GB2473237A - Wireless updates for a home automation network display - Google Patents

Abstract

In a home automation network for monitoring and controlling domestic alarm systems 13, heating and lighting systems 14 or computer/email systems 15, a portable liquid crystal display 24 showing energy use and security status throughout the home is updated wirelessly, with trigger messages being sent when eg. the user leaves home, a window is left open or an appliance is left on. The display is powered by a photovoltaic cell (33, fig. 2) and maintained by a network manager 3 in a more powerful device via control messages 6, which can also access the internet 9. The user may also control appliances in the network via the display's touch-screen.

Description

Portable display device

Description

The present invention relates to a portable display device, particularly, but not exclusively, for use in a home automation network.

Devices within a home, office or other similar private or public environment are increasingly being interconnected to form local control networks. These networks allow a user to monitor and control devices and appliances, such as alarm systems, heating, ventilation and air conditioning (HVAC) systems, and lighting. These types of network are often referred to as a "home automation network".

Home automation networks are expected to become more common as they can be used to help a user to monitor and control energy usage in the home or office.

However, existing home automation networks can be complex and inconvenient to use.

For example, energy usage can be monitored using a personal computer. However, computer-based systems generally tend dissuade less technically-minded users from taking full advantage of the home automation network to reduce power consumption in the home or office.

Moreover, personal computers tend to be inconvenient to use when user wish to casually and/or continuously monitor energy usage. Desk-top personal computers are not portable and so it can be inconvenient for a user to check energy usage on the spur of the moment, particularly is the computer is located in another room and, even more so, if they need to switch the computer on. Even lap-top computers can be inconvenient to use and, unless mains-powered, run out of power. Regardless of type, using a personal computer tends to consume the very power which the user wishes to conserve.

Fixed displays can be located around the home which allow the user to check and control, for instance, room temperature. However, these types of devices can be inconvenient to use because they tend to be wall mounted. The user cannot carry the device with them and, for example, sit down and use the device. Furthermore, these devices tend to be continuously powered.

One solution is to provide a portable display. However, such a device is either too simple, providing too little functionality, or too complex and costly.

For example, if the device simply presents room temperature without any means of feedback, then the user is unlikely to find the device of practical use. However, if the device allows the user to monitor and control the network, then the device will require additional processing power and wireless communication capability.

However, this leads to increased power consumption and so increases the risk of the device running out of power. Although a mains-powered cradle can be used to recharge the device, this tends to reduce the amount of time that the device is used.

Portable display devices which are used in other applications are known. For example, WO 00/26761 A describes a system for centrally controlling and updating display devices for use in a retail environment. The display device can include a display which uses electronic ink, a wireless receiver and a controller. However, this type of device is not particularly well suited for use in a home automation network.

For example, in a retail environment, information presented on display devices may not change for days or weeks, whereas in a home environment, information required by user can change rapidly over the course of hours or minutes. Moreover, in a retail environment, access to the display device, other than through the central control unit, is limited.

The present invention seeks to provide an improved portable display device which can be used, for example, in a home automation network.

so According to a first aspect of the present invention there is provided a portable display device comprising a display, a controller and a wireless communication interface, wherein the device is configured such that the display presents a succession of static images and wherein the controller is configured to communicate with a processing device via the wireless communication interface, wherein the device further comprises a user input device, wherein the controller is configured, in response to receiving user input while a first static image is presented on the display, to send a message to the processing device to request data and, in response to receiving display data from the processing device, to update the display from the first static image to a second static image using the display data and/or update the display from the first static image to a second static image and to transmit a message to the processing device to indicate that the display has been updated.

Thus, while the portable display device can be used to monitor and control a device or network, such as a home automation network, the status or a model of the display device can be maintained by another, more powerful device elsewhere in the network which can process information on behalf of the display device and so reduce the amount of processing performed by the display device and the amount of power it consumes. Nevertheless, the user can be afforded real-time control in a manner which minimises the chance of old or inaccurate information being presented to the user. The model may relate to data displayed on the screen and/or to data stored in the portable display device.

Preferably, the first and second static images are adjacent images in a sequence or set, i.e. without any intervening or intermediate static image(s).

The display may consume substantially no power or low power when displaying an image. For example, the power required to refresh an image may be no more than about 10 RAh or no more than about I RAh.

The display may be an electrophoretic display, a bistable liquid crystal display, an electrochromic display or an c-paper display.

The short-range wireless communication interface may conform to the Zigbee, Z-Wave, óLowPan, XI0 or LowPower WiFi standard.

The message may comprise a notification that the display has been updated. The message may comprise a request for data so as to allow the display to be updated and the controller is configured, in response to receiving a reply to the request, to update the display. The message may comprise an identifier which identifies a form for filling with data.

The data may include an identifier which identifies a form for filling with data and wherein the controller is configured, in response to receiving said trigger, to retrieve a form stored in memory, to fill the form with the data and to display said filled form. The form may be a page for filling the display.

