GB2396043A

GB2396043A - Baby alarm with tilt sensor

Info

Publication number: GB2396043A
Application number: GB0228309A
Authority: GB
Inventors: John Phizackerley
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-12-04
Filing date: 2002-12-04
Publication date: 2004-06-09
Also published as: GB0228309D0

Abstract

A baby monitoring system comprises an attitude sensor 1 attachable to a baby's clothing or skin. The sensor 1 contains a tilt switch 5, control circuit 6, transmitter 7, antenna 8 and is powered by battery 9. The sensor communicates with receiver (2) which has an audio or visual alarm. The alarm is triggered if the sensor detects that the baby has adopted a position associated with increased risk of cot death (SIDS). The sensor may also include means for detecting vital signs such as a heart rate and temperature. Other embodiments show that the sensor may be incorporated into a conventional baby listening device with a monitoring station (20) which has a microphone (23) and a base station (30) which has a loudspeaker (33).

Description

BABY ALARM

The present invention relates to monitoring equipment, and is particularly concerned with an apparatus for 5 monitoring the sleeping attitude of an infant.

The phenomenon of Sudden Infant Death Syndrome (SIDS) is of great concern to parents of young babies. Medical research has established an apparent link with the 10 sleeping attitude of a baby and its susceptibility to SIDS, and the present invention seeks to provide a monitoring device which can give a warning signal when a baby moves into an attitude which is considered to expose the infant to a greater risk of SIDS.

There currently exist baby monitoring devices which provide a microphone for listening for a baby's cry, and more sophisticated pressure-sensing devices which provide the possibility of monitoring a baby's heartbeat when in 20 a cot. However, neither of these devices provides any indication as to the sleeping attitude of the baby and thus cannot alert the parent to a movement of the baby which increases its risk of SIDS.

25 The present invention seeks to address the deficiencies of the prior art by providing a baby monitoring device

which gives an indication to the parent when the baby

moves into an attitude of increased danger.

According to a first aspect of the invention there is provided a baby monitoring system comprising a sender 5 unit, attachable to a baby or its clothing, and a receiver unit. The sender unit includes an attitude sensor and a transmitter, and sends an output signal when the sender unit is in a predetermined orientation relative to the vertical. The receiver unit comprises 10 a receiver for receiving the signal from the sender unit, and an alarm device for emitting a warning on the basis of the received signal.

In use, the sender unit is attached to the baby or to its 15 clothing in such a position that the sender will emit a signal if the baby adapts an attitude perceived to increase its risk of SIDS. The signal will be received by the receiver unit and the alarm will be given as an audible or visual alarm by the alarm device.

20 Alternatively, the sender may be arranged to emit a signal when the baby is in a "safe" attitude, and cease the emission when the baby adopts an attitude of increased risk. In this arrangement an alarm is given by the receiver when no signal is received.

A second aspect of the invention provides a monitoring system comprising the sender unit, a receiver unit, and

a monitoring unit. In this aspect, the receiver unit further comprises a microphone and is operable to transmit first signals in response to the signal received from the sender unit and second signals representing 5 sounds detected by the microphone. The monitoring unit includes a receiver to receive signals from the receiver unit, and output means operable in response to the second signals to reproduce sounds detected by the microphone of the receiver unit, as well as to provide an alarm in 10 response to the presence or absence of first signals from the receiver unit.

In use, the second aspect provides for monitoring both the sleeping attitude of the baby, by detecting signals 15 from the sender unit relating to the baby's position, and also for monitoring any sound produced by the baby. In this aspect, the sender unit is attached to the baby or its clothing as before, and the receiver unit is placed sufficiently close to the baby so that the microphone can 20 detect its cries. The monitoring unit is placed so that the parent can hear the babies cries reproduced by the monitoring unit, and can also hear or see an alarm emitted by the monitoring unit in response to signals from the receiver unit.

A third aspect of the invention provides for a method of monitoring a baby's attitude by attaching an attitude

sensor to the baby or to its clothing in a predetermined orientation relative to the baby, transmitting a signal from the attitude sensor when the attitude sensor is placed in a predetermined orientation relative to the 5 vertical, detecting the signal and selectively producing an alarm on the basis of the detected signal.

