GB2572577A

GB2572577A - A sensor reset device

Info

Publication number: GB2572577A
Application number: GB1805481.7A
Authority: GB
Inventors: Shermer John
Original assignee: Lightwaverf Tech Ltd
Current assignee: Lightwaverf Tech Ltd
Priority date: 2018-04-04
Filing date: 2018-04-04
Publication date: 2019-10-09
Also published as: GB201805481D0

Abstract

Device 1 comprises a housing 10 with an aperture 24 and shutter (e.g. 11 of figures 6-8), which in operation controls the amount of light reaching passive infrared sensor (PIR) 2, effectively resetting the sensor. The IR sensor element is thus more sensitive to movements within its field of view, so for example a stationary person is not ignored by the PIR, which are often receptive to changing IR levels. The sensor 2 may operate as a motion sensor to switch e.g. lighting circuits, preventing wasteful energy use while avoiding undue deactivation. A fixing mechanism 101 e.g. adhesive may retro-fit the device to sensor housing 23. The shutter may be a rotating or oscillating mechanical member, driven at an appropriate frequency between open and closed positions, or e.g. a liquid-crystal device with tuneable opacity, and a power source may scavenge power from the environment.

Description

Title: A sensor reset device

Description of Invention

Embodiments of the present invention relate to a reset device for a sensor, and a combination of a sensor and the reset device.

Instead of being switched on/off or put in a ‘standby’ mode manually, it may be more appropriate for an electrical system, such as lighting or a recording device, for example, to be triggered automatically by a sensor. Motion sensors are commonly used to control lighting, for example, responding to someone entering or leaving a room, or in anti-trespass systems and the like.

It is increasingly common to use sensors to control devices - a touch-free approach, i.e. switching on devices via a voice command, hand-clap or other motion, is convenient and hygienic.

Triggering systems automatically using a sensor saves time and energy; both physical exertion by the user - accessing switches and the like -and the cost of energy bills can be reduced. An electrical system which is triggered by a sensor only expends energy when required, preventing wasteful usage such as leaving the house with the lights still switched on, or forgetting to adjust the central heating when going away on holiday and the like.

Passive Infrared Sensors - PIRs - register infrared radiation impinging on them and respond to changes in IR light.

Infrared light level changes due to a temperature gradient; a short-lived hotspot, for example, would indicate the presence and departure of an Infrared light emitting entity, such as a person or animal or other object passing through a field of view of the PIR. PIRs, therefore, effectively capture a thermal image of an area.

As PIRs are commonly only configured to be receptive to changing IR levels, a stationary person occupying a room for example, will after a time, be ignored by a PIR. The PIR will have redefined the background levels of the thermal image created, to incorporate the static occupant. Automated lighting or heating, for example, which is triggered by the PIR, may be deactivated unwantedly while someone is still in the room. This can be inconvenient and could be unsafe, if automatically triggered lighting is the only form of lighting available, for example.

Moving around rapidly causes a change in the thermal image and the person to be re-registered by the PIR; however such action diminishes one of the primary returns of a touch-free system (i.e. wasting as much, if not more, time and energy than simply walking over to a light switch), especially if the sensor redefines the background levels frequently enough to require repeated movement.

The present invention seeks to alleviate one or more problems associated with PIR or other such sensors.

Accordingly, an aspect of the invention provides a reset device for resetting a passive infrared sensor, the device comprising: a housing at least partially defining a reset device aperture; and a shutter mounted with respect to the reset device aperture and operable between a closed and an open configuration, wherein the housing is configured to be mounted with respect to a sensor element of a passive infrared sensor such that operation of the shutter between the open and closed configurations alters the mount of infrared light transmittable through the reset device aperture to the sensor element.

The reset device may further comprise: a controller configured to operate the shutter between the open and closed configurations at a predetermined frequency.

The shutter may include a device with a tuneable opacity.

The shutter may include a mechanical device.

The mechanical device may include a rotating or oscillating member.

The reset device may further include a power source which is configured to scavenge power from the environment.

The reset device may further include a receiver or transceiver configured to receive one or more instructions to control an aspect of the operation of the shutter.