The device may comprise an energy harvesting device. The controller may be further configured to manage power consumption of the device based upon an amount of harvested power available.

This can help allow the portable display device to operate permanently without the need for charging the device via a wired connection.

The energy harvesting device may comprise a photovoltaic cell.

According to a second aspect of the present invention there is provided a communication interface, for example wireless communication interface, and a controller, wherein the controller is configured to maintain a model of a portable display device and, in response to sending data to a portable display device via the communication interface or receiving a message from a portable display device via the communication interface that portable display device has updated its display has been updated, to update the model.

The controller may be configured to keep a record of a location of a user and to control transmission of the trigger in dependence upon the location of the user, such as whether the user is a home or not at home.

The controller may be configured to keep a record of power available at the portable display device and to limit transmission of data in dependence upon the power available.

According to a third aspect of the present invention there is provided the portable display device and the processing device.

According to a fourth aspect of the present invention there is provided a method comprising receiving user input while a first static image is presented on a display and sending a message to request data and, in response to receiving display data, updating the display from the first static image to a second static image, and/or updating a display from the first static image to a second static image and transmitting a message to indicate that the display has been updated.

According to a fourth aspect of the present invention there is provided a imainftining a model of a portable display device, sending data to the portable display device and updating the model.

According to a fifth aspect of the present invention there is provided a computer program which, when executed by a controller, causes the controller topo the method.

According to a sixth aspect of the present invention there is provided a computer program product comprising a computer-readable medium storing the computer program.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a schematic diagram of a home and a home automation network deployed in the home; Figure 2 is schematic block diagram of a portable display device; Figure 2a illustrates non-volatile memory in a portable display devicc Figure 3 illustrates an example of a face of the portable display device shown in Figure 2; Figures 4a to 4e illustrate examples of different types of screen which can be presented to a user during operation of a portable display device; Figures 5a and Sb illustrate examples of different status bars; Figure 6 is schematic block diagram of a home automation network manager; Figure 7 is a schematic block diagram of a message transmitted by a portable display device to a home automation network manager; Figure 8 is a schematic block diagram of a message transmitted by a home automation network manager to a portable display device; Figure 9 illustrates non-volatile memory in a home automation network manager; Figure 10 illustrates exchange of data between a portable display device and a home automation network manager when initiated by the portable display device; Figure 11 show examples of screens presented to a user during operation of a portable display device; Figure 12 illustrates exchange of data between a portable display device and a home automation network manager when initiated by the home automation network manager; Figure 13 illustrates setting an update rate and/or refresh rate depending on a location of a user; Figure 14 illustrates setting an update rate and/or refresh rate depending on power available in the portable display device; Figure 15 illustrates a first method of setting an update rate and/or refresh rate depending on power available in the portable display device; and Figure 16 illustrates a second method of setting an update rate and/or refresh rate depending on power available in the portable display device; and Referring to Figure 1, a network I is shown comprising a plurality of wireless nodes 2 and a main node 3 (herein referred to as a "home automation network manager" or "home automation box") arranged in, for example, a point-to-multipoint or mesh configuration and deployed in a home 4, e.g. house, flat or other residential environment. However, the network may be deployed in commercial environments, such as shops, offices or hotels, in industrial environments, such as a factory shop floor, and other non-residential environments.

The nodes 2 are connected to the home automation network manager 3 directly or via an optional range extender 5 through respective low-power, low-data rate, short-range wireless data links 6.

In this example, the network I conforms to ZigBeeTM specification and IEEE 802.15.4 physical radio standard. Thus, the nodes 2 can transmit data having a maximum transmit output power of about 100 mW (2OdBm) EIRP, a maximum data rate of about 250 kbps and a range of about 10 to 100 m. However, ZigBeeTM specification and/or IEEE 802.15.4 need not be used and other low-power, low-data rate, short-range wireless standards, for example having similar power, bandwidth and range characteristics, may be used.

The network manager 3 serves as a coordinator for the network I providing networking facilities, such as device and service discovery caching and, optionally, channel management and trust centre operations.

The network manager 3 also provides TCP/IP gateway functionality via hub 7 and broadband modem 8 to an external network 9. As shown in Figure 1, the external network 9 can be used to access, for example, telecommunications company server(s) 10, web server(s) 11 and e-mail server(s) 12.

The network manager 3 may implement gateway management and ZigBee gateway device layers, together with gateway remote interface protocol (GRIP) for allowing external hosts to access applications running on the network manager 3 and ZigBee Internet Transport Layer (ZIPT) for allowing the network to be extended over an IP network.

The network manager 3 may also provide an OSGi environment for running Java applications. The home automation network manager 3 may be configured and upgraded using TR-069 or other protocols for remote management of end-user devices.

As shown in Figure 1, the nodes 2 can be grouped according to different uses or applications including, for example, security-related devices 13, power control and profiling devices 14 and configuration and analysis devices 15.

The security-related devices 13 may include an alarm system 16, intrusion detection sensors such as passive infrared detectors 17 and floor-based pressure sensors 18, and also an entry or access panel 19 for activating and deactivating the alarm system 16.

