The dual-chamber whistle is a sound producing device that creates a first air flow, a second air flow and a third air flow within the dual-chamber whistle. The basic sound of the dual-chamber whistle is generated by a first turbulence created the interaction of the first air flow and the second air flow. The third air flow also interacts with both the first air flow and the second air flow to create a second turbulence. This second turbulence creates an additional sound called the oversound. While actual patterns of turbulences created in both the first turbulence and the second turbulence are essentially random, the human psychological response to the oversound is to interpret the oversound as an actual call for help. The dual-chamber whistle comprises an intake, an exhaust, and a router which creates a complex air flow.

A motor vehicle comprising a sound emitting instrument for emitting sound comprising an aerophone instrument is disclosed. The aerophone instrument is arranged so as to be constantly invested by an aerodynamic flow corresponding to a forward motion of the motor vehicle, whereby the aerophone instrument is configured to emit at least part of said sound passively through the aerodynamic flow, and an active device configured to actively control at least one property of the sound, characterized by comprising a control apparatus, in turn comprising a mapping to associate a speed of the motor vehicle with a desired value of a variable corresponding to the property, the control apparatus being configured to determine the speed of the motor vehicle, and control the active device as a function of the desired value according to a control law to reduce a deviation between an actual value of the variable and the desired value.

A motor vehicle comprising a sound emitting instrument for emitting sound comprising an aerophone instrument is disclosed. The aerophone instrument is arranged so as to be constantly invested by an aerodynamic flow corresponding to a forward motion of the motor vehicle, whereby the aerophone instrument is configured to emit at least part of said sound passively through the aerodynamic flow, and an active device configured to actively control at least one property of the sound, characterized by comprising a control apparatus, in turn comprising a mapping to associate a speed of the motor vehicle with a desired value of a variable corresponding to the property, the control apparatus being configured to determine the speed of the motor vehicle, and control the active device as a function of the desired value according to a control law to reduce a deviation between an actual value of the variable and the desired value.

A set of two or more whistles. Each whistle of the set sounds differently from each other based on a different type of sound or a different value of a characteristic of sound common to whistles of the set. Sound characteristics may include but not limited to pitch, quality, loudness, and/or duration. Each whistle in the set may be different in appearance from each other in the set. Appearance characteristics may include but not limited to color, numbering, design, light up features, size, and/or shape. Alternatively, the whistles in a set may have a common appearance characteristic, but each whistle may have its own value of the common appearance characteristic. Additional element(s) such as lanyards or mouthpieces may be added to whistles of a set to distinguish them from each other. The set of whistles may be included in a kit having a box for removably storing the whistles.

A set of two or more whistles. Each whistle of the set sounds differently from each other based on a different type of sound or a different value of a characteristic of sound common to whistles of the set. Sound characteristics may include but not limited to pitch, quality, loudness, and/or duration. Each whistle in the set may be different in appearance from each other in the set. Appearance characteristics may include but not limited to color, numbering, design, light up features, size, and/or shape. Alternatively, the whistles in a set may have a common appearance characteristic, but each whistle may have its own value of the common appearance characteristic. Additional element(s) such as lanyards or mouthpieces may be added to whistles of a set to distinguish them from each other. The set of whistles may be included in a kit having a box for removably storing the whistles.

Apparatus, systems, and methods for providing transmission and localized reception of audio, visual, and tactile signaling are taught for a myriad of useful purposes, including embodiments that permit differentiation between selected groups of intended recipients to permit simultaneous use of multiple instances of this technology in close proximity, if desired.

Apparatus, systems, and methods for providing transmission and localized reception of audio, visual, and tactile signaling are taught for a myriad of useful purposes, including embodiments that permit differentiation between selected groups of intended recipients to permit simultaneous use of multiple instances of this technology in close proximity, if desired.

A water-powered residential fire suppression and alarm system is provided. The system comprises a sprinkler head, a water-powered or electrically-powered alarm, a fire-resistant transfer line assembly, and a housing assembly. The sprinkler activates upon excessive heat. The transfer line assembly provides an unclosable channel connecting an existing residential water source with the sprinkler head. The transfer line assembly includes a fire-resistant transfer line connected to a multi-port coupling which connects to the existing water source. The transfer line assembly also provides water to the alarm. The housing assembly has a housing with a vertical span of about 3-12 inches. The sprinkler head and alarm are mounted to the housing assembly and the transfer line assembly is connected to the housing assembly. When water is provided to the coupling and the sprinkler head activates, water flows through the transfer line, activating the alarm.

A water-powered residential fire suppression and alarm system is provided. The system comprises a sprinkler head, a water-powered or electrically-powered alarm, a fire-resistant transfer line assembly, and a housing assembly. The sprinkler activates upon excessive heat. The transfer line assembly provides an unclosable channel connecting an existing residential water source with the sprinkler head. The transfer line assembly includes a fire-resistant transfer line connected to a multi-port coupling which connects to the existing water source. The transfer line assembly also provides water to the alarm. The housing assembly has a housing with a vertical span of about 3-12 inches. The sprinkler head and alarm are mounted to the housing assembly and the transfer line assembly is connected to the housing assembly. When water is provided to the coupling and the sprinkler head activates, water flows through the transfer line, activating the alarm.

A retractable multifunctional dog leash that contains an outer shell, a retractable rope in the outer shell, and a position limiting stopper at a front end of the retractable rope to prevent the retractable rope from completely retracting back into the outer shell. A roller device releasing and retracting the retractable rope is provided inside the outer shell; a sound generator is also provided on the outer shell to generate sound directly. The dog leash is easy to carry and use, and its retractable rope can be easily adjusted to extend and retract as desired