EP1494186A1

EP1494186A1 - Audio alarm device

Info

Publication number: EP1494186A1
Application number: EP03014949A
Authority: EP
Inventors: Wolfgang Freitag; Holger Zahn
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2003-07-01
Filing date: 2003-07-01
Publication date: 2005-01-05

Abstract

At a method for providing predefined audio signals in response to a detected condition, said audio signals stored in a memory [10], said apparatus comprising a microcontroller [12] and audio output means, said memory [10] comprising said audio signals stored in digital form, and said microcontroller [12] comprising a processor and on-chip peripheral [26] it is intended to receive at said processor detector signals indicating a changed condition, to select from said memory [10] an appropriate audio signal associated with said changed condition, to retrieve a delta modulation of said audio signal from said memory [10], to set a duty cycle for a pulse width modulator by a time unit [30], said modulator [28] and time unit [30] being integral on said on-chip peripheral [26], to modulate said audio signal by said modulator [28] so as to produce a digital representation of said audio signal, to transmit said digital representation to a buffer [34] integrated on said on-chip peripheral [26], and to transmit said digital representation to said audio output means for analog reproduction [24] of said audio signal.

Description

The present invention relates to a method for providing predefined audio signals in response to a detected condition, said audio signals stored in a memory, said apparatus comprising a microcontroller and audio output means, said memory comprising stored audio signals in digital form, and said microcontroller comprising a processor/controller and on-chip peripheral.
Audio alarms alert human operators to changed conditions. Such conditions may not always be apparent to the operators, but may still impact the operators activities. In the case of motor vehicles for example, such changed conditions may range from road conditions, to objects in the proximity, to operating speed.
Traditional audio alarms generate a tone or play language in response to a detected changed condition. The tone or language is usually prerecorded and/or stored in digital form into a memory 10 for later retrieval. The coordination of changed condition detection, selection of appropriate language and audio playback is an expensive proposition given the amount of equipment involved. For example, the retrieving of stored digital audio and playback requires a certain minimum processing speed and supporting hardware. Such are susceptible to external adverse influences including shock, environment and the like along with requiring a certain power consumption. The actual processing speed and equipment therefore varies upon application and is generally known in the art. A problem therefore exists in bringing audio alarms to the general mass-consumer market in an inexpensive and robust form.
The task or solution of the present invention is to bring to market a low cost mass produceable apparatus via an inventive method such that the inventive apparatus may be integrated into detection systems to as to produce predetermined audio alarms in response to particular detected changed conditions. The present apparatus will find application in motor vehicles, such as automobiles, trucks, aircrafts, ships and the like. Other applications may include any environment wherein changed conditions play a role for the human operator.
The task or solution of the present invention is accomplished by the elements and method steps set out in claim 1, namely, receiving at said processor detector signals indicating a changed condition, selecting from said memory 10 an appropriate audio signal associated with said changed condition, retrieving a delta modulation of said audio signal from said memory 10, setting a duty cycle for a pulse width modulator 28 by a time unit 30, said modulator 28 and time unit 30 being integral on said on-chip peripheral 26, modulating said audio signal by said modulator 28 so as to produce a digital representation of said audio signal, transmitting said digital representation to a buffer 34 integrated on said on-chip peripheral 26, and transmitting said digital representation to said audio output means for analog reproduction 24 of said audio signal.
The present invention will be described with respect to the drawings which depict the following.
Figure 1: depicts a block diagram of the present invention.
The present invention comprises a method and apparatus for generating an audio alarm. The alarm may comprise any audio alerts, including at least one language, tone, and/or combinations thereof (hereinafter alerts). As depicted in figure 1, the alerts are stored in appropriate registers of memory 10. The alerts are stored in a delta modulated digitized form. Delta modulation refers to a known method of analog to digital conversion wherein the analog signal is approximated or sampled by a series of segments. The sampling rate is 32,000 times per second. Each segment is comparable to the original analog wave. A determination is made whether the approximated segment has a relative increase or decrease in amplitude with respect to a successive sample. Any change is indicated in a successive bit (0 or 1). If there is no change, the previous bit is repeated. Accordingly, the analog signal is sampled, digitized and stored into memory 10 along with the duty cycle, command, and all the information need to go through the command (locate the appropriate register in response to particular changed conditions, retrieve data, etc, herein a look up table may be employed).
Memory 10 is depicted as being external from microcontroller 12, however, in alternative embodiments, the memory 10 may be internal to the microcontroller 12. Memory 10 is in electrical communication 14 with the microcontroller 12, such that data may be requested by the microcontroller 12 from the memory 10, retrieved, and sent to the microcontoller from the memory 10. Programming of the microcontroller 12 and facilitating of information retrieval from memory 10 is known in the art. A detector 16 is in electrical communication with the microcontroller 12. Detector 16 is a generic detector implemented to detect condition changes as may be effected on a case by case basis. The detector 16 must simply convey to the microcontroller 12 either a change of condition or a current condition (as such, any display capable of such output is operable with the present invention). In the latter case, the microcontroller 12 is further programmed to detect changes in the detected condition, determine if an alert situation is present and initiate the audio alert sequence. In the former case, the microcontroller 12 is already provided with the signal to initiate the alert sequence. In alternative embodiments, the detector 16 may comprise an intelligent detector capable of interacting with the microcontroller 12 to provide select information.
The microcontroller 12 outputs a digital signal to an amplifier 18, which amplifies the digital signal and directs it to an audio output means. Audio output means may comprise a speaker 20, acoustic transducers, and the like. The audio output means is depicted as being grounded 22 and the audio output is depicted as a sound wave 24 to person P.
The microcontroller 12 includes a processor for facilitating operation of the on-chip peripheral 26 and communication between microcontroller 12 and on-chip is facilitated by means known in the art. The on-chip peripheral 26 comprises a pulse width modulator (PWM) 28, time unit 30, AND gate 32 and buffer 34. The on-chip peripheral 26 will be discussed by way of operation. Initially a change of condition will be detected by the detector 16. For example, it has become night time and it is time to activate the headlights. The appropriate register is activated and the appropriate alert signal is generated. The PWM is activated for each segment of the alert signal generated by the delta modulation (discussed above) and produces (modulates) a square wave with a matching duty cycle. The time unit 30 ensures that a sufficiently high clock frequency is produced so as to match the delta sampling rate. This is further facilitated by AND gate 32. Once each segment of the alert signal (waveform) is modulated, a digital signal of the analog alert signal is produced. The digital signal is passed to the buffer 34, wherein small spikes, parasitics and the like are filtered out. The buffer 34 may comprise a high frequency filter. The buffered digital signal is then amplified by amplifier 18 and reconverted back into an audio signal at speaker 20.
As such, the on-chip peripheral 26 makes mass production possible, while reducing the costs of individual components and their operating means. With reduced components comes better protection against the elements. Furthermore, as any display detector unit capable of output is operational with the present invention, the application of the present invention is increased.