The power control and profiling devices 14 may include one or more power monitoring devices 20 for detecting current flowing through mains power cable(s).

The power monitoring devices 20 may be installed at various points throughout the electrical power distribution system in the home. For example, a device 20 may be installed in a distribution board (not shown) or immediately downstream from a distribution board, i.e. between the distribution board and plug sockets, for measuring power consumption for the whole home. A device 20 may be provided for each or some circuits, e.g. lighting circuit, first floor circuit, room circuit etc. Power monitoring device(s) 20 may have sockets 21 for receiving plugs 212 for supplying power to appliances 22, such as television sets, media players, game consoles, computers, microwave ovens and other household (or office) appliances.

Thus, power monitoring device 20 may be take the form of fixed, in-wall plug sockets or multi-way (e.g. 4-way) extension leads. Power monitoring devices 20 may be installed in line and may control power, e.g. allowing power to be switched "on" and "off'. Power monitoring devices 20 may be passive devices, which only monitor power, e.g. by measuring current flowing through a cable.

As will be explained later, power monitoring devices 20 can report power consumption to the home automation network manager 3, e.g. via a wireless link 6, which can gather data on energy usage in the home 4.

The configuration and analysis devices 15 can include a personal computer 23 (which may or may not be a node 2 forming part of the wireless network 1) and a portable display device 24.

The display device 24 cooperates with the home automation network manager 3 to provide the user with information about the network 1, for example, notifying or alerting the user about the status of the network I or specific nodes 2. For example, the display device 24 can display energy usage. Furthermore, the display device 24 can warn the user of potential security risks and/or unnecessary wastage of power, such as notifying the user that an external door has been left open or unlocked, that the heating has come on and a window has been left open or that an appliance has been left on when the occupier is about to leave home 4.

Furthermore, the display device 24 can be used to notify the user about external events or obtain data from external (e.g. web-based) sources of information. For example, the display device 24 can be used to notify the user that an-email has arrived or obtain a weather forecast.

The display device 24 can be configured to pull data from the network manager 3 depending on user preferences.

The display device 24 can control or influence operation of devices 2 in the network I. The device 24 can be linked to specific devices 2, such as the alarm system 16, and be provided with information about those devices 2 based on user preferences and send commands to control devices, e.g. switch on or off certain devices (e.g. lights) and arm/disarm the alarm system 16. In some embodiments, connection of the display device 24 to the network I or to network manager 3 can be used to infer that the user is at home and, thus, control whether or not to push data to the display device 24, switch on or off certain devices and arm/disarm the alarm system 16.

-10 -The display device 24 can inform the network manager 3 about its status, e.g. available power, which can affect whether or how often data (including software updates) is transmitted to the device 24 and whether the data is presented to the user.

Thus, the display device 24 can be used as a convenient source of information about energy usage, security and other services, as well as providing a control interface.

Notwithstanding this, it can provide enhanced levels of functionality without the need for considerable processing power and amounts of electrical power.

By harvesting power, e.g. by using a solar cell, it can operate continuously without the need for recharging using a cradle or a cable and, thus, afford the user even greater flexibility to use the display device 24 throughout the home 4.

The display device 24 need not be used in a home automation network. For example, the display device 24 can be used in conjunction with a home or office computer to be notified about incoming c-mails, weather report updates and so on.

Referring to Figures 2 and 3, the portable display device 24 has circuitry 25 which has been adapted to consume low amounts of power.

The display device 24 includes a low-power display 26, for example, in the form of a bistable liquid crystal display or other display which consumes no or low amounts of power when displaying, updating and/or refreshing an image, a low-power wireless network interface 27, for example, in the form of ZigBeeTM compatible wireless transceiver conforming to IEEE 802.15.4 2.4 and operating at 2.4 GHZ/868 MHZ, user input devices 28, for example, including three buttons 28, 282, 283, a processor 29, non-volatile random access memory 30 and volatile random access memory 31. The display 26 may have a diagonal dimension of about four inches (about 10 centimetres). However, a smaller display, e.g. three-inch display, or larger displays may be used. As will be explained later, other forms of low-power display 26 and low-power wireless network interface can be used. Furthermore, the user input devices may include additional or fewer buttons. Additional or -11 -alternative user input devices may be provided, such as scroll wheel, joystick, touch screen or touch pads, slider bar etc. The processor 29 outputs signals to the display 26, receives and processes signals from the user input device(s) 28 and exchanges data with the wireless transceiver 27.

The processor 29 and other parts of circuitry 25 are powered by a solar cell 33 through a rechargeable battery 34or other energy storage, e.g. capacitor. An example of a suitable solar cell is an ASI� OEM Indoor Solar Module available from Schott Solar. Additional or alternative energy harvesting devices may be used.

Optionally, a socket 36 for receiving power from cradle or charger (not shown) can be included. This can be used to re-charge the device in exceptional circumstances, e.g. when a major software update is needed. As shown in Figure 2, the processor 29 can monitor status of the battery 34 and/or be provided with a signal 37 to indicate whether the battery 34 is being charged.

