AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION INNOVATION PATENT WIRELESS WATER CONSUMPTION MONITOR The following statement is a full description of this invention, including the best method of performing it known to me: 1 WIRELESS WATER CONSUMPTION MONITOR Water usage within Australia has become a critical issue in the past few years and awareness has grown within the community for better management and utilisation of water. Water authorities have prescribed water restrictions and daily limits for water consumption per person in order to sustain water supplies in drought conditions and to serve future needs of an ever growing population. Whilst these prescribed daily limits are well known within the community, water users do not have ready access to actual daily consumption figures unless the user has the vigilance to record water meter readings on a daily basis. This problem is well known and modern water meters are typically designed to facilitate some form of electronic totalisation and many systems have been developed to electronically gather and transmit information to water authorities for billing and regulation purposes. The focus of the invention described herein is to take advantage of the said electronic totalisation capability to provide direct visual feedback to the water consumer. Many common water meters have magnets fitted on the internal moving parts that allow electronic detection of the movement of the internal mechanism using a simple magnetic transducer. When connected to electronic circuitry, the transducer generates an electronic pulse each time an internal magnet passes by the transducer and the occurrence of each pulse represents a specific volume of water that has passed through the water meter. The disclosed invention typically includes a magnetic transducer and electronic totaliser and has the further capability of remotely displaying information in a format that allows the water consumer to directly compare daily consumption against prescribed or normative figures. It provides water users with detailed and timely information and statistics in relation to water consumption and comprises two physically separate portions that are interconnected using wireless information transmission. The first portion is a wireless sensor that is capable of monitoring the occurrence and volume of water flow through a commonly available domestic or commercial water meter. The second portion is a receiver unit with corresponding visual display that allows consumption and flow information, received from one or more wireless sensors, to be viewed in a convenient location, typically inside a building. A significant feature of the invention is the ability to display water consumption statistics on a per person basis, 2 thereby offering the user the convenience of a direct comparison of actual consumption on the same basis as limits prescribed by water authorities. In an embodiment of the invention, the wireless sensor is powered from a battery and an optional solar panel, and a low power radio transceiver is used to transmit water flow information by encoded radio signals to the receiver unit which contains a similar transceiver. The wireless sensor includes a magnetic transducer that can be located within, or on a common water meter. Typically the transducer will be a reed switch and the electronic signal will be a series of digital pulses whereby the occurrence of each pulse represents the passage of a known volume of water through the water meter. Alternately, and for ease of installation, the transducer may be a magnetic field sensor located on or near the body of the water meter to detect the movement of magnets within the water meter. In this case the electronic circuitry includes an amplifier and discriminator circuit to generate electronic pulses. A further alternative exists where the water meter has an in-built electronic interface with a pulse-output circuit that can be directly connected to the wireless sensor, without requirement for the sensing transducer. The volume of water represented by each pulse depends on the construction of the water meter and is usually able to be ascertained from manufacturer's data for each model of water meter. The volume of water per pulse is entered by the user and is stored within the receiver unit to allow the accumulated pulse total to be displayed and stored as litres or gallons. The wireless sensor includes integrated circuitry which, upon detection of each pulse, increments a numerical accumulator and measures the time between successive pulses to deduce rate of water flow. The accumulator total and flow rate is sent via wireless transmission to the receiver unit on a regular basis; the time between transmissions being a compromise between battery life and rate of information update within the receiver unit. The said wireless transmission may also include ancillary information such as unique identification code, battery health, installation details and checksum information. The inclusion of a unique identification code allows the receiver unit to identify the source of information and therefore allows data to be collected from one or more wireless sensors, known to the receiver unit and to ignore or treat differently information received from neighbouring systems or from wireless sensors not known by the receiver unit. The inclusion of checksum information provides a means for the 3 receiver unit to validate the information received and thereby reduce the chance of processing or displaying erroneous data. In a preferred embodiment the checksum information would be in the form of a 16 bit cyclic redundancy check code (CRC). Data maybe wirelessly acquired from the receiver unit, which itself would contain a unique identification code, or from wireless sensors, by an independent receiver, typically a hand-held or portable data collection device. In this case the independent receiver would accept data from every device and collate the information typically for use by water authorities and Government agencies. In a preferred embodiment both the wireless sensor and receiver unit include radio transceivers with the capability for bi-directional communications. Upon reception and decoding of information, the receiver unit sends an