Audible Warning Research Articles

Ultrasonic distance detector

An ultrasonic detector for roadway vehicles comprises an array of electroacoustic transducers mounted on the rear of the vehicle. The transducers are sequentially driven by a transmitter circuit to transmit a pulsed, laterally shifting ultrasonic energy toward an object located behind the vehicle in one of plural regions defined by partially overlapped directivity patterns of adjacent transducers. A receiver circuit is coupled to the transducer array to receive echos returning from the object during the interval between successive beam transmissions. A logic circuit detects the lateral position of and the distance to the object for giving relevant indications on a display unit, the audible tone being variable depending on object distance. An audible warning device is optional.

An ultrasonic signal processor for use in underwater acoustics

An ultrasonic signal processor is described which analyses information from conventional echo sounders fitted to small craft. Although an inexpensive accessory, it includes a number of novel features of value both to hydrographers and fishermen. The features include a high level of quantitative bottom discrimination, a wide dynamic range of fish abundance measurement with fine resolution (including modes for bottom trawling and net ‘flying’), the ability to detect fish close to the sea bottom, and the provision of audible warning systems. One of the features of the device is that while exploiting original scientific approaches, it permits these to be used in such a way as to augment, confirm and extend the professional experience of the individual fisherman.

An audible train warning for track maintenance personnel

British Rail track maintenance staff currently use a portable warning device to provide audible warning of approaching trains. The audible signal comprises a train warning signal, which is continuous and the same signal broken into a series of discrete ‘bleeps’ to signify that it is safe to work. If the audible signal ceases entirely when bleeping then men could continue to work without protection. The study reported in this paper was in two parts. The first part, a laboratory study, compared response times to the sudden disappearance of the bleeping signal for four different lengths of interval between bleeps. The second part, a field study, sought to establish how operational conditions influenced response times for the interval with the shortest response time in the laboratory. The main recommendation from the study was that the interval should be shortened from the 7 s specified at the time the study was undertaken, to 2 s, in order to facilitate quicker responses to the absence of the bleeping signal.

Industrial control for audible electronic warning system

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Effectiveness of audible warning signals for emergency vehicles.

Twenty-four subjects engaged in a simulated driving task detected audible warning signals of the sort commonly used by emergency vehicles. The simulated driving task, carried out in an instrumented car under computer control, included steering toward alternately illuminated fender lights and maintaining a constant speedometer reading. The required detection response was depression of the brake pedal. To a first approximation, signals of equal detectability were equally effective in eliciting braking responses.

Load cell: a device to monitor weight bearing for lower extremity amputees.

The PRS-Moore Load Cell for use in immediate postoperative prosthetic fitting for above- and below-knee amputees is described. The design incorporates an audible warning device which will sound whenever the wearer applies more than the predetermined weight on the affected limb. The device is easy to use in a clinical setting and can be incorporated into any endoskeletal pylon. The cost per unit is approximately $125, and the cell can be reused for successive patients.

A ventilation monitor during demand flow CPAP

A commercially available pressure alarm monitor has been suitably modifed to provide audible warning of significant and critical changes in the respiratory patterns during demand flow spontaneous ventilation with CPAP. The alarm retains its originally intended function, i.e. detection of ventilation failure during controlled or assisted ventilation or both, with or without PEPP.

An evaluation of IL-404 oxygen alarm monitor.

The accuracy of the IL404 oxygen alarm monitor has been tested against oxygen/nitrogen mixtures of known composition. The effects of inhalational anaesthetic agents and of changes in flow rate, PCO2 and humidity have also been investigated. The instrument was found to be sufficiently stable and accurate for clinical use and was unaffected by the presence of volatile anaesthetics, change in gas flow rate and the presence of nitrous oxide, carbon dioxide or water vapour. The instrument incorporates an efficient alarm system which gives both audible and visible warning should the oxygen concentration fall or exceed pre-set limits.