Another aspect provides a passive infrared sensor in combination with a reset device.

Embodiments of the present invention are described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a side view of a sensor;

Figure 2 shows an end view of the sensor of figure 1;

Figure 3 shows a schematic view of the components of a sensor;

Figure 4 shows a side figure of a sensor and reset device;

Figure 5 shows an end view of a reset device (and sensor in phantom);

Figures 6-8 show the operation of a shutter;

Figure 9 and 10 show different shutters;

Figure 11 shows a schematic view of the components of a reset device; and

Figure 12 shows a schematic view of a reset device communicating with other devices.

With reference to figures 1 to 9, embodiments of the present invention include a reset device 1 as generally indicated in figure 1, which is configured to reset a sensor 2, such as a passive infrared sensor (PIR sensor) 2.

The sensor 2 may include a sensor element 22 (see figure 3, for example) located within a housing 23 (see figures 1 and 2, for example). The sensor element 22 may be positioned within the housing 23 with respect to one or more reflectors (such as mirrors) which are configured to direct light (which may be infrared light) towards the sensor element 22. The sensor element 22 may be an element which is sensitive to infrared light, for example. The sensor element 22 is located with respect to an aperture 24 (see figures 1 and 2, for example) defined by the housing 23 through which light (such as infrared light) is configured to pass. The aperture 24 may be provided with a cover or lens 25 which may be configured to permit the transmission of light (which may be infrared light) from outside of the housing 23 to the sensor element 22 and/or one or more reflectors.

Therefore, whilst the sensor 2 could take a number of different forms, the sensor 2 is configured to receive light (such as infrared light) and provide a transmission path for that light to the sensor element 22, at which the light is sensed.

The sensor element 22 is configured to output a signal which is dependent on the impinging light thereon (and may be configured to output a signal which is dependent on the impinging infrared light thereon). The sensor element 22 may be connected to an electrical circuit 26 (see figure 3, for example) which is configured to process the output from the sensor element 22. This may include, for example, generating a light (e.g. infrared light) profile for the light received by the sensor element 22 and to detect changes therein over a predetermined period of time. In some embodiments, a threshold for changes is provided such that small changes are ignored by the electrical circuit 26. When a change in the light profile is detected by the electrical circuit 26, then the sensor 2 may be configured to perform and/or cause the performance of one or more actions.

For example, when a change in light profile is detected, the electrical circuit 26 may open a switch 27 or close a switch 27, or start/reset a timer which may be configured to open or close a switch when the timer runs out. The switch 27 may be part of the electrical circuit 26 or part of some other part of the sensor 2. The switch 27 may be configured to actuate a power circuit to control another device - such as a light.

The sensor 2 may, therefore, be configured to operate as a motion sensor, using infrared (i.e. thermal) imaging to identify changes in a field of view of the sensor 2. The field of view of the sensor 2 may be defined, in part, one or more of the sensor element 22, the aperture 24 and/or the cover or lens 25 and/or the one or more reflectors of the sensor 2.

The sensor 2 may form a thermal image of the environment within its field of view. If an infrared (e.g. heat) emitting object is stationary in the field of view of the sensor 2, then that object may be included in that thermal image. If the object remains stationary between captured thermal images, then the sensor 2 may view that object as being part of the background to the thermal image. In other words, the sensor 2 may identify no substantial change in the infrared images captured by the sensor element 22 including that object.

The sensor 2 may be configured to actuate the switch 27 if no movement is detected by the sensor 2 or if no movement is detected by the sensor 2 for a predetermined period of time. Therefore, any power circuit which is connected to that switch 27 may be deactivated by the sensor 2 if no movement is detected or no movement is detected for a predetermined period of time.

Components of the reset device 1 may be provided within a housing 10 (see figures 4 and 5, for example). The housing 10 may include a fixing mechanism 101 (such as an adhesive 101) configured to secure the reset device 1 with respect to the sensor 2 (as shown in figures 4 and 5 for example - with the sensor shown in phantom in figure 5). The fixing mechanism 101 may include one or more other elements such as one or more screws, bolts, clips, or the like.

