Whelen Engineering Compnay, Inc.

David Dornfeld

Brandon Conlon

Caleb Garrett

A system, method and storage medium for providing an emergency alert includes reading tone, using one or more processors, information and volume level information corresponding to an emergency sound generator from memory coupled to the one or more processors; and controlling, using the one or more processors, an output sound of the emergency sound generator based on the tone information and volume level information. The tone information includes data of frequency variation over a predetermined period, and the volume level information includes data of volume level variation over the predetermined period.

Volume scaling and synchronization of tones

A system, method and storage medium for noise cancellation in a vehicle includes determining a waveform of a first sound wave at a first location, calculating another waveform of the first sound wave at a second location of an operator based on the waveform of the first sound wave at the first location and a first distance between the first location and the second location, generating at least one control signal based on the determined another waveform of the first sound wave at the second location, and generating a second sound wave based on the at least one control signal. A waveform of the second sound wave are formed to cancel out the first sound wave at the second location. The first sound wave is generated by a noise source.

System and method for noise cancellation in emergency response vehicles

A lever operated switch employs an actuating surface and a plurality of tactile switches to generate electrical states corresponding to distinct angular orientations of the lever. The lever extends from a cam having an actuating surface configured to change the state of one switch when the lever is moved between adjacent positions. The cam is reversible, permitting the switch to be mounted on opposite sides of a support with the same lever movement and switch actuation.

Lever switch

An electronic siren emulates the sound of a mechanical siren using a dynamic algorithm and look up tables to generate a series of wave sets, each wave set including one fixed frequency wave and one variable frequency wave. A micro controller stores the algorithm and look up tables and executes the algorithm on command to produce a digital output emulating the mechanical siren. The digital output is converted to an analog signal that is applied to a class D amplifier. A switching power supply provides 70 VDC to the output stage of the amplifier. This arrangement produces 126 dB of sound pressure at a distance of 10 feet from the reverse folded horn speaker. The electronic siren generates little heat and requires only 10 amps of current from the vehicle electrical system.

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Killingworth, CT, United States of America

David Dornfeld