A fourth aspect of the invention provides a sensing device for a baby monitoring system, the sensing device 10 comprising a casing attachable to a baby and containing an attitude sensor and a transmitter, the arrangement being such that the transmitter sends a first signal when the casing is in a first orientation relative to the vertical and a second signal when the casing is rotated 15 by a predetermined amount away from said first orientation. The attitude sensor may be a conductive liquidcontaining enclosure such as a mercury switch, or a moving pendulum 20 or piezoelectric beam sensor.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 shows a baby in a supine position, with an alarm sensor button attached to the baby's clothing.

Figure 2 is a perspective view of the alarm sensor button to an enlarged scale, partially cut away to show internal detail; 5 Figure 3 is a schematic diagram of a first base station for use with the sensor button; Figures 4a and 4b illustrate the sensor button in two alternative orientations, showing the operation of the 10 attitude sensor; Figure 5 illustrates schematically a baby monitoring system comprising a sensor button, a monitoring station and a base station; Figure 6 is a schematic cross-sectional view of an alternative embodiment of the sensor button; and Figures 7a and 7b are partial sectional views of a 20 further sensor button showing an alternative attitude sensor. Referring now to the drawings, a first embodiment of the baby monitoring system comprises a sensor button 1, 25 illustrated in Figures 2 and 4, and a monitoring station 2, shown in Figure 3.

Referring now to Figures 2 and 4, the sensor button 1 comprises a substantially disk-shaped casing 3 formed on its underside with an attachment device 4. The attachment device 4 may be a burr-type fastener having 5 a plurality of hooks for attachment to the baby's clothing. The baby's clothing may have fixed thereto a complementary burr-type fastener at an appropriate location, or may be provided with a pocket to contain the sensor button.

Alternatively, the attachment device 4 may be an adhesive pad for fixing to the baby's clothing or skin. The adhesive will be selected from suitable medical adhesives which do not cause adverse skin reactions, the exact 15 nature of the adhesives being well known to those skilled in the art.

As a further alternative, the sensor button may be fixed inside the baby's clothing, so as to place the button in 20 contact with the babys body. In a yet further alternative, the casing of the sensor button may be provided with attachment points for a strap for securing the button to the baby or to a limb of the baby.

25 The casing 3 of the sensor button 1 is preferably waterproof, and the circuit components of the control circuit and the transmitter are preferably chosen so as

to be able to withstand immersion in hot water, so that the sensor button is not made unserviceable by accidentally washing the button with the baby's clothing.

5 Within the casing 3, the sensor button comprises an attitude sensing element 5, a control circuit 6, and a transmitter circuit 7 with an antenna 8. The control circuit 6 and transmitter circuit 7 are supplied with power by a battery 9.

The attitude sensing element 5 in the embodiment shown in Figures 2 and 4 is a mercury-filled tilt switch. When the sensor button 1 is in the attitude shown in Figures 2 and 4a, the mercury 10 within the tilt switch is spaced 15 from the electrical contacts 11, and no electrical contact is made. As an alternative to mercury, a non toxic conductive liquid such as water is usable.

When the sensor button is placed in the inverted position 20 shown in Figure 4b, the mercury or other liquid 10 within the tilt switch immerses the electrical contacts 11 and completes a circuit between them.

The control circuit 6 is arranged to detect the presence 25 of absence of electrical continuity across the contacts 11 of the tilt switch, and when continuity is detected, the control circuit 6 provides an output to the

transmitter circuit 7 which then transmits an alarm signal via the antenna 8. When the sensor button is in the orientation shown in Figure 4a, the absence of electrical continuity between the contacts 22 of the tilt 5 switch is detected by the control circuit 6, which does not provide any output to the transmitter circuit 7.

The sensor button 1 is fixed to the baby's clothing or to the baby in such a way that when the baby is in the 10 supine position shown in Figure 1, no output is generated from the sensor button 1. Should the baby turn over from the supine position shown in Figure 1 to a prone (face down) position, the sensor button will be re-oriented to the position shown in Figure 4b, and an alarm signal will 15 be broadcast via the antenna 8.

The base station 2 is placed within transmission range from the sensor button 1, and comprises a receiving antenna 12 connected to a receiver and control circuit 20 13. A battery 14 provides power for the receiving and control circuit 13, and a loudspeaker 15 is connected to the receiving and control circuit 13.

The receiving and control circuit 13 is arranged so that 25 when the alarm signal transmitted from the sensor button is received at the receiving antenna 12 the receiving and control circuit 13 causes the loudspeaker 15 to emit an

audible alarm. By placing the base station 2 within earshot of the baby's parent or carer, the parent can be alerted to a movement of the baby which increases its risk of SIDS and can then attend to the baby and replace 5 the baby in a less dangerous sleeping attitude.