Sensory Aids for the Blind Using Acoustics

Blind people long have used acoustic cues and echoes, plus oral descriptions or reading, Talking Books, or recordings. To supplement a long cane or dog, an experimental ultrasonic sensor warns of objects at chest height. Binaural ultrasonic “spectacles” sense the environment and aid mobility. A laser cane using optical triangulation provides audible signal of overhead objects, major drops, and objects ahead of the user. LED “spectacles” provide audible warning of an object at head height. The ultrasonic spectacles provide comprehensive but complex signals; the other devices provide go-no-go information. For reading, the latest direct translator of letter shape to tone patterns is a portable, relatively inexpensive stereophonic aid, with bass boost in the left ear and treble in the right. A more complex optical character recognizer, also intended for individual ownership, uses spelled-speech output, coalescing into wordlike groups at higher speeds. Synthesis of easily understood English speech from letter recognition, automatic grapheme-phoneme dictionary, and rules for intonation and inflection will require computer-based library-type operation. These experimental devices have reached user trials. Further clinical studies and education of teams in prescription and training methods should lead to wide use.

Harmonic radar helps autos avoid collisions

In the foreseeable future, a radar system immune to clutter through use of a special reflecting tag could aid the the driver to maintain a safe distance between the cars, the closing rate, and the driver's ground speed. To eliminate the clutter and blinding problems, a system has been designed that uses an harmonic radar concept. An experimental harmonic radar collision avoidance system has been built using an RCA transferred electron oscillator power source. The measurement of distance was quite repeatable and of adequate accuracy for highway use. In the automatic braking system once the alarm is given, the brake pedal is automatically depressed by a force that increases linearly with time up to maximum pressure until the alarm is removed. The force is then removed linearly with time. The harmonic radar system will reject all blinding signals that it receives other than the second harmonic of its transmitted frequency. The possibility of a false alarm from crosstalk interference is reduced with harmonic radar. The system is adaptable to integrated and printed-circuit techniques. It operates in regions of the frequency spectrum which are still underutilized and spectrum space can be set aside for its future use. The average power density in the immediate vicinity of the antenna is 0.2 mW/cm2. When a dangerous driving situation is detected, an audible warning is sounded and a warning light is flashed. The harmonic radar system provides protection from certain types of rear-end collisions; those where the car in front is in line with the following car. Vehicles that are stopped, but not parallel to the center line, will not be seen by the following car because of the purposefully narrow beam of the passive reflector./SRIS/

Performance analysis of an infrared pilot-warning indicator system

An optical-infrared concept is described having applications to a simple, low cost pilot-warning indicator. The system required ultimately should be capable of providing the aircraft pilot with an audible warning and a visual presentation which would give both elevation and relative bearing information on other aircraft. This information would be relative to a fixed reference such as the flight path or the longitudinal axis of the aircraft. The concept investigated is not meant to compete with the automatic collision avoidance system, but should be thought of primarily as a simple and relatively cheap means of providing enhanced collision avoidance capability for general aviation aircraft. The system should be capable of multitarget detection at ranges of at least 2 to 5 miles, with an audible alarm, and should provide the pilot with the directional positions of those other aircraft. With these simplified requirements a cooperative pilot-warning indicator system is being developed, based upon the detection of infrared energy emitted by a light source placed on each aircraft. System concepts will be described, based upon the feasibility of the source-detector combinations investigated. These concepts will ultimately have to consider omnidirectional detection of aircraft equipped with xenon lights, and display concepts applicable to this approach need to be further developed.

Acoustic Maintenance Aids

By means of monitoring audible/vibrational signals, two methods have been developed that make it possible to detect, on an incipient basis, the failure of a component, mechanism or machine. The first approach involves real-time monitoring of a system via permanently installed transducers. As part of this scheme, a computer system is used to analyze the transducer signals so as to provide visual or audible warnings that a malfunction might possibly occur. The second technique revolves around a specially developed frequency/amplitude detection unit capable of scanning a transducer signal over a very wide frequency/amplitude band. The feature that makes it unique is its ability to classify the amplitude at any one frequency as being indicative of normal, marginal, or defective operation. Both of the methods were developed to compensate for the inadequacies that present-day maintenance technology provides. While the concept of signature recognition as a maintenance aid is not new, the specific techniques developed are unique and suggest an approach to failure prevention that might be particularly attractive to users of data processing equipment.

Transistorised, Battery-Operated ‘Door-Post’ Radiation Alarm Monitor, with Audible and Visual Warnings

Transistorised, Battery-Operated ‘Door-Post’ Radiation Alarm Monitor, with Audible and Visual Warnings

A Pocket Radiation Monitor

It has been appreciated for some time, that there is a need for a device which can warn radium ward nursing staff when they are in a relatively high radiation field. Such a monitor, giving an audible warning in the form of a series of clicks, was described by Watson (1960). Current miniaturisation techniques have made it possible to build a small sophisticated instrument, giving a more insistent warning, which takes the form of an intermittent note of about 2 kc/s, the duration increasing as the radiation intensity rises.

