GB2346042A

GB2346042A - Sound monitoring apparatus

Info

Publication number: GB2346042A
Application number: GB9926491A
Authority: GB
Inventors: Christopher Rycroft
Original assignee: Lindam Ltd
Current assignee: Lindam Ltd
Priority date: 1998-11-19
Filing date: 1999-11-10
Publication date: 2000-07-26
Also published as: GB9926491D0

Abstract

A monitor system comprising a sound detecting device, a signal transmitting mean for transmitting a signal indicative of the sound heard, receiving device which can be positioned remote from the sound detecting device for receiving the transmitted signal and speaker means and/or visual means for representing the sound to the user. In addition, the system incorporates a synthesiser and microprocessor control system which allows selection of one or a number of a range of frequency values stored in the system to be used to transmit the signal from the signal emitter to the signal receiver. The microprocessor control system also allows the channels to have security codes attached, thereby reducing cross interference from other systems. The signal may be digitally modulated.

Description

Monitoring Apparats and System The invention to which this application relates is monitoring apparatus for use in the monitoring of sounds in a location remote from the position of a person who can hear the sounds reproduced by the apparatus. The apparatus is of particular, but not necessarily inclusive, use in the listening to babies and small children by parents, such as for example when the babies or small children have been put to sleep in their room and the parents wish to listen out for disturbance or noise from the child when they are in another room of the house.

Listening and monitoring apparatus is well known and typically comprises a transmitter which is placed in the room where noise is to be monitored and a receiver which is placed in the vicinity of the person or persons who wish to listen to the noise and/or see a display indicative of the noise and it should be noted that reference hereon in to listening to the noise should also incorporate of a visual display or representation of the noise being provided. The most common type of apparatus is one which emits a signal from the transmitter via a low range FM frequency and which is received by the receiver and transmitted by a speaker mounted in the receiver.

A problem with conventional transmitters and receivers of this type is that the functions of the same are limited due to the relatively simple technology which is used. In addition, the frequency ranges and frequency levels which are acceptable and available for use by this apparatus varies from country to country. Thus, different countries have different frequency requirements and restrictions and different frequency availabilities. It is therefore currently necessary for the apparatus to be manufactured for sale and use in specific countries.

A further problem is that cost restraints typically limit the number of crystal controlled channels available, typically two. The restrictions to two channels can give rise to interference from similar products in close proximity such as in adjacent houses.

The aim of the present invention is to provide apparatus in a form which allows the same to be operable with a number of operating parameters which can be selected in accordance with the country in which the same is to be used by the automatic or manual selection of operation characteristics. A further aim is to provide a monitor system which has added functionality and can, if required, provide additional information to the user of the system. A yet further aim of the invention is to provide a means to enable a larger number of channels to be made available thus reducing cross interference.

In a first aspect of the invention there is provided a noise monitoring system, said system comprising a sound detecting device including a digital transmitter for transmitting a signal indicative of detected sound, a receiving device which can be positioned remote from the sound detecting device and including means for receiving the transmitted signal and speaker means and/or a visual display for reproducing the detected sound and wherein the system incorporates a synthesiser and microprocessor control system to allow the selection of one, or a number, of a range of frequency values which is/are to be used to transmit the signal from the sound detecting device to the receiving device.

In one embodiment the noise signal frequency values in the range are all FM low frequency values.

In a further feature of the invention the control system allows control of power management of the power supply to the device, battery strength indication means and signal strength indication means either alone or in combination. It may also provide the means to sense the room temperature in which the signal emitter is positioned and allow this information to be transmitted to the signal receiver.

A Liquid Crystal display (LCD) is preferably used to indicate all functions. For example, battery power, signal strength, channel number or frequency, temperature and/or a time clock can be set and displayed on the LCD. The temperature and clock functions can be further selectable as Celsius or Fahrenheit and 12 hour or 24 hour respectively.

