cooperates with the metal cup to define a sampling zone of the ionization chamber.

Abstract: An improved fire detector has both ionization chamber and photoelectric type products of combustion sensing devices, both of which must detect combustion for an alarm to be generated. The sensing devices are each adjusted to a quiescent sensitivity, but upon combustion being detected by one of the devices the sensitivity of the other device is automatically increased. In this manner, the detector operates very reliably to generate an alarm in the very early stages of a fire irrespective of whether the combustion process generates primarily visible or generally invisible type products of combustion, yet spurious generation of false alarm is minimized.

Abstract: Apparatus for supervising the energy level of a battery is characterized by circuitry for periodically loading the battery, monitoring the change in voltage across the battery from the condition prior to loading to during loading, and generating a signal whenever the change in voltage is at least equal to a predetermined magnitude. In one embodiment the apparatus is used with a fire detector powered by the battery, and the signal operates an alarm to indicate impending battery failure.

Abstract: An improved warning device having a sensor responsive to predetermined phenomena to generate a signal which changes in value upon the presence of the phenomena, and means for comparing the signal with a reference potential and for generating an indication upon a predetermined difference therebetween, is characterized by integrated circuit components which may economically be manufactured and assembled, and which maintain substantially constant the sensitivity of the device to the phenomena despite changes in the level of power supplied thereto. Where the warning device is a battery powered fire detector, the phenomena to be sensed is products of combustion, circuitry supervises the power level of the battery, and means are provided for readily testing the entire combustion detecting and indication generating portion of the detector, whereby a user of the detector may be assured of proper operation of the detector in response to combustion.

Abstract: A detecting device having a sensor responsive to the presence of predetermined phenomena to generate a signal which changes from a nominal value by an amount in accordance with concentrations of the phenomena, and circuitry connected with the sensor to monitor the signal and adjustable to generate an indication upon the signal changing by at least a selected first amount, is characterized by means for operating the sensor to selectively change the signal in the absence of the phenomena by either the first amount or by a second predetermined and greater amount. Where the detector is a fire detector, the phenomena to be sensed is products of combustion, and the signal changes by the first amount upon the presence of products of combustion in the minimum concentrationswhereat it is desired to generate an indication, and by the second amount upon the presence of products of combustion in the maximum concentrations which may occur before generation of an indication is necessary.

Abstract: An improved early warning fire detector of the ionization type is provided wherein detection circuitry having adjustable sensitivity is connected to an ionization chamber responsive to products of combustion. A supervisory circuit monitors the unit to assure that power is applied to the unit, that the detecting circuitry is operative and that the unit is operating at the proper sensitivity.