Abstract: A smoke detector is provided with testing apparatus for determining if its sensitivity is within a predetermined acceptable range. The testing apparatus stores in the detector a range representing acceptable sensitivities. When a test is initiated the resulting test output is compared to the sensitivity range, or its representation, and a warning signal is provided when the output is not acceptable. According to one feature, the stored representations of the acceptable range include a maximum acceptable value and a minimum acceptable value, and the warning signal indicates when the output is above the maximum or below the minimum. According to other features, the output signal is periodic at one frequency when above the maximum and at another frequency when below the minimum. The test is initiated by a magnetic reed switch and the results are immediately apparent.

Abstract: Apparatus and a method for detecting glass breaking from an impact. Low frequencies are detected that are characteristics of the glass flexing from the impact, and high frequencies are detected that are characteristic of a) the sound of the impact and b) the glass breaking. An alarm signal is issued when the low and high frequencies occur in a predetermined sequence, and have appropriate durations, that are characteristic of glass breaking events. More specifically, the alarm sounds only when low frequencies are detected not before the high frequencies are first detected but within a predetermined time period after the first detection of the high frequencies.

Abstract: A process and apparatus are provided for calibrating an individual smoke detector prior to installation so its sensitivity can be determined easily throughout its useful life. Representations of detector output signals are stored in the detector prior to installation, preferably at the time of manufacture, and used later for determining the sensitivity of the detector. The signals may represent alarm and clean-ambient conditions, or one of such conditions and the difference between them. During monitoring of the detector, after its installation, a new reading of a corresponding signal under clean-ambient conditions is sampled and the differences before and after installation are compared to determine the sensitivity of the detector when it is monitored. The detector includes electrical contacts from which a representation of detector sensitivity is available for monitoring with an external electrical probe, such as a common voltmeter.

Abstract: A camera includes a film metering mechanism that controls longitudinal movement of the film for half-frame exposures. Film movement alternates between a first distance and a second distance greater than the first distance. The first distance defines abutting pairs of exposure frames and the second distance defines a space between adjacent frame pairs. According to more specific features, film movement is controlled by a cam that includes a first section defining the first distance and a second longer section defining the second distance. Still more specifically, the cam is circular, is driven by the film movement, and includes opposed asymmetric lobes, one for the first distance and the other for the second distance. Each frame pair defines a size equal to a standard 35 mm exposure, and the space between pairs also equals the 35 mm standard. The paired frames can be printed in standard equipment without special handling or procedures.

Abstract: A camera including a photoelectric diode operated as an emitter in a first mode and a sensor in a second mode. The camera includes a first circuit that operates the diode to emit visible radiation and a second circuit that operates the diode to sense scene illumination. The diode is switched between the respective circuits selectively to operate in its first and second modes. The first circuit preferably is a timing circuit in a self-timing camera, but also might provide other functions including reduction of red-eye effects. The second circuit preferably is a photometer for controlling exposure.

Abstract: A transmitter assembly is characterized by a buckle including fasteners for holding a strap and the buckle together on an appendage of an individual independent of a transmitter. The buckle also includes latches for attaching the transmitter to the buckle after the buckle is strapped to the individual. An optical fiber running through the strap is held by the fasteners with the ends of the fiber in predetermined positions relative to the buckle. The transmitter covers the strap fasteners, rendering the fasteners inaccessible to the individual, and aligns an emitter and sensor on the transmitter housing with the ends of the optical fiber in the predetermined positions. The ends of the strap are aligned adjacent one another by the buckle, so the buckle adds little to the length of the strap, permitting length measurements without considering the buckle contribution.

Abstract: A camera is provided with alternative mounting structures, one for an extensible flash and another for a fixed flash. One of the mounting structures is used for securing and aligning a selected alternative extensible or fixed flash device. The other is covered by a camera casing. The casing defines first and second apertures aligned with the first and second mounting structures, respectively. The first aperture provides access through the casing for mounting the extensible flash assembly on the first mounting structure and the second aperture permits passage through the casing of illumination from the fixed flash assembly.

Abstract: Apparatus for determining when a moving vehicle passes a fixed point characterized by a magnetic field. The apparatus includes first and second magnetic-field sensors spaced apart on the vehicle for producing first and second outputs when the sensors move in the magnetic field past the point. The outputs are validated based on the time span between the outputs and the spacing between the sensors. According to certain more specific features, the fixed point is a magnetic buoy, the vehicle is a boat expected to move past the buoy at a speed within an acceptable range, the first and second magnetic-field sensors are electrical coils spaced apart a known distance in the direction of movement, and the validating means uses the sensor spacing and the acceptable range for validating the outputs. According to other features, the elapsed time for the vehicle to travel between two fixed points is determined using only validated outputs.