The reset device 1 may be configured to be retrofitted to an existing sensor 2. Alternatively, the reset device 1 may be an integral part of the sensor 2 and the reset device 1 may, therefore not have a separate housing 10 but may share the housing 23 of the sensor 2.

The reset device 1 may be configured to be secured or otherwise mounted with respect to the sensor 2 such that the whole or a part of the transmission path for light to the sensor element 22 is covered by the reset device 1. This may include, for example, the reset device 1 covering at least part of the aperture 24 and/or the cover or lens 25. In particular, the reset device 1 may cover the field of view or a part of the field of view of the sensor 2.

The reset device 1 may include a shutter 11 located with respect to a reset device aperture 12. The reset device aperture 12 is located with respect to the housing 10 of the reset device 1 such that, when the reset device 1 is secured to the sensor 2, light passing through the reset device aperture 12 will reach the sensor element 12 (and, in some embodiments, substantially all of the light which reaches the sensor element 12 may have had to pass through the reset device aperture 12). In other words, the field of view of the sensor 2 may be through the reset device aperture 12 in some embodiments (when the reset device 1 is secured to the sensor 2). The reset device aperture 12 may be at least partial defined by the housing 10.

In embodiments in which the reset device 1 is part of the sensor 2 then the arrangement may be generally the same - i.e. the reset device aperture 12 is positioned such that light passes therethrough to reach the sensor element 22.

The shutter 11 may be configured to be actuated between an open configuration and a closed configuration in relation to the reset device aperture 12. In the open configuration, the shutter 11 may permit the transmission of light (e.g. infrared light) through the reset device aperture 12 (and to the sensor element 22, if the reset device 1 is secured to the sensor 2 or is a part thereof). In the closed configuration, the shutter 11 may inhibit or block a significant amount of light from transmission through the reset device aperture 12 (and to the sensor element 22 when the reset device 1 is secured to the sensor 2 or is a part thereof). In some such embodiments a significant amount of light may be substantially all of the light (or substantially all of the infrared light). In some such embodiments a significant amount of light may not be a substantial amount of the light (e.g. infrared light) which would otherwise pass through the reset device aperture 12 (i.e. which would otherwise reach the sensor element 22). In some embodiments, the significant amount of light may be a portion of the light which is otherwise transmittable through the shutter 11 when it is in the open configuration.

In some embodiments, the housing 11 may be generally annular and the reset device aperture 12 may be generally centrally located therethrough - although other configurations are also possible.

The shutter 11 could take a number of different forms. The shutter 11 may be, for example, a liquid crystal device (as shown in figure 10, for example) which can be electrically controlled between the open and closed configurations. A liquid crystal device is an example of a shutter device which has a tuneable opacity and other such devices could be used.

The shutter 11 may be a mechanical device such as a rotatable and/or oscillating member which is configured to move between the open and closed configurations due to movement with respect to the reset device aperture 12.

In embodiments in which the shutter 11 is a mechanical device, then the operation of the shutter 11 may still be electrically driven. For example, the shutter 11 may include one or more mechanical shutter elements 111 (see figures 6-9, for example).

The shutter 11 may, for example, be a leaf shutter or a diaphragm shutter.

In some embodiments, the shutter 11 may include a disc with one or more apertures defined therethrough such that rotation and/or oscillation of the disc causes the movement of the shutter 11 between the open and closed configurations with respect to the reset device aperture 12 and/or the sensor element 22 (see figure 9, for example). The disc may be configured to rotate in a single direction or may be configured to rotate in a reciprocal manner (i.e. oscillating between movement in one rotational direction and another). In some embodiments, the or each mechanical shutter element 111 may move in a linear reciprocal manner (i.e. moving in a first linear direction and then a second linear direction repeatedly with respect to the reset device aperture 12).

Another example of a shutter 11 is shown in figures 6-8, which depict a shutter 11 with a plurality of mechanical shutter elements 111 which are configured to iris open and closed.

The shutter 11 may, therefore, be driven by a driving circuit 13 (see figure 11, for example) of the reset device 1 which may be located in the housing 10. The driving circuit 13 may be configured to drive operation of the shutter 11 between the open and closed configurations.