In a further aspect of the invention there is provided a noise monitoring system comprising a sound detecting device including a digital signal transmitting means for emitting a signal indicative of the sound heard, a receiving device which can be positioned remote from the transmitting means for receiving the emitted signal and speaker means for relaying the reproduced noise to a listener and wherein the system incorporates a synthesiser and microprocessor control system and said signal is carried by one of a number of selectable frequencies on one of a number of selectable channels, said frequencies and/or channels operable with security code so that the transmitted signal can only be received and processed by the receiving device if it is set to operate with a matching security code, thereby reducing cross interference from other apparatus.

In one embodiment, the microprocessor control system allows crystal controlled channels to have security codes which control operation of the device. The security codes ensure that a signal can only be received by the receivr when the signal comes from a transmitter with the same security code, thereby reducing cross interference from other apparatus or systems.

In one embodiment of the invention the microprocessor can allow at least 10 security codes per crystal channel. For example, using 2 crystal controlled channels, 20 secure channels can be provided.

This enables a larger number of available channels to be used with the system.

In a further embodiment, the system includes a setting to allow the user of the system to store all of the available frequencies for the transmission of the signal. However, not all of the available frequencies can be used in all of the countries where the monitoring system may be used and so, in one embodiment, the microprocessor is adapted to select from the settings the appropriate frequencies for transmission of the signal upon input of country information or a code dependent on the country in which the monitor system is to be used. Alternatively, and/or in addition, manual control means can be provided to allow the manual selection of a country in which the monitoring system is to be used and whereupon the manual selection causes the particular frequencies for that country to be selected.

In one embodiment the synthesiser holds all frequencies which are available for low power transmissions within the range of 26 to 868MHz, and normally the frequency settings available for each designated country will be factory set as not all the countries have the same number of signal channels available for use, or bandwidth range.

In one embodiment, the selection of the country, and so the frequency range for that country, is selected by the manufacturer of the device or the company responsible for onward sales, and the end user of the system is not able to select the country. Typically the country can be selected using the entry of code numbers, each of which is related to a specific country and frequency range for that country, which information is held in the system memory.

Typically, in use, the signal transmitter and sound detecting means, such as a microphone, are provided in the same housing and said housing may be provided with a power supply or power cells and is positioned in the vicinity of the person or animal which is to be listened to. The signal receiver and speaker are also typically mounted in the same housing and are provided with power supply or power cells and an antenna to receive the transmitted signal. Said receiver housing can be located in the vicinity of the person or persons wishing to listen to the person or animal in the other room.

It is envisaged that the invention is of particular advantage for use as a baby monitoring apparatus in which a baby or small child can be listened to by parents or carers who are not necessarily in the same room as the child or baby.

Thus in accordance with the invention there is provided a noise monitoring system for use in a premises comprising a sound detecting device including a microphone for detecting a sound in the vicinity of the device, digital or analogue signal transmitting means for transmitting a signal indicative of the sound in a digital or analogue format, a receiving device which can be positioned remote from the sound detecting device and including a means for receiving the digital or analogue transmitted signal and speaker means and/or visual display means for processing and reproducing the signal via the speaker means and/or visual means and wherein the system incorporates a synthesiser and microprocessor control system to allow the selection of one or a number of a range of frequency values stored in the system to be used to transmit the signal from the signal transmitter to the signal receiver.

In a further aspect of the invention there is provided a noise monitoring system comprising a sound detecting device including a sound detection means for detecting sound in the vicinity of the device, signal transmitting means for transmitting a signal indicative of the sound, a receiving device which can be positioned remote from the sound detecting device and including a means for receiving the transmitted signal and speaker means and/or visual display means for processing and reproducing the signal via the speaker means and/or visual means and wherein the transmitted signal is encoded into a digital format at the sound detecting device, transmitted and decoded at the receiving device by a microprocessor system.

The use of the digital transmission formats allow the efficient control of the data which represents the sound which is sensed and also allows increased accuracy in the data which is transmitted from the sound detection device to the receiving device. The use of the microprocessor to encode the data prior to transmission into a digital format ensures an improved quality of signal which can be reproduced over the speaker of the receiving device.