The device 24 may include additional input/output devices, such as a speaker 38 and light emitting diode(s) 39. These may be used to notify or warn the user, e.g. of loss of connection. Furthermore, the display 26 may be a touch-sensitive display.

Referring also to Figure 2; the processor 29 can receive data 40 for display (and/or for other forms of output, e.g. sound) and store the data in the non-volatile random access memory 30. For example, the data 40 may data in a mark-up language, such as XML.

The non-volatile random access memory 30 also stores templates 41 which can be combined with the data 40 to provide screen data for display or audio for play back.

The display device 24 is not intended to be used and is not used as a real-time, high-bandwidth playback device, e.g. receiving audio and/or video content wirelessly from a source and rendering the content in real time. However, the templates 41 or other locally-stored data may include audio and/or video content, e.g. a simple snbmation or speech, which can be played to the user. For example, this can be -12 -used to provide speech, e.g. "The alarm system is deactivated" or "The amount of power consumed is" and add synthesised speech specifying a value. However, this may add to power consumption of the device 24 and so this type of audio-visual content can be omitted.

The non-volatile random access memory 30 also includes operating software 42 for controlling the display device 24.

The display device 24 is configured so that it can operate, e.g. without the need for recharging from a mains-powered charger (or other similar external source, such as a computer via a USB connection) or replacing its battery, for an extended period of time, e.g. exceeding a year or even several years. For example, this may include calculating how much power the display 26, wireless interface 27, processor 29 and memory 30, 31 consume for a given number sent and received data packets and given number of screen refreshes. The given number of data packets and given number of screen refreshes may be an average amount or an upper limit. This may include choosing, for example, the type and si2e of the display 26, the type and power of the transceiver and the operating voltage and clock rate of the processor for a battery of given capacity. Additionally or alternatively, the capacity of battery may be chosen based on the expected power consumption and expected self-discharge rate. The stored power may take into account trickle charge form an energy harvesting device, such as a solar cell.

In particular, the components of the display device 24, in particular the display 26, wireless interface 27, processor 29, memory 30, 31, solar cell 33 and battery 34, can be chosen and/or configured based upon a consideration of energy budget for the display device 24. This is achieved by considering the power stored in the battery 34, power harvested by the solar cell 33, power consumed by the other components and power losses (e.g. battery self-discharge) averaged over a period which, in this case, is a day. However, other periods may be considered. The power can be expressed in amp-hours (Ah).

-13 -An estimate of the power harvested by the solar cell 34 may be based on an assumption of the amount of illumination the device 24 will receive during a day.

For example, it can be assumed that the device 24 may not be illuminated at all for a night-time period, e.g. lasting about 8 hours, and that the device may be illuminated by direct sunlight (typically providing upwards of about 1000 Lux) for a proportion of a day-time period and by indoor lighting (typically providing about 50 to about 500 Lux) for the rest of the day-time period.

For example, the power consumed by the display 26, such as 1/8 VGA cholesteric LCD, per screen refresh may be of the order of magnitude of I RAh (i.e. between about 1.0 and about 9.9 RAh), for example about 7 RAh. The power consumed by the wireless interface 27, such as a ZigBee/802.15.4 Network Processor, per transmit or receive operation may be of the order of 10 RAh, for example about 20 RAh. The power consumed by the wireless interface 27 when not in use may be of the order of magnitude of 0.1 RAh (i.e. between about 0.10 and about 0.99 RAh), for example about 0.1 RAh. The solar cell 33 having an area of about 50 cm2 may generate the order of magnitude of 100 RA per day (i.e. between about 100 and about 999 RA per day), for example about 500 RA per day (i.e. 12,000 RAh). The battery 34 may store about 21,000 mAh. Thus, the power harvested by the solar cell 33 would exceed the power consumed by the display 26 and the wireless interface 27 performing tens or hundreds of operations (i.e. refreshes/updates or transmits/receives) in a day. Therefore, the device 24 has the potential to operate for many years without recharging or replacing batteries.

The display device 24 may be updated and/or refreshed one or more times a day.

Typically, during normal operation, the display device 24 may be updated/ refre shed, on average, about once every hour or about once every couple of hours.

For example, the display 26 may be updated or refreshed between about 10 to 30 times per day.

-14 -The display 26 may be updated or refreshed less frequently, for example, if the user is not at home and/or if the amount of power stored in the battery is low. Thus, the display might, under certain circumstances, change only once or twice a day. In rare circumstances, the display may not be updated or refreshed at all during a 24-hour period.

The display 26 may be updated or refreshed more frequently, particularly if the user operates the display device 24. More frequent updates/refreshes can be performed, for example, about once every five minutes.

Figure 3 illustrates an example the face of the display device 24. However, the display device 24 may be differently arranged. For example, the display 26 may have a different si2e or aspect ratio, the type(s) or number of user input device may differ and the type or number of energy harvesting devices may vary. Also, the design and configuration of what is presented on the display 24 may also differ.