The tilt switch 10 may alternatively be arranged to make contact when the baby is in a "safe" position, and break the circuit if the baby moves to an attitude of high 10 risk. The receiving and control circuit will be arranged to give an alarm signal when no signal from the sensor button 1 is received. The provision of an output from the sensor button in the "safes' condition will alert the user to a failed unit by setting off the alarm when the 15 baby is not at increased risk.

An alternative embodiment of the invention is shown in Figure 5, in which the attitude detection facility of the sensor button 1 is provided in conjunction with a 20 conventional baby listening alarm. In the embodiment shown in Figure 5, the monitoring system comprises a sensor button 1, a monitoring station 20 and a base station 30. In use, the monitoring station 20 will be placed in the same room as the baby, and the base station 25 30 will be placed with the babys parent or carer.

The sensor button 1 comprises the same elements as the

sensor button 1 previously described, i.e. an attitude sensing element 5, a control circuit 6, a transmitter circuit 7, an antenna 8 and a battery 9. The sensor button 1 is attached to the baby or to the baby's 5 clothing as previously described.

The monitoring station 20 comprises a control circuit 21 which can receive control inputs from a receiving circuit 22 having an antenna 22a, and can also receive an input 10 from a microphone 23. In use, the monitoring station 20 is placed sufficiently close to the baby that the microphone 23 can detect sounds such as crying made by the baby. The control circuit 21 provides output signals to a transmitter circuit 24 so that signals may be 15 emitted from an antenna 25. In an alternative embodiment (not illustrated) the transmitter circuit 24 and the receiving circuit 22 may be combined into a single tranceiver circuit, having a single antenna in place of the transmitting and receiving antennas 25 and 22a.

A battery 26 provides power for the control circuit 21 and the transmitting and receiving circuits 24 and 22.

The battery 26 may be replaced by an alternative power source such as a mains-powered transformer/rectifier.

The third element in the monitoring system is a base station 30 which comprises a control circuit 31, a

receiving circuit 32, a loudspeaker 33 and a power supply 34. The power supply 34 may be a battery pack, or it may be a mains-operated transformer/rectifier as shown in Figure 5. The power supply 34 is connected to the 5 domestic mains supply by a power cord 35 and plug 36.

In operation, the base station 30 receives signals from the monitoring station 20 via a receiving antenna 37 connected to the receiver circuit 32. The control circuit 31 processes the received signals and provides 10 outputs to the loudspeaker 33.

In a first mode of operation of the monitoring system, the microphone 23 of the monitoring station 20 is active and any sound made by the baby is detected. The 15 microphone 23 provides a signal to the control circuit 21 of the monitoring station 20, which then provides an output to the transmitter circuit 24. A signal is transmitted from the monitoring station 20 to the base station 30, and the control circuit 31 of the base 20 station provides an output to the loudspeaker 33 so that the sound made by the baby is reproduced at the base station 30 and can be heard by the parent or carer.

While the baby is in a supine position, the sensor button 25 1 provides a first output signal. Should the baby assume a prone position as shown in Figure 5, the sensor button 1 reacts to this change of attitude by transmitting a

second, different output signal. The second output signal is detected at the receiving antenna 22a of the monitoring station 20, and the receiving circuit 22 provides an input to the control circuit 21 of the 5 monitoring station. The monitoring station then transmits an alarm signal via the transmitter circuit 24 to the receiver circuit 32 of the base station. This alarm signal is received by the control circuit 31 of the base station, which then transmits an alarm signal to the 10 loudspeaker 33. An audible alarm is then given at the base station alerting the parent or carer to the change in sleeping attitude of the baby. The carer may then attend the baby and replace the baby in the preferred sleeping position.

In the above-described embodiments, the sensor button 1 is shown attached to the front of the baby's clothing.

It is to be understood that the attachment device 4 of the sensor button 1 may be provided on the opposite face 20 of the casing 3 of the sensor button 1, and the sensor button may then be attached to the baby's back. This will reduce the risk of the baby detaching the button from its clothing, since the button will then be substantially out of reach and transmissions from the 25 sensor button will not be masked by the baby lying on top of the button. Although not illustrated in the embodiments, the sensor button may include an on/off

switch to deactivate the sensor button when not in use, to avoid battery drain.