Specific embodiments of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 illustrates an elevation of a first embodiment of the signal transmission apparatus hereinafter referred to as a transmitter; Figure 2 illustrates an elevation of the signal receiving apparatus hereinafter referred to as the receiver; and Figure 3 illustrates an end view of the signal receiver of Figure 2.

Figure 1 illustrates a sound detecting device 2 according to the invention which is, in use, positioned in the vicinity of the person or animal to be listened to and for the purposes of this example, a child is to be listened to. The child may, for example, be in a cot asleep. The sound detecting device is provided with sound listening or sensing means 4 in the form of a microphone which allows any noises made by the child to be detected. A signal is transmitted via a transmitter (not shown) within the housing 6 of the sound detecting device which represents the sound heard and said signal is transmitted and carried using a selected FM radio frequency. The device can either be battery powered or may be powered by mains.

In the example shown the sound detecting device also includes a temperature sensor which allows the temperature in the vicinity of the device to be sensed and a signal equivalent to the temperature value can also be transmitted via the FM frequency. The sound detecting device is provided with a display 8 which can be selected to show the temperature, the particular frequency channel which is being used to transmit the signal and/or a battery condition indicator 10. The display can be selected by using the select button 12. The device may also be provided with a comfort light 14 which provides subdued light in the vicinity of the device.

Turning now to Figure 2, there is illustrated a receiving device 15 according to the system of the invention which includes an antenna 16 to receive the transmitted signal from the sound detecting device of Figure 1. The receiver housing 17 is provided with a display 18 which can be selectively controlled to display battery power, temperature, the channel used to transmit the signal and may also include a display 20 to display the strength of the signal from the transmitter. There can also be provided a mute indicator which indicates whether the receiver is operating with the speaker functional or whether it is simply a visual display. There is also provided an LED visual sound indicator 22 which gives an indication to the persons listening or watching the device of the relative level of the sound detected. The display 18 can be changed using the select button 24. The receiver is also provided with a volume control 26 to allow the volume of sound which is transmitted through the speaker 28 to be selected. Again, the receiver may be powered by batteries or by mains supply.

The receiver device and sound detection devices include a microprocessor and synthesiser based control system. The synthesiser 15 typically crystal controlled for transmission and has stored therein all of the available frequency range channels which can be used to transmit the signals for low power transmissions of the type used by the system, and typically hold all the frequencies available within the range 26-868MHz. However, countries in which the system can be used do not always have all or the same frequencies or channels available for use. In one embodiment at the time of manufacture or prior to sale, the devices can be set for operation in a particular country by entering a code which is equivalent to a particular country. Upon the entering of the code, the synthesiser will be directed by the microprocessor to operate at a predetermined frequency or allow the selection of one of a range of frequency channels which are appropriate for that particular country and allowable in that particular country. This therefore means that when the product is sold in the designated country, it can immediately be used and allows the manufacturer of the device to manufacture one common product for use in a whole range of countries which can then be factory set for a particular country if required. This is in contrast to having to manufacture separate units with separate frequency channels of operation for particular countries which is time consuming and expensive to manufacture.

In addition, the microprocessor based control system provides the ability to add security codes for frequencies on each crystal channel frequency. These codes are known as CSCTM (Channel Security Codes). Typically two crystal channels allow 20 CSC to transmit the signal for low power transmissions of the type used by the system and means that the signal transmitted can only be received by a receiver device with a matching security code.

The temperature is measured at the transmitter and displayed on the Liquid Crystal Display of the transmitter. This temperature is transmitted at intervals directly to the receiver, which displays it on its Liquid Crystal display, giving a remote indication of temperature change in the transmitter location.