Referring to Figure 3 and 4a, the display 26 presents a home screen 43 (or home "page" or "form") which includes a status bar 44 arranged across the top of the screen, first, second and third main display zones 45, 45 lying in bands across the middle of the screen and a menu bar 46 sitting at the bottom of the screen.

In this example, the display zones 453 relate to security, energy saving and messaging. However, fewer or additional zones may be used. Some or all of the zones may relate to other functions, contain different information and/or use other icons. For example, one of the zones may relate to indoor and/or outdoor temperature. Zones may contain live data, such as energy usage or temperature readings.

As shown in Figure 3 and also Figure Sa, the status bar 44 includes a signal strength icon 47, a connection icon 48, a logo 49 and a power icon 50. Thus, the status bar 44 provides, at a glance, information about the status of the display device 24.

-15 -As shown in Figure 5b, if the display device 24 is not connected and/or if the display device 24 is running low on power, then the user can be warned through appropriate icons 47, 48, 50.

Additionally or alternatively, the status bar 44 can present other information such as date and/or time of last update.

Referring still to Figure 3, the main display zones 453 illustrate high-level options or functions which are available to the user through the display device 24.

The menu bar 46 displays possible options 46, 462, 463 which are available and which are aligned with respective keys or buttons 28, 282, 283. Thus, the keys 28, 282, 283 are "soft-keys" whose function can change. If a touch-sensitive display is used, then the main display zones 453 may behave as buttons which can be "pressed" and so provide user input.

Referring to Figure 4b, an application screen 47 may include a status bar 48 which is the same or different to the status bar 44 shown earlier. The application screen 47 can include a navigation bar title 49 which provides an indication as to what information is being displayed in a main display portion 50. The application screen 47 also includes a menu bar 51.

Referring to Figure 4c, a more-detailed application screen 52 may include a status bar 53 which is the same or different to the application screen status bar 48. The application screen 52 can include a navigation bar title 54, a smaller main display portion 55 and a sub-main portion 56, as well as a menu bar 57.

Referring to Figure 4d, a more-detailed application screen 58 may include a status bar 59, a navigation bar title 60, a main display portion 61 and a page zone 62, for example, including a line of dots 63, one 64 of which is highlighted to indicate which page the user is currently viewing. The more-detailed application screen 58 also includes a menu bar 65.

-16 -Referring to Figure 4e, a special application screen 66 may be provided which includes a special navigation bar 67, a main zone 68 and a menu bar 69.

The display 26 may divided into independently-updatable portions. For example, these portions may include a portion corresponding to the status bars 44, 48, 54, 59.

Thus, the whole display 26 need not be updated if only one part of the screen (i.e. a "sub-screen" or "frame") changes, but the rest of the other parts of the screen (i.e. other frames) do not change. This can help to save power.

The screens 43, 47, 52, 58, 66 and status bars 44 are examples. The number of screens, their layout and design may be changed.

Referring to Figure 6, circuitry 70 of the home automation network manager 3 is shown in more detail.

The network manager 3 includes a low-power wireless network interface in the form of a ZigBeeTM wireless transceiver 71, user input device(s) 72, e.g. in the form of one or more keys or buttons (not shown), output device(s) 73, e.g. the form of one or more light emitting diodes (not shown), a processor 74, for example, an ARM-or Power-PC-based processor, non-volatile random access memory 75, volatile random access memory 76 and a wired network interface 77.

The network manager 3 is mains-powered, but may have a rechargeable battery (not shown) as a back-up supply. The home automation network manager 3 may also provide a cradle for the display device 24 (Figures 1, 2 & 3) and supply power for charging the display device battery 34 (Figure 2).

Referring also to Figure 7, the network manager processor 74 can send a message 78 to the display device 24 (Figures 1, 2 & 3) which may include screen update data 79, ancillary data 80, which is not presented to the user but may be required for other purposes such as formatting, and/or a refresh command or "trigger" 81. A message 78 can be contained in one data packet 82 or can be divided between more than one data packets 82.

-17 -As will be explained later, one message 78 can contain the screen update data 79 and, optionally, ancillary data 80 and another, different message 78 can be sent later which contains a corresponding command 81 to refresh the display using the screen update data 79. This can be used to manage energy consumption of the display device 24 (Figures 1, 2 & 3), for example, by avoiding refreshing the display 26 (Figure 2 & 3) when the user is not at home 4 (Figure 1).

A message 78 may include template update data 82 and a template update command 83. Template update data 82 is usually sent much less frequently than screen update data 79. However, this mechanism can be used to update the templates 41 (Figure 6a) stored in the display device 24 (Figures 1, 2 & 3) if necessary and, for example, when power at the display device 24 (Figures 1, 2 & 3) is plentiful.