Abstract: A personal security system includes a test feature for end-to-end testing. A portable transmitter produces an emergency signal including a personal identification number and an auxiliary code. The auxiliary code may be a test bit which, when set, indicates that the emergency signal was activated in a test mode and that an emergency condition did not exist. Activation of the test mode is accomplished by the same systems required to activate the emergency signal to provide full testing. The transmitter is part of a security system including a plurality of portable transmitters and fixed receivers. The transceivers issue either an alarm activating signal or a test signal depending on the test bit in the auxiliary code. A successful test is discernible to the user from the vicinity of the transceiver.

Abstract: A portable transmitter produces an emergency signal including a personal identification number and an auxiliary code. The auxiliary code may be a test bit which, when set, indicates that the emergency signal was activated in a test mode and that an emergency condition did not exist. Activation of the test mode is accomplished by the same systems required to activate the emergency signal to provide full testing. The transmitter is part of a security system including a plurality of portable transmitters and fixed receivers. The transceivers issue either an alarm activating signal or a test signal depending on the test bit in the auxiliary code. A successful test is discernible to the user from the vicinity of the transceiver.

Abstract: Apparatus and a method for detecting glass breaking from an impact. Low frequencies are detected that are characteristics of the glass flexing from the impact, and high frequencies are detected that are characteristic of a) the sound of the impact and b) the glass breaking. An alarm signal is issued when the low and high frequencies occur in a predetermined sequence, and have appropriate durations, that are characteristic of glass breaking events. More specifically, the alarm signal is issued only when the detected low frequencies last for a minimum duration on a sliding scale related to their magnitude. Weaker signals must last longer.

Abstract: An intrusion detection system, including a microwave device and a light emitting diode, is controlled to alternate their operation so the diode is off and not conducting when the microwave is transmitting. During a period when the LED would otherwise be on to indicate some state of detection, it is cycled off to remove its influence from the microwave transmission and reception. The microwave transmissions are intermittent with relatively long intervals between short transmissions. The diode is switched on during the long interval and off during the transmissions, giving the appearance of a diode that it is always on. The invention has particular utility in apparatus including dual independent channels for detecting intrusion and including one or more light emitting diodes that are energized to indicate the state of one or both channels.

Abstract: A film cartridge is provided with an internal mechanism for engaging and pulling a leading end of film from a roll to extend the film through a cartridge exit port. A one-way clutch, including a rotational element captured in a ramped cage, moves in one direction to capture the film between the ball and cage and advance the film through the exit. Movement in the opposite direction releases the film and repositions the clutch for the next advance. Still more specifically, the cartridge includes a second and opposite working one-way clutch for preventing premature retraction of the film. A release mechanism is employed for disabling both clutches when desired for intentional rewinding.

Abstract: In a glass break detector, noise is removed by averaging the signal before it is analyzed for the characteristics that typically accompany glass breaking events. Low frequency signals, associated with glass flexing before it shatters, are isolated from repetitive or symmetrical noise in the same frequency range to increase the signal-to-noise ratio of the detector, improving sensitivity to valid glass breaking events and reducing false alarms.

Abstract: A personal security system includes signaling transmitters and receivers for detecting the transmitted signals. The receivers provide an output representing the received signal strength, which is used in combination with the position of the receiver for locating the point of transmission. All of the transmitters are substantially identical, at least in their transmission characteristics and transmitted signal strength, but include a first portable set of transmitters intended to be carried by subscribers, and a second fixed set of transmitters associated with the receivers. The fixed transmitters are actuated one after another and the receivers are polled to record received signal strength after each transmission from each receiver. The results permit comparisons with expected values, between receivers and over time.

Abstract: A smoke detector includes a dark chamber surrounded by a peripheral wall structure having a plurality of nested vanes. The second element of each vane is shorter than the first, and intersects the first element intermediate its ends at an acute angle. Adjacent vanes define a tortuous path that requires a minimum of three, and in most cases four, reflections for light to reach the inside of the chamber. Adjacent vanes define twisted channels leading from outside the chamber into the chamber for blocking light without substantially restricting the flow of air. The channels each include an outer section that extends in a direction toward the center of said chamber to define a channel entrance that admits airborne smoke with approximately equal resistance from opposite directions. The channels also define second and third sections that bend inwardly from the entrance toward said chamber, first in one direction and then sharply in another direction.

Abstract: Apparatus and methods are provided for separating photographic film strips, adhered to a splice, by restricting movement of the splice and then pulling the film strips longitudinally in opposite directions. According to one feature, the splice adhesive is heated until it softens, preferably with a hot shoe applied against the splice under pressure. According to other features a space is left between the ends of the film strips when they are spliced together, and the splice is engaged from both sides while the film strips are pulled apart. Still more specifically, according to another aspect of the invention, a carrier or splice pick-up web is provided for removing the splices from the area and for holding the removed splices in a manner particularly convenient for disposal.