Claims

Claims : 1. A noise monitoring system, said system comprising a sound detecting device including a transmitter for transmitting a signal indicative of detected sound, a receiving device which can be positioned remote from the sound detecting device and including means for receiving the transmitted signal and speaker means and/or visual display means for reproducing the detected sound and wherein the system incorporates a synthesiser and microprocessor control system to allow the selection of one, or a number, of a range of frequency values which is/are to be used to transmit the signal from the sound detecting device to the receiving device.
2. A noise monitoring system according to claim 1 wherein the signal is transmitted using one of a selectable range of FM low frequencies.
3. A noise monitoring system according to claim 1 wherein the microprocessor control system allows any or any combination of the control of power management of the power supply to the device, battery strength indication means and signal strength indication means either alone or in combination.
4. A noise monitoring system according to claim 1 wherein means are provided to sense the temperature in the vicinity of the sound detecting device.
5. A noise monitoring system according to claim 4 wherein a signal indicative of the sensed temperature is transmitted to the receiving device and a temperature value can be displayed.
6. A noise monitoring system according to claim 1 wherein a Liquid Crystal Display (LCD) is used to indicate functions and function values on both or either of the sound detecting device and/or receiving device.
7. A noise monitoring system according to claim 6 wherein any or any combination of battery power, signal strength, channel, temperature and/or a time clock can be set and displayed on the LCD.
8. A noise monitoring system comprising a sound detecting device including a signal transmitting means for emitting a signal indicative of the sound heard, a receiving device which can be positioned remote from the transmitting means for receiving the emitted signal and speaker means for relaying the reproduced noise to a listener and wherein the system incorporates a synthesiser and microprocessor control system and said signal is carried by one of a number of selectable frequencies on one of a number of selectable channels, said frequencies and/or channels operable with security code so that the transmitted signal can only be received and processed by the receiving device if it is set to operate with a matching security code, thereby reducing cross interference from other apparatus.
9. A noise monitoring system according to claim 8 wherein the microprocessor allows the setting of security codes for a plurality of frequency values on each crystal controlled channel.
10. A noise monitoring system according to any preceding claim wherein the microprocessor includes a setting to allow the user or manufacturer of the system to select and control the operating parameters of the system.
11. A noise monitoring system according to claim 10 wherein the microprocessor is adapted to select available frequency values for transmission of the signal from a range of values upon input of country information or a code which causes the system to select the available frequencies which can be used.
12. A noise monitoring system according to claim 10 wherein manual control means are provided to allow the manual selection of operating parameters.
13. A noise monitoring system according to any preceding claim wherein the range of frequency values held in the synthesiser for use are in the range of 26 to 868MHz.
14. A noise monitoring system according to claim 10 wherein the frequency values selected from the range are set during or immediately after manufacture of the system devices in relation to the country in which the same are to be used.
15. A noise monitoring system according to any preceding claim wherein the frequency settings for a designated country are set by the manufacturer of the device or the company responsible for onward sales, and the end user of the system is not able to select the country.
16. A noise monitoring system according to any preceding claim wherein codes, each of which relates to a specific country and available frequency values for that country, are held in a memory of the microprocessor.
17. A noise monitoring system according to any preceding claim wherein the sound detecting means comprises a microphone.
18. A noise monitoring monitor system for use in a premises comprising a sound detecting device including a microphone for detecting a sound in the vicinity of the device, digital signal transmitting means for transmitting a signal indicative of the sound in a digital format, a receiving device which can be positioned remote from the sound detecting device and including a means for receiving the digital transmitted signal and speaker means and/or visual display means for processing and reproducing the signal via the speaker means and/or visual means and wherein the system incorporates a synthesiser and microprocessor control system to allow the selection of one or a number of a range of frequency values stored in the system to be used to transmit the signal from the signal transmitter to the signal receiver.
19. A noise monitoring system comprising a sound detecting device including a sound detection means for detecting sound in the vicinity of the device, signal transmitting means for transmitting a signal indicative of the sound, a receiving device which can be positioned remote from the sound detecting device and including a means for receiving the transmitted signal and speaker means and/or visual display means for processing and reproducing the signal via the speaker means and/or visual means and wherein the transmitted signal is encoded into a digital format at the sound detecting device, transmitted and decoded at the receiving device by a microprocessor system.
20. A noise monitoring system as hereinbefore described with reference to the accompanying drawings.