Referring to Figures 6 and 8, the processor 74 can receive a message 85 from the display device 24 (Figures 1, 2 & 3) via the wireless transceiver 71 which can include a request 86 for screen data, an acknowledgement 87, e.g. to acknowledge an alert, a command 88, e.g. to control a device, and/or an alert 89. A message 85 can be sent in one data packet 90 or can be divided between more than one data packets 90.

Referring to Figure 9, data received from the display device 24 (Figures 1, 2 & 3), from the nodes 2 (Figure 1) and/or from the internet 9 (Figure 1) can be processed and stored in memory 75.

The network manager 3 stores a copy 91 of data 40 (Figure 2a) stored in the display device 24 (Figures 1, 2 & 3). The network manager 3 may also store a copy 92 of the set of templates 41 (Figure 2a) currently stored at the display device 24 (Figures 1, 2 & 3) and a new set of templates 93 which are ready for uploading to the display device 24 (Figures 1, 2 & 3) or which have been uploaded by not activated.

The network manager 3 also stores a copy 94 of data or screen (or sub-screen(s)) currently displayed by the display device 24 (Figures 1, 2 & 3) and/or an indication -18 -of which screen is currently displayed by the display device 24 (Figures 1, 2 & 3), for example, using a page or template identifier.

The network manager 3 also stores other display device-related data 96, such as information 97 relating to the position of the user and/or the display device 24 (Figures 1, 2 & 3) and information 98 about the amount of power available, e.g. which is stored and/or which is currently being generated by the solar panel 33 (Figures 2 & 3). The network manager 3 may also store preference data 99, e.g. which can be used to filter data obtained from other devices 2 and via the internet 9. The home automation network manager 3 may also cache alerts 100 and other forms of notifications which have yet to be sent to the display device 24 (Figures 1, 2 & 3). The network manager 3 may also store credential data 101 for pairing and establishing a secure link with the display device 24 (Figures 1, 2 & 3).

The network manager 3 may also store a copy 102 of the software 42 (Figure 2a) stored at the display device 24 (Figures 1, 2 & 3) and, if available, new software 103 for uploading.

Using at least some of this data, the network manager 3 keeps a model 104 of the display device 24 (Figure 1). For example, the model 104 may be a complete model of the state of the device including a current record of all data 40 (Figure 2a) and templates 41 (Figure 2a) stored at the display device 24 (Figures 1, 2 & 3) and data presented to the user on the display 26 (Figures 2 & 3). However, the model 104 may be partial, for example, relating to only what is displayed to the user.

In addition to data relating the display device 24 (Figures 1, 2 & 3), the network manager 3 also stores data 105 which need not relate to the display device 24 (Figures 1, 2 & 3), such as data relating to other devices 2 (Figure 1).

The non-volatile random access memory 75 also includes operating software 106 for controlling operation of the home automation network manager 3.

-19 -Referring again to Figures 1, 2 and 3, the display device 24 is paired with the network manager 3. This may be achieved automatically when the devices 3, 24 are first switched on or in response to user instruction.

Once paired, the user may select preferences, e.g. about the types of notifications they wish to receive, e.g. about particular security risks, particularly high energy usage or incoming c-mails.

The display device 24 can be updated and/or its display 26 refreshed either in response to a trigger from the display device 24, usually resulting from user input, or from the network manager 3.

Referring also to Figure 10, operation of the display device 24 and home automation network manager 3 in response to a trigger from the display device 24 will first be described.

As shown in Figure 10, an event occurs at the display device 24 (step S IA).

For example, the user may press a button 28, 282, 283 to request information. If the display device 24 has not been used for a period of time (e.g. between about one or five minutes), pressing a button 28, 282, 283 may also have the effect of waking-up' the processor 29. The event need not be initiated by the user. For example, the event may relate to the ambient light level or amount of stored power available.

In response to the event, the display device processor 29 prepares and transmits a message 85 using the wireless transceiver 27 (step S2). In this example, the message includes a request 86 for an application screen 47 (Figure 4b).

The network manager 3 receives the message 85 via its wireless transceiver 71 and processes the message 85 (step S3).

According to the content of the message 85, the network manager processor 74 may retrieve data from memory 75 (step 54A), send a request 108 to an external source -20 - (step S4BI) or to a device 2 within the network I (step S4CI) and receive a response (step S4B2/S4C2).

The network manager processor 74 may process the data 109 (steps S5), for example, to extract and format data, and transmits a message 78 containing screen data and, in the same or subsequent message 78, a command to refresh the display (steps S6 & S7) via the wireless interface 71.

The network manager processor 74 updates its model 104 (Figure 9), for example by updating its copy 91 of the data stored at the display device 24, its copy of the screen and/or its indication of what the display is showing (step S8).

The display device 24 receives the message(s) 78 via its wireless transceiver 27 and stores the data (step S9) and, if it receives the command, refreshes the display 26 (step Sb). Thus, in the example, that the user requests an application screen 47 (Figure 4b), then the application screen 47 (Figure 4b) is displayed.

As shown in Figure 11, this process can be repeated to navigate through a set of screens or pages. During each stage of navigation, the network manager 3 keeps a current model 104 (Figure 9) of the display device 24.