acknowledgement message back to the wireless sensor. Such messages indicate to the wireless sensor that information was properly received and that no further attempt to transmit is required. And in the event that the receiver unit does not receive a valid reply then the wireless sensor automatically retransmits the data, within a limited maximum number of attempts. The use of bi-directional radio communications also enables prolonged battery life by automatically adjusting the wireless transmit level is to achieve reliable error free communications using the minimum possible transmit power. Once accepted by a receiver unit, the information received from wireless sensors is used to calculate and display sensor information and derived statistics for individual wireless sensors and the data may be collated and combined so that overall consumption totals may be displayed and compared. By way of example, a plurality of wireless sensors and an associated receiver unit may be installed on a number of sub-mains water meters, such as those fitted on individual houses, with one wireless sensor fitted to the master mains water meter upstream of the sub-mains meters. The invention would allow display and comparison of individual sub-mains and of the master mains consumption statistics as well as the statistics for the combination of sub-mains meters versus the master meter. The receiver unit receives and decodes the accumulated totals and flow rate from one or more wireless sensors and computes further information derived from the sensor 4 information. It also has the capability of interpreting, processing, storing and displaying information derived from the sensor information. The methods of said processing include segmenting and totalizing water volumes and flow rate over specified time periods and computation of peak flow rate, minimum flow rate, water demand and other flow and consumption statistics which may be expressed as totals or on a per-person basis. This processing of information over specified time periods includes but is not limited to: total accumulated volume, current flow rate, peak flow rate, minimum flow rate, and total volume of water consumed for hourly, daily, monthly, quarterly and yearly weekly time periods, for individual or pre-defined combinations of wireless sensors. These time periods may be historical, allowing comparisons to be drawn between current and previous periods: for example consumption this quarter versus last quarter. Based on the time of day, the receiver unit optionally includes the capability of detect and display normal and abnormal consumption behaviour, for example, occurrence of consumption during the small hours of the night. The receiver unit provides visual and/or audible alarms including low battery alarm, battery charge status, communications error alarm and other alarms which may be based on any of the sensor information or derived information. Specific examples of alarms provided by the invention include leak detection, prolonged use detection, night usage and rate alarms. A leak detection alarm is activated when the minimum flow rate exceeds a pre-defined value for a pre-defined period of time. The prolonged use alarm functions similarly, only with different parameters for minimum flow and time period. A night use alarms is raised if a pre-defined minimum flow rate is detected during pre defined time periods. A flow rate alarm is activated when a maximum flow rate exceeds a pre-defined value. Said pre-defined values may be set by the user and stored within the receiver unit. In an embodiment, these warnings can be displayed on the LCD screen or monitor and may also be indicated by flashing LED indicators or illuminated buttons on the receiver unit. Similarly, the LED indicators or illuminated buttons may be used to indicate the status of consumption by flashing at a rate proportional to the water flow rate.
5 A further capability of time-based processing is the display of one or more sensor variables over a time period, in a similar fashion to a stop-watch. Starting the time based processing is achieved by pressing or clicking on a start button, which has the action of clearing the displayed values starting a timer, and allowing the values of said variables to update until such time as the user presses a stop button. The resultant display may show, for example, the total volume, flow rate, usage per person, or other statistics as mentioned herein, for the given time period for which the 'stopwatch' was operational. By cancelling the stop watch mode, the former functions and displays resume with totals updated as per the volumes consumed during the stopwatch mode. The values displayed in the stopwatch mode may be from a single sensor or from a combination of sensors. The receiver unit is typically located indoors for easy and frequent inspection and may be in the form of a portable device. The preferred embodiment of the receiver unit is a compact unit with internal low power radio transceiver and microprocessor and has illuminated control buttons, an LCD display and an optional computer interface. Alternately the receiver unit may be a computer peripheral, such as a "USB stick" whereby the information is displayed by a computer or computer device such as a personal digital assistant (PDA) or mobile phone. Further, the receiver unit may be a third-party computer device with integral wireless interface such as Bluetooth, Zigbee or wireless USB to communicate directly with wireless sensors having the same wireless communications protocol. In this case the device would run application software to allow communications with and data collation and display of information from the wireless sensors. In the case where the receiver is a compact unit, power may be supplied by a plug-pack and/or by internal batteries which in a preferred embodiment are rechargeable and are charged by the plug-pack. The use of internal batteries allows the receiver unit to be hand-held during flow tests and during use of the stopwatch mode to visualize data at a convenient location. When connected to an external computer system or computer device, the information processed by and stored within the receiver unit may be sent to the said computer or computer device for further