An alternative embodiment of the sensor button is 5 illustrated in schematic cross-sectional view in Figure 6. In this embodiment, the attitude sensing device 5 of the sensor button 1 is a rod 16 of piezoelectric material which is fixed at one end to the interior of the casing to extend in a cantilever fashion within the casing. A 10 weight 17 is attached to the free end of the rod 16, and applies a bending moment to the rod in a first direction when the sensor button is in the attitude shown in Figure 6, and in a reverse direction when the sensor button is inverted. The piezoelectric rod 16 generates a voltage 15 in response to the applied bending moment, and this voltage is applied to the control circuit 6. The change in the applied voltage which results when the sensor button is inverted is detected by the control circuit 6 and the control circuit provides an output to the 20 transmitter 7 when the sensor button is inverted.

In addition to the attitude sensing device 5 in the sensor button of Figure 6, there is also provided a microphone 18. This embodiment of the sensor button is 25 principally intended to be attached directly to the baby's skin by means of an adhesive pad 4. An opening 19 is formed in the adhesive pad to correspond with the

position of the microphone 18. The purpose of the microphone 18 is to listen for the babys heartbeat, and provide to the control circuit 6 an output corresponding to the baby's heartbeat. The control circuit 6 may then 5 process this signal and transmit, via the transmitter circuit 7, a signal to the monitoring station indicating the baby's heart rate. The control circuit 6 of the sensor button 1, or the control circuit 21 of the monitoring station 20 may process the signal to give an 10 alarm signal when the baby's heart rate is outside a predetermined range.

The monitoring system may be arranged so that the loudspeaker 33 of the base station 30 may provide an 15 audible output of the heart beat detected by the microphone 18. Alternatively, the base station 30 may be equipped with a visual indicator either to display a numerical representation of the baby's instantaneous heart beat, or to flash an indicator lamp in synchronism 20 with the baby's heart beat.

Figures 7a and 7b illustrate a further alternative embodiment of the attitude sensing element 5 of the sensor button 1. In Figure 7 there is shown a partial 25 sectional view of the sensor button 1. A swinging arm 40 is mounted to the interior of the casing 3 of the sensor button, the swinging arm 40 having a heel 41 which

can swing into engagement with a pair of electrical contacts 42, 43. The electrical contacts are held apart by resilient mountings 44. In the position shown in Figure 7a, the swinging arm 40 rests against the interior 5 of the casing 3 and the heel 41 is spaced from the electrical contacts 42 and 43. When the sensor button is inverted, the swinging arm 40 adopts the position shown in Figure 7b and the heel 41 of the swinging arm urges electrical contacts 42 and 43 togther completing 10 a circuit. The electrical contacts 42 and 43 are connected to the control circuit 6, and completion of the circuit through the contacts 42 and 43 causes the control circuit 6 to send an alarm signal to the transmitter circuit 7 as previously described. When the sensor 15 button is replaced in the position shown in Figure 7a, the swinging arm 40 returns under gravity to its original position, the heel 41 is spaced from the contacts 42 and 43 which are then separated by their respective resilient mountings 44.

While in the above embodiments the transmission of signals between the sensor button 1 and the base station 2 or the monitoring station 20 is preferably by means of low-intensity radio waves, the transmission may 25 alternatively be by high-frequency sound waves or by infra-red light. Similarly, transmission of signals between the monitoring station 20 and the base station

30 may be by radio signals, or if the monitoring station 20 and the base station 30 are mains-powered then data transmission may be made through the mains wiring.

5 While three different types of attitude sensing element have been described in the specification, it will be

understood that the sensor button may include any switching element which can give a differential output depending on the attitude of the sensor button.

In addition to, or as an alternative to, the microphone 18 for detecting the baby's heart rate, the sensor button 1 may be provided with a pair of external electrodes to be placed in contact with the skin of the baby. By 15 monitoring the voltage produced by the baby between the two electrodes, the baby's heart rate may be monitored or other vital signs detected. For example, the baby's body temperature may be measured and an indication of temperature transmitted to the monitoring and base 20 stations. As an alternative to the adhesive pad 4, the sensor button 1 may be attached to the inside of the baby's clothing by burr-type fasteners, adhesive, press studs or the like, and may be held in contact with the baby's skin by the fit of the clothing. The sensor 25 button may be held in a pocket sewn into the baby's clothing.

The control circuitry 6 of the sensor button 1 may include a memory circuit for storing identification data to be attached to transmissions from the transmitter circuit 7, so that a single monitoring station 2 or 20 5 may be used in conjunction with a plurality of sensor buttons 1 each having a different identification signal.