Data being displayed may require effort to obtain and/or compute. However, the display device 24 need neither store or obtain the data needed, nor carry out computations. Instead, the network manager 3 performs these operations on its behalf.

Thus, if the display device 24 requires data to be obtained or processed, it need only send a short command to the network manager 3 which has enough information to execute the command.

For example, as shown in Figure 11, an energy application page 47 may show the amount of energy that has been used that day, the amount of energy that has been consumed in the last three months and predict the amount of energy which will be -21 -consumed based upon current usage. Obtaining these values may require taking readings from the power monitoring devices 20 (Figure 1) or looking up stored readings and processing the readings. This can be done by the network manager 3 or application on a web server. Thus, the display device 24 does not require the processing power, memory storage or power to perform these steps. By requesting a screen, it can instruct the network manager 3 to obtain these values and, once obtained, display a screen containing the values.

Referring now to Figures 1, 2, 3, 6 and 12, operation of the display device 24 and home automation network manager 3 in response to a trigger from the home network manager 3 will now be described.

In this case, an event occurs at the network manager 3, a server 11, or at a device 2 within the network I (step SIB, SIC or SID). For example, the network manager 3 may detect or initiate a change in network settings, an e-mail may have arrived at an e-mail server or a sensor may have been triggered. The events may be spontaneous or the network manager 3 may periodically poll devices and servers.

The network manager processor 74 processes any received (steps S5), and transmits a message 78 containing screen data and a command to refresh the display (steps S6 & S7) and updates its model 104 (Figure 9) (step S8) in the same way as that described earlier. As mentioned earlier, the network manager 3 can filter triggers and may not generate a message if it does not comply with the user's preferences.

The display device 24 receives the message(s) 78, stores data (step S9) and refreshes the display 26 to alert the user (step Sb).

The display device 24 can send an acknowledgement, i.e. a message 85 containing an acknowledgement 87 (Figure 8), to the network manager 3 to confirm receipt of alert. The network manager 3 need not send a further reply, i.e. need not perform steps S6 & S7.

-22 -Events and triggers can be generated by the display device 24 and by other devices 2, 3 inside or outside the network 1. However, the display device 24 need not be updated or the screen refreshed if, for example, power is low or the user is not at home 4.

Updates and refreshes can be controlled in one or more ways, as will now be explained.

Referring to Figures 1, 6 and 13, before sending any data to the display device 24, the network manager processor 74 can check the position 97 (Figure 9) of the user and/or display device 24 to determine whether they are at home and, if not, suppress sending data and/or a refresh command.

The location of the user and/or display device 24 can be inferred from whether a signal is received from the display device 24 and/or whether the user has activated the access panel 19 when leaving from or arriving at home 4. Typically, positioning is coarse, e.g. whether the user is at home or not at home. However, the position of the location can be more accurate, e.g. which room the user occupies. Additionally or alternatively, position can be measured directly, e.g. using sensors 17, 18, and/or range extender 5. Thus, if the user is at home, but not in the same room as the display 24, then updates an/or refreshes may be suppressed.

As shown in Figure 13, the network manager processor 74 may suppress transmitting screen data and refresh command until the user returns home.

If the user is not at home 4, but the display device 24 has been left behind at home 4, then screen data (but not a refresh command) or other data, e.g. software update, can be sent to the display device 24.

There may be situations when power is in plentiful supply at the display device 24, for example when the display device 24 is in strong light and is not being used.

This opportunity can be used to send large amounts of data, e.g. to update software.

-23 -Conversely, there may be situations when power is scarce, for example, after long periods of use in low-light conditions. Thus, the network manager 3 can take steps to conserve power.

Referring to Figures 1, 6 and 14, the network manager processor 74 can inspect available power 98 (Figure 9) which can be periodically reported by the display device 24 and/or estimated based on earlier readings and usage.

If the amount of power (e.g. stored and/or instantaneous measured) is above a threshold (step S5BI), then the network manager processor 74 sends messages 78 normally (step S5B2).

On the other hand, if the amount of power falls below the threshold (step S5B2), then the network manager processor 74 may suppress sending messages where possible (step S5B3).

Two or more thresholds can be used to distinguish between high, normal and low amounts of power having high, normal and low update and refresh rates.

Referring to Figure 15, the network manager processor 74 may suppress sending messages by determining whether a message 78 is important (step S5B3AI) and, if not, waiting for better conditions before sending the message 78 (step S5B3A2).

Referring to Figure 16, the network manager processor 74 may suppress sending messages by scheduling data (step S5B3BI) and sending the data at schedule times, e.g. when it is expected that conditions will be better (steps S5B3B2 & S5B3B2).

Combination of power saving techniques can be used. For example, the home automation network manager 3 can send more than one message at different times, each message corresponding to separate screen update. However, the manager 3 does not include any triggers. Instead, the manager 3 can send a message with a single trigger which causes all of the updates or accumulated updates (i.e. some updates may overwrite a previous update) to occur at the same time.