storage, processing, consolidation and display. The computer or computer device may include application software with the ability to provide detailed visual displays of the information and to store the data for historical reference 6 and graphical historical display. It also may generate visual and audible alarms and is capable of retransmitting the information via a computer network or mobile phone network. The sensor and/or receiver unit may have the capability to store information in non volatile memory for the purpose of unique identification, serial number and user settings. User settings include the mode of operation, transmission interval minimum and maximum, and alarm settings, volume of water per pulse, sensor identification numbers and sensor data combinations, calendar and time of day. A plastic or plastic/metallic enclosure is used to house the sensor with a required degree of environmental protection from moisture, pests and dust ingress that would otherwise be detrimental to the electronics. A means is provided to replace the battery in the sensor and where required to access connectors, buttons, miniature switches and any other interfaces required to program, configure and test the sensor. An antenna or antenna connection is provided for the wireless transceiver and may be in the form of a wire dipole antenna or a compact loop antenna. The preferred embodiment of the enclosure is formed from a combination of flexible and hard plastic materials. The flexible plastic material, which may be Polyurethane or Thermoplastic Elastomer, is used to over-mould the electronics in a similar fashion to moulded cables and plugs. The body of moulded soft plastic, herein called 'over moulding' completely envelops the electronics and associated sensor, thus providing a complete barrier against moisture and water ingress. The antenna can be etched on the electronics printed circuit board to avoid an external wire antenna and to take advantage of the environmental protection provided by the over-moulding. The preferred embodiment uses a length of wire for antenna which extends through the over-moulding and is retained by a groove on the external surface the over-moulded enclosure. The wire remains internal to the enclosure whilst providing relatively high gain characteristics. Likewise the transducer may be directly fitted on, or attached to, the electronics circuit board so that it is incorporated within the over-moulding. Alternately where distance is required between the enclosure and the transducer, a connecting cable can extend from 7 the over-moulding to the magnetic transducer which may be encased within a separate over-moulding located at the end of the connecting cable. The battery may be included in the over-moulding, or in a preferred embodiment, can be external to the over-moulding and electrically connected to the circuit board by means of metallic posts mounted to the electronics assembly and that protrude through the soft plastic moulding. The battery posts then allow connection of a battery or battery pack located within a battery holder or preferentially within a removable cover. Light emitting diodes mounted on the circuit board are made visible by reducing the thickness of the translucent over-moulding plastic material near the diodes. The use of light emitting diodes provides visual indication that the unit is powered and is measuring and communicating properly. The over-moulding process may involve injection of molten plastic at considerable pressure and temperature to the possible detriment of the electronic components that may exist within the over-moulding. The nature of the over-moulding also prevents any future access to any parts of the electronics, such as connectors, unless they are incorporated in the over-moulding and pass through the moulding, as in the case of the above-mentioned battery posts. These problems are overcome by incorporating a hard plastic cover, typically made from ABS or polycarbonate, that snaps over the circuit board and provides a pressure seal during the over-moulding process, preventing the soft plastic from touching sensitive areas and components. The said cover may also provide an access port which protrudes through the over-moulding and may be sealed using a plug, cap or by a plastic cover. In a preferred embodiment the over-moulding also includes a sealing ring for retaining a corresponding hard plastic lid. The said lid, typically made from UV stable ABS or polycarbonate, acts as a sun shield and includes a battery holder for easy battery replacement and may incorporate tamper-proofing fasteners or a locking facility. An important operational aspect of the invention is to prolong the life of the battery supply and hence minimize required maintenance. Two schemes may be used to reduce power and are available for selection by the user. The first is where radio transmission occurs at a regular interval, for example once per minute. The second 8 scheme involves transmitting the information only when flow is detected. In either scheme the electronics is put into a state of minimum power consumption when measurements and data transmission are not occurring. The preferred scheme is a combination of the above, whereby information is transmitted upon detected flow and within limits of minimum and maximum time period between transmissions. The radio frequency (RF) transmit power may also be fixed or adjustable: the benefit of reducing power would be to prolong battery life at the expense of radio range. The invention is illustrated in the attached figures which are explained as follows. Figure one shows the wireless sensor 1 and the receiver unit 5 separated by a distance and interconnected by wireless transmission 4. The wireless sensor is mounted on a commonly available water meter 2 and is connected electrically to a pulse output circuit provided by the meter or by an associated transducer 3. The receiver unit is shown as a compact unit with integral LCD display 6 and keypad 7. Power to the receiver unit is from a plug-pack 8 or from internal batteries. An optional computer interface (not shown) allows data to be gathered and further stored, displayed and retransmitted by a computer device or computer network. Figure two shows a possible