MonitorsThis invention concerns monitors, and relates in particular to devices allowing the monitoring at a distance of a baby in its room.
It is common for babies beyond a certain age - six or so weeks, for example - and infants to have their own room (the nursery) in which they sleep and play. In many households it may be possible for the child's mother or father, or whoever is minding the child, to be near enough to hear any noises, particularly cries, that the child may make, or so frequently to visit the child that no more than a few minutes will pass between the child beginning to cry and the Minder coming to see it.
In other households, though, this is more difficult, or is somewhat inconvenient, and so it is common for there to be employed some sort of baby monitoring device - a sound transceiving apparatus, with a microphone/ transmitter in the child's room coupled to a loudspeaker/receiver carried by or located adjacent theMinder - so that any noises the child makes are instantly transmitted to and received by the Minder, who can then go and investigate what, if anything, is wrong with the child.The transmitter and receiver can be linked by wire, or other physical connection, but it is most usual these days for them to be coupled either inductively or electromagnetically - in the latter case, by radio (usually Very High Frequency [VHF] radio of only a short range) - both to permit the receiver to be placed anywhere suitable in the building without trailing unsightly wires behind it and also to allow the Minder to move about in the building carrying the receiver free of the encumbrance of'those same wires.
Paediatricians nowadays consider that an important factor in a very young child's life is the ambient temperature, for the bodies of small children - and especially new babies - have not yet achieved the good, automatic temperature control possessed by adults. It is desirable that a baby be kept warm, but not too warm - that when asleep it be protected by blankets and other bed clothes if the room's temperature is low, but that it should not be covered by so many layers that it become too hot if the room temperature should rise. It is therefore necessary for the ambient temperature of the child's room to be taken into account, and for the appropriate changes to be made - either to the heating or to the baby's coverings - if the temperature rise or fall beyond suitable limits.The invention seeks to render this task easier by providing the child's Minder with up-to-date information about the room temperature.
More specifically, it proposes that at regular and frequent intervals the Minder should be advised of the room temperature by apparatus forming an extension, as it were, of the normal monitoring equipment, this being one wherein associated with the transmitter is a temperature sensor that provides a temperatureindicating output which, much like any output from the monitor's microphone, is transmitted to the receiver and there displayed by appropriate display means for theMinder to see and act upon.
In one aspect, therefore, the invention provides child-monitoring apparatus enabling the Minder of a child to hear what noises are made in the child's room, the apparatus being of the type having a microphone and transmitter (to be placed in the child's room) and, operationally linked thereto, a receiver and speaker to be positioned adjacent the Minder's location, which apparatus also includes associated with the transmitter a temperature sensor that provides a temperatureindicating output which is transmitted to and displayed upon display means associated with the receiver.
The invention provides child-monitoring apparatus of the type having a microphone and transmitter (as a single module) operationally linked to a receiver and speaker (again, as a single module: this may possibly be portable, and carried/worn by the Minder). These components may be of any suitable variety, and may be coupled in any appropriate way (though especially by a short-range VHF radio link, as noted above).The apparatus may also include other features appropriate to a child monitoring device, such as: a sleep mode (when either or both the transmitter and receiver are powered down, and do not communicate one with the other); a diagnostic testing ability (for checking that the various alarms etc are actually working); an out-ofrange warning (for when the minder moves too far from the transmitter); a visible warning of the child crying (typically a row of Light Emitting Diodes [LEDs], on the receiver module, more of which light as the crying increases in amplitude); and, if battery-powered, a "battery low" warning. An instance of a typical such transceiver apparatus presently available on the market is that made by Playskool and sold under the nameROAMER III.
The apparatus of the invention includes, associated with the transmitter, a temperature sensor that provides a temperature-indicating output. The sensor may be of any suitable type - for example, it may be a thermistor type - and its output (which is transmitted to and displayed upon display means associated with the receiver) is most preferably shown, advantageously by a small LCD screen, on the transmitter module, so that when in the room the Minder can check the room's temperature simply by referring to the module's display.
It is desirable that the temperature display be switchable between Centigrade/Celsius ("C) andFahrenheit ("F).
Although such a child-monitoring apparatus will be used primarily indoors, with the child in its room, it is possible that a similar set-up might be required for a child outdoors in its pram. A temperature sensor suited for indoor use might not be appropriate for outdoor use, so it might be desirable for the apparatus to include two sensors, one for indoors and one for outdoors, suitably switched.
The temperature sensor's output is transmitted to the receiver, and this can be accomplished in any suitable way. When using a VHF radio link, however, it is very much preferred to provide a sub-carrier modulated by the temperature data.
The transmission of the temperature data can be continuous - that is to say, non-stop - but it will normally be necessary only to send the data at regular but relatively infrequent intervals. For example, it might be transmitted no more often that every five minutes. Another possibility, though, is to compare the present temperature with whatever it was a short time - say, 30 seconds - ago, and to transmit the current information if, and only if, it is actually different from what it was then. A third possibility is for the transmission to be voice activated - that is, for a cry or other sound from the child to trigger the transmission of the present temperature data. And, of course, all three of these could be employed.