Claims

A method for providing predefined audio signals in response to a detected condition, said audio signals stored in a memory [10], said apparatus comprising a microcontroller [12] and audio output means, said memory [10] comprising said audio signals stored in digital form, and said microcontroller [12] comprising a processor and on-chip peripheral [26],
characterized in that

receiving at said processor detector signals indicating a changed condition,

selecting from said memory [10] an appropriate audio signal associated with said changed condition,

retrieving a delta modulation of said audio signal from said memory [10],

setting a duty cycle for a pulse width modulator [28] by a time unit [30], said modulator [28] and time unit [30] being integral on said on-chip peripheral [26],

modulating said audio signal by said modulator [28] so as to produce a digital representation of said audio signal,

transmitting said digital representation to a buffer [34] integrated on said on-chip peripheral [26], and

transmitting said digital representation to said audio output means for analog reproduction [24] of said audio signal.
The method according to claim 1, wherein said buffer [34] smoothes small spikes and parasitics from said reproduced audio signal [24].
The method according to claims 1 and 2, wherein said buffer [34] comprises high frequency filter means.
The method according to claims 1-3, wherein said microcontroller [12] further comprises a look up table and said processor selects said appropriate audio signal.
The method according to claims 1-4, wherein said memory [10] is located within said microcontroller [26].
The method according to claims 1-4, wherein said memory [10] is located outside of said microcontroller [26].
The method according to claims 1-6, further comprising an amplifier [18] electrically connected between said buffer [34] and audio output means, said amplifier [18] amplifying said digital representation.
The method according to claims 1-7, wherein said audio output comprises at least one language.
The method according to claims 1-8, wherein said audio output comprises at least one tone.
An apparatus for performing the method according to any one of claims 1-9.