By niininiising power consumption and harvesting power, the display device 24 can be used to keep the user constantly informed about devices 2,3 and appliances in the home 4 and updated with news and messages from external sources 10, 11, 12.

Moreover, by using the home automation network manager 3 to carry out data gathering, storage and processing on its behalf and to monitor the power available, the display device 24 is able to further reduce its power consumption without necessarily sacrificing its ability to present complex data to the user and provide an interface for controL It will be appreciated that many modifications may be made to the embodiments hereinbefore described.

Although the network I hereinbefore described is deployed in a residential environment, it may be deployed in an office or other suitable type of environment.

Other forms of display which consume substantially no power or low power when displaying an image may be used. For example, electrophoretic, bistable liquid crystal, electrochromic displays or c-paper can be used. Examples of such displays include Quick Response Liquid Power Display (QR LPD) c-paper available from Bridgestone Corp. Electronic Paper Display available from B-Ink, cholesteric liquid crystal displays available from Fujitsu Frontech, Kent Displays Inc., Magink Display Technologies and Varitronix International, bistable liquid crystal displays available from Nemoptic, ZBD Displays Ltd. and Varitronix International, and electrochromic displays available from Ntera, electrophoretic available from SiPix Imaging.

Zigbee and/or IEEE 802.15.4 standards need not be used. For example, a wireless network interface based on the Z-Wave, 6LowPan, X10, LowPower WiFi or other standard can be used. Nodes can transmit power at powers between about 3 mW and about 100 mW. Nodes may transmit at data rates of between about 10 kbps and 100kbps or more. The nodes may have a range of about 10 to 100 m. -25 -

Other forms of devices and appliances can be added to the network. For example, these may include HVAC appliances, such as boilers and air conditioning units, electricaliy-dñven blinds and white goods, for example fridges and washing machines. Some devices shown in Figure 1, such as pressure sensors, may be omitted.

Claims (18)

1. Claims 1. A portable display device comprising: a display; a controlier and a wireless communication interface; wherein the device is configured such that the display presents a succession of static images and wherein the controller is configured to communicate with a processing device via the wireless communication interface; wherein the device further comprises: a user input device; wherein the controller is configured, in response to receiving user input while a first static image is presented on the displa to send a message to the processing device to request data and, in response to receiving display data from the processing device, to update the display from the first static image to a second static image using the display data; and/or update the display from the first static image to a second static image and to transmit a message to the processing device to indicate that the display has been updated.
2. 2. A device according to r]sini 1, wherein the device is configured such that the display permanently presents an image.
3. 3. A device according to clsini I or 2, wherein the display is a bistable liquid crystal display.
4. 4. A device according to any preceding rlsini, further comprising an energy harvesting device, wherein the controller is further configured to manage power consumption of the device based upon an amount of harvested power available.
5. 5. A device according dnitn 4, wherein the energy harvesting device comprises a photovoltaic cell.

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6. 6. A device according to any preceding claim, wherein the message to request data comprises an identifier which identifies a form for filling with data.
7. 7. A device according to any preceding claim, wherein the display data includes an identifier which identifies a form for filling with data and the wherein the controller is configured to retrieve a form stored in memory, to fill the form with the data and to display said filled form.
8. 8. A device according to claim 6 or 7, wherein the form is a page for presenting on the display.
9. 9. A device according to any preceding claim, wherein the wireless communication interface is a short-range communications interface, optionally comprising a transceiver configured to conform to the ZigBeeTM specification and IEEE 802.15.4 physical radio standard.
10. 10. A device according to any preceding claim, wherein the controller is configured to update the display in response to instruction by the processing device.
11. 11. A processing device including: a communication interface; and a controller; and wherein the controller is configured to maintain a model of a portable display device and, in response to sending data to a portable display device via the communication interface or receiving a message from a portable display device via the communication interface that portable display device has updated its display, to update the model.
12. 12. Apparatus according to claim 11, wherein the controller is configured to so keep a record of a location of a user and to limit transmission of data in dependence upon the location of the user. -28 -
13. 13. Apparatus according to rlsini 11 or 12, wherein the controller is configured to keep a record of power available at the portable display device and to limit transmission of data in dependence upon the power available.
14. 14. A system comprising: a portable display device according to any one of r]sinis I to 10; and a processing device according to any one of rltinis 11 to 13.
15. 15. A method comprising: receiving user input while a first static image is presented on a display; and: sending a message to request data and, in response to receiving display data, updating the display from the first static image to a second static image; or updating a display from the first static image to a second static image and transmitting a message to indicate that the display has been updated.
16. 16. A method comprising: imdnftining a model of a portable display device; sending data to the portable display device and/or receiving a message from a portable display device that the portable display device has updated its display; and updating the model.
17. 17. A computer program which, when executed by a controller, causes the controller topo a method according to ckini 15 or 16.
18. 18. A computer program product comprising a computer readable medium storing a computer program according to dsini 17.