embodiment of the wireless sensor circuitry. A magnetic transducer 9 located on the water meter water detects the presence of moving magnets within the water meter and closes and opens electrical contact at a rate proportional to the water flow. The electrical contact is used to generate digital pulses via pulse generator circuitry 10 that provide digital pulses to microcontroller 11 that digitally accumulates said pulses and determines the present pulse rate based on a crystal based timer within the microcontroller. The microcontroller digitally transmits information using radio transceiver 12 to the receiver unit via antenna 13 which may be a wire antenna or a loop antenna integral within the sensor. The battery supply 14 typically consists of commonly available Alkaline or Lithium batteries. Alternately for water meters having an electronic pulse output, the transducer 9 is not required and is replaced by a direct connection to an output circuit provided by the water meter. Said electronic meters may include flow meters of various styles including electromagnetic flow meters.
9 Figure three shows a possible embodiment of the receiver unit. Radio frequency (RF) signals from one or more wireless sensors are received by the antenna 15 and a radio transceiver 16 which demodulates the radio signals into a serial digital bit-stream. The serial bit stream is decoded by a CPU 17 which interprets and processes the data. The CPU includes a Real Time Clock (RTC), memory and optional communications interfaces such as USB or a network (not shown). The data is processed by the CPU 17 and used to calculate direct information, such as battery voltage, derived information, such as water volume and consumption statistics, such as the average daily volume of water consumed per person. The said information is displayed on the LCD display or screen 18 and is stored by the CPU in memory 17 to provide historical data and further statistical computations. Optionally the information may be sent to another computer device or network. A keypad is used to select windows or pages of information and to configure the receiver unit with user settings and add new wireless sensors. A plug pack and optional rechargeable batteries 19 provide power to the circuitry. The real time-clock function in 17 allows data to be segmented and displayed for specific time periods during the day or for specified days of week. The information displayed by 18 may comprise graphical displays, numerical data and text. Light emitting diodes and/or output circuits may also be used for status indication (for example low battery or communications error), and for indication of flow rate or abnormal consumption. Alternately the receiver unit depicted in Figure 3 may be in the form of a portable collection device for the purpose of routinely gathering consumption information from a number of wireless sensors or fixed receiver units for purposes of billing or supervisory monitoring. Outputs from the receiver unit may include serial communications such as USB or Firewire. Or there may be a second wireless connection, such as Bluetooth, Zigbee or wireless USB to allow information transfer from the receiver unit to another system, such as a computer or communications networking device. Figure 4 shows the receiver circuitry in the form of a USB Stick. Radio signals from one or more wireless sensors are received by antenna 20 and transceiver 21. An optional microcontroller is shown in 22 which performs the sensor communications functions and information processing, or optionally may be performed by the host computer into which 10 the receiver unit is plugged. Power 24 and communications with the host computer are provided by a USB connector 25 and USB interface circuit 23 which includes the USB device protocol stack and associated USB protocol information including Vendor ID and Peripheral ID codes. Figure 5 illustrates the general arrangement of an embodiment of the enclosure and associated components and is shown as a section view. A printed circuit assembly 34 contains electronic components 35 mounted on a fibreglass circuit board that optionally includes an etched antenna (not shown). Soft plastic material (such as Polyurethane) is moulded over the printed circuit assembly to provide a solid form 30, with complete water and dust protection. A hard plastic cover 32 is located on the printed circuit assembly and provides an air barrier between the soft plastic over-moulding 30 and the electronic components 35. Metallic posts 31, are attached to the printed circuit assembly and are moulded within, and protrude through, the soft plastic body to allow contact with batteries, 27 retained within a hard plastic lid 26 which acts as a heat and sun shield. The hard plastic lid 26, shown removed from the over-moulding, locates within a recess (not shown) and seals against a rim moulded within the soft plastic body 30. Where the antenna is not etched on the printed circuit assembly, a wire antenna 29 is attached to the printed circuit assembly 34 and fed through a passage hole within cover 32 so that the antenna is substantially located outside the over-moulding 30. The soft plastic over-moulding includes a grove (not shown) to retain the wire antenna. It also includes recessed areas with holes 33, to facilitate mounting on a surface or bracket. The mounting holes and associated fasteners, and external antenna are covered when lid, 26, is fitted. The soft plastic over-moulding and hard plastic cover are thinned down in areas to allow light to pass from light emitting diodes, 36 to be visible from the outside of the enclosure. The transducer can be located at a distance from the printed circuit assembly by moulding a connecting cable 28, within the soft plastic over moulding 30, and within a separate moulding, 37, that contains the transducer 38. Figure 6 shows a further possible embodiment of both the wireless sensor and receiver units, as depicted as a general arrangement with cutaway views. The wireless sensor is made physically compact by integrating the magnetic transducer 44 which fits directly within the body of a water meter 39 and incorporates a loop antenna 40 on the printed circuit board 43. The plastic enclosure 42 which may be constructed from materials