Desirably the apparatus of the invention will be able to record - most conveniently in the transmitting module - the maximum and minimum temperature it detects.
In the invention's apparatus the transmitted temperature information is displayed upon display means associated with the receiver. Like the display on the transmitter module, the receiver module display is conveniently an LCD display, and is most desirably switchable between "C and CF.
It may be advantageous for the Minder to be able to set the transceiver apparatus of the invention to provide not merely a display of the temperature in the child's room but in addition some sort of visible or audible warning if the temperature goes up (or down) beyond certain predetermined limits. In such a case, then, the apparatus - and preferably the receiver section thereof - conveniently includes both programming means and warning means that together first permit theMinder to set upper and lower limits, and then provide the relevant warning - a buzzer, say, or a flashing light - if the actual room temperature goes up or down beyond the pertinent limit.
An embodiment of the invention is now described, though by way of illustration only, with reference to the accompanying Drawings in which: Figure 1 shows a block schematic diagram of atransmitting module - the baby unit - ofthe baby-monitoring apparatus of theinvention; andFigure 2 shows a block schematic diagram of amatching receiving module - the motherunit - of the baby-monitoring apparatusof the invention.
In the transmitting module the components are as follows:- MCU. This is a single chip microprocessor which controls all the input and output signals, and also drives the LCD display and the alarm signal outputs.
INSIDE/OUTSIDE SENSOR. Each of these is a temperature sensor that uses a thermistor for measurement.
MIC AMP. This is an amplifier that effects voice amplification to an appropriate level with gain control.
VOICE ACTIVATE. This is to hold and compare the microphone signal, and output a control signal to trigger tone generator I and power switch.
TONE GENERATOR I. This generates a 90Hz tone signal when triggered by the voice activate control.
TONE GENERATOR II. This generates a 135Hz tone signal, and is controlled by the MCU data signal.
CRYSTAL OSC & MODULATION. The signal frequency is modulated with the crystal oscillating frequency.
FREQ. MULTIPLIER. This multiplies the fundamental frequency to the third overtone carrier frequency.
R.F. AMP. This amplifies the carrier frequency, and outputs it to the antenna.
POWER SWITCH. This is a transistor power switch which controls the R.F. transmission.
In the receiving module the components are as follows:MCU. This is a single chip microprocessor which can receive all input data and output it to an LCD display and buzzer alarm.
R.F. AMP. This receives the radio frequency from the antenna, and performs amplification.
MIXER. This mixes the local oscillations with the carrier frequency.
I.F. AMP. This uses a narrow band I.F. IC for amplification, and outputs the recovered audio signal.
TONE DETECTOR I. This uses a two-state tone filter to detect out the tone signal and convert it to a DC voltage.
TONE DETECTOR II. This uses a two-state tone filter to detect out the data tone signal and convert it to DC levels.
COMPARATOR. This compares the input signal voltage with the preset level, and performs output control.
POWER SWITCH. This is a transistor switch which controls the on/off state of the audio amplifier.
AUDIO AMP. This is to amplify the audio signal, and provides volume control, and outputs it to the speaker.
BAR GRAPH. This amplifies the audio signal and drives the sound level LEDs.
The operation of the apparatus is as follows:Transmitter (baby unit) 1) This uses a 4-bit OKI MSM64152 MCU for temperaturemeasurement and recording, timing and data outputcontrol. It can directly drive the LCD displaywith 4-8 digits with 4 mux multiplexing. Thetemperature recording range is from -20 C to +50"C, and the resolution is 0.1"C (or "F). The datasent-out rate is 10 bits/sec, data refresh rate per15 to 20 seconds. The alarm signal beep tone is0.2 sec on, 2 sec off.
2) All data can be transmitted to the receiver (themother unit) through a radio link. In thetransmitter (the baby unit) a 135Hz tone signal isused with tone switching on and off to simulate thetiming. Data-enable pin from the MCU controls theperiod for data transmission. The voice signal isreceived through the microphone, and afteramplification is sent for modulation, and passed tothe voice-activate circuit. Another 90Hz tonesignal is used for audio signal transmission. Allthe signals are modulated at the variablecapacitance diode (vcd) with crystal oscillation.
After being multiplied to the carrier frequency thesignals are send to R.F. amplification, and then goto the antenna.
Receiver (mother unit) 1) This uses a 4-bit OKI MSM64152 MCU for dataprocessing, driving the LCD, and displaying thetemperature status, and the out-of-range alarmsignal.
2) In the receiver (the mother unit) the voice- anddata-modulated carrier frequency is received fromthe antenna, and sent to an R.F. amplifier foramplification. It is then mixed with the crystalfrequency, and the audio component extracted andamplified.
Another part of recovered audio signal is sent tothe tone detector stage; at tone detector I thetone signal is filtered out at sinusoidal form andsent to the comparator, and after comparison thecomparator outputs a control voltage to switch onthe power supply to the audio amplifier, whereuponaudio sound can be heard from the speaker. At tonedetector II, the on/off data tone signal isrecovered in DC level and sent directly to thecomparator. The data chain is then sent to theMCU's input port for data processing, and fordisplaying the status.