The control circuit 13 or 21 of the base station 2 or monitoring station 20 may include circuitry to identify the particular sensor button 1 which is giving an alarm 10 signal, and the base station 2 or monitoring station 20, or the base station 30 may include a display to indicate which of a plurality of sensor buttons 1 is showing an alarm signal. Such an embodiment may be of use in, for example, a nursery or maternity ward where a number of 15 infants may require simultaneous monitoring.

In the described embodiments, the attitude sensing element 5 is required only to sense a 180 inversion of the baby's position. It will be understood that if a 20 more sensitive sensing element is used, it will be possible to detect the current attitude of the baby in real time and transmit this information to the monitoring and base stations, for display on an appropriate display screen. An appropriate additional alarm, either visual 25 or audible, may be given when the baby adopts a position perceived to be at high risk. The control circuits may include time-delay provisions so that an alarm is only

sounded once the baby has adopted a high-risk attitude for a predetermined period of time. This will avoid alarm signals being given as the baby naturally moves through a high risk position, for example if the baby 5 rolls completely over without dwelling in the high-risk position for any appreciable time. The sensor button may also include a further attitude sensing device which detects the baby's adopting an erect attitude, such as if the baby should stand up in its cot. Such a 10 capability may also be useful, for example in a maternity ward for newborn infants, for detecting when a child is picked up out of its cot.

Claims

Claims:

1. A baby monitoring system comprising, a sender and a receiver unit, the sender comprising: 5 a housing attachable to an infant; an attitude sensing element mounted in the housing for providing a first output when the housing is in a first attitude relative to the vertical and a second output when the housing is rotated from the first 10 attitude by a predetermined amount; and transmitter means within the housing for transmitting a signal in dependence on the output of the attitude sensing element; and the receiver unit comprising a receiver, a 15 control circuit and an alarm device, wherein the receiver provides an output to the control circuit on the basis of the signal received from the transmitter, and the control circuit controls the alarm device to emit an alarm in dependence on the output from the receiver.

2. A baby monitoring system according to claim 1, wherein the housing is adapted to be attachable to clothing. 25

3. A baby monitoring system according to claim 1,

wherein the housing is provided with a Laying surface attachable to the skin by an adhesive.

4. A system according to any preceding claim wherein 5 the alarm is an audible or visible alarm signal.

5. A system according to any of claims 1 to 3, wherein the receiver unit further comprises a microphone for detecting audible sound and the alarm device is a second 10 transmitter, the system further including a monitoring unit comprising a second receiver, a control circuit and a second alarm device; and wherein the receiver unit is operable to transmit first signals representing the sounds detected 15 by the microphone, and the monitoring unit is operable to receive the first signals from the receiver unit and provide an audible output representing the detected sounds; and the receiver unit is operable to transmit second 20 signals dependent on the output of the transmitter means of the sender, and the second alarm device of the monitoring unit is operable to emit an audible or visible alarm on the basis of the second signals received at the monitoring unit.

6. A system according to any preceding claim, wherein the sender is provided with means to detect vital signs and to transmit signals representative of the detected vital signs to the receiver circuit.

7. A system according to claim 6, wherein the vital signs are heart rate and/or temperature.

8. A system according to claim 6 or claim 7, wherein 10 the receiver unit comprises a display device for displaying data relating to vital signs.

9. A system according to claim 6 or claim 7, as dependent on claim 5, wherein the monitoring unit 15 comprises a display device for displaying data relating to vital signs.

10. A sender button for a monitoring system according to claim 1, comprising: 20 a housing attachable to an infant; an attitude sensing element mounted in the housing for providing a first output when the housing is in a first attitude relative to the vertical and a second output when the housing is rotated from the first 25 attitude by a predetermined amount; and

transmitter means within the housing for transmitting a signal in dependence on the output of the attitude sensing element.

5

11. A sender according to claim 10, further including means for detecting vital signs.

12. A sender according to claim 11, wherein the means for detecting vital signs is a microphone.

13. A sender according to claim 11, wherein the means for detecting vital signs is a temperature sensor.

14. A baby monitoring system substantially as herein 15 described with reference to Figures 2 to 4, Figure 5, Figure 6 or Figure 7 of the accompanying drawings.

15. A sender unit for a baby monitoring system substantially as herein described with reference to 20 Figure 2, Figures 4A and 4B, Figure 6 or Figures 7a and 7b of the accompanying drawings.