Equipment and Processes

Liquid monitor control. Photronic Controls Ltd. manufacture a new instrument which is designed to monitor the flow of a liquid in a pipeline and to provide an audible and visual warning when the density of the liquid varies from a pre‐set point. This operation is of particular value in controlling effluent discharges into rivers and also to control processes involving the movement of liquids as in breweries and soft drink manufacture.

Focal-point protection system for power reactors

The development of power-reactor electrical protection circuits and current design practice are briefly discussed, and the performance of these systems is considered in relation to ideal safety concept requirements.A new focal-point protection design is proposed for emergency shut-down. This offers a basically simple, highly reliable, solid-state protection system and provides continuous one-out-of-one tripping for all trip facilities.Continuous cycle testing of all trip circuits, from the primary trip amplifier or transducer to the hold-circuit output, is carried out automatically. The detection of a trip-unit fault, or malfunctioning of the interrogator/responder circuits, produces an audible warning and visual indication of the equipment involved, and at the same time isolates the faulty circuit, without prejudice to the in-line protection, until repairs have been effected.An analysis of focal-point system protection integrity is made. It is demonstrated that any significant in-line and fail-danger component fault will be detected, located, removed and replaced within 3 ms and any fail-safe component fault will be detected and removed from the in-line protection circuits within 20 ms of occurrence without producing a false reactor shut-down trip. The design of the trip-unit equipment is discussed.

Focal-point protection system for power reactors

The development of power-reactor electrical protection circuits and current design practice are briefly discussed, and the performance of these systems is considered in relation to ideal safety concept requirements.A new focal-point protection design is proposed for emergency shut-down. This offers a basically simple, highly reliable, solid-state protection system and provides continuous one-out-of-one tripping for all trip facilities.Continuous cycle testing of all trip circuits, from the primary trip amplifier or transducer to the hold-circuit output, is carried out automatically. The detection of a trip-unit fault, or malfunctioning of the interrogator/responder circuits, produces an audible warning and visual indication of the equipment involved, and at the same time isolates the faulty circuit, without prejudice to the in-line protection, until repairs have been effected.An analysis of focal-point system protection integrity is made. It is demonstrated that any significant in-line and fail-danger component fault will be detected, located, removed and replaced within 3 ms and any fail-safe component fault will be detected and removed from the in-line protection circuits within 20 ms of occurrence without producing a false reactor shut-down trip. The design of the trip-unit equipment is discussed.

Audible warning device for use on Boyle's apparatus

AnaesthesiaVolume 18, Issue 1 p. 109-110 Free Access Audible warning device for use on Boyle's apparatus C.J. TREVAIL–ARCHER, C.J. TREVAIL–ARCHERSearch for more papers by this author C.J. TREVAIL–ARCHER, C.J. TREVAIL–ARCHERSearch for more papers by this author First published: January 1963 https://doi.org/10.1111/j.1365-2044.1963.tb13716.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume18, Issue1January 1963Pages 109-110 RelatedInformation

PRODUCTS and PROCESSES: PROVIDING INDUSTRY WITH THE MEANS TO COMBAT CORROSION

Audio Thickness Gauge. Thickness of sprayed zinc and aluminium coatings can be rapidly checked with the new Metallisation Ltd. audio thickness gauge. The instrument has an exploring head which may be moved quickly over the coated surface and, having been set to indicate a minimum thickness, it gives an audible warning of areas which are below the required thickness. Accurate test specimens are used to set the gauge to any desired thickness between 0.002 to 0.012 in. The set is completely portable, fully transistorised and is unaffected by magnetic fields or stray magnetism. CT 1200

A personal -radiation monitor with audible warning device

A prototype personal γ-radiation monitor is described, which uses an electrometer valve and transistor alarm circuit to give an audible warning to the wearer on receipt of a tolerance dose of γ-radiation. The insulation requirements of the valve and chamber circuits and the design of the alarm circuits are discussed, particular attention being paid to ease of checking and fail-safe features. It is concluded that the desired performance is consistently realizable in the design presented, a dosage accuracy of the order of ±5% being achieved.