In some embodiments, the driving circuit 13 may include a motor (or other electromechanical driving device) which is coupled, for example, to the shutter 11 and is configured to drive the shutter 11 between the open and closed configurations (which may include the driving of movement of the or each mechanical shutter element 111). In some embodiments, the driving circuit 13 may include one or more components configured to drive a shutter 11 in the form of a liquid crystal device (or other device with tuneable opacity) between the open and closed configurations.

The driving circuit 13 may, therefore, be communicatively coupled to the shutter 11.

The driving circuit 13 may operate under the control of a controller 14 (see figure 11 for example) which may be located in the housing 10. The controller 14 may include a microcontroller or other processing device, which may be communicatively coupled to the driving circuit 13 and configured to cause the operation thereof to drive the shutter 11.

The reset device 1 may include a power source 15 (see figure 11, for example) which is configured to power the components of the reset device 1. The power source 15 may be configured to provide electrical power to one or more of the shutter 11, the driving circuit 13, and the controller 14.

The power source 15 may include a battery which is configured to store electrical power. In some embodiments, the power source 15 includes a power scavenging device (such as a solar panel) which is configured to scavenge power from the local environment - e.g. light - and to use this power to operate the reset device 1 and/or to recharge the battery of the power source 15 (if provided). In some embodiments, the power source 15 may include a capacitor as an energy storage device to store energy for use in powering the shutter 11, the driving circuit 13, and/or the controller 14 - e.g. instead of or in addition to the battery.

In some embodiments, the power source 15 may be a coupling to a mains power supply, for example, and this may be a coupling to a power supply for the sensor 2.

In some embodiments, the reset device 1 may include a receiver 16 (see figure 11, for example). The receiver 16 may be configured to receive, for example, a radio signal providing instructions which may be used by the controller 14 to operate the reset device 1. Accordingly, the receiver 16 may be communicatively coupled to the receiver 16.

The instructions may include, for example, an instruction to determine when actuation of the shutter 11 should occur and/or the frequency of operation of the shutter 11.

In some embodiments, the reset device 1 may be provided with a transceiver 17 (see figure 1, for example). The transceiver 17 may be configured to perform the operations of the receiver 16 and, in addition, to transmit one or more signals indicating or confirming at least one aspect of the operation of the reset device 1. The at least one aspect may include the current operational state of the shutter 1, the current frequency of operation of the shutter 1, the current power level or voltage level of the power source 15, for example.

The transceiver 17 and receiver 16 may be configured to communicate with, for example, a smart home hub 18 (see figure 12, for example) which may be, in turn, configured to control and/or communicate with one or more other smart home devices. In some embodiments, the transceiver 17 and receiver 16 may be configured to communicate with a mobile telephone or other computing device 19 (via the smart home hub 18 or otherwise). The computer device 19 may be configured to execute a configuration program to permit a user to enter one or more operating parameters for transmission to the reset device 1 and/or to receive one or more operating parameters from the reset device 1 for display to the user via the computing device 19.

In some embodiments, the transceiver 17 and receiver 16 may be configured to communicate with a digital assistant device which may be configured to receive audible commands from a user. This may enable the user to configure the reset device 1 through verbal commands, for example, by the digital assistant device converting the commands for transmission to the reset device 1 via the receiver 16 or transceiver 17.

As will be appreciated, therefore, the controller 14 may be a programmable controller.

The programming of the controller 14 may be achieved remotely, for example.

In some embodiments, one or more user actuatable controls (such as buttons and/or dials) may be provided as part of the reset device 1 to allow the user to program the controller 14 and/or to adjust one or more parameters used by the controller 14 in controlling the operation of the shutter 11 or some other aspect of the reset device 1 (such as the operation of the power source 15).

In operation, therefore, the reset device 1 may be used to control the amount of light (e.g. infrared light) which reaches the sensor element 22. By repeated reduction in the amount of light (e.g. infrared light) which the sensor element 22 receives, using the shutter 11, the sensor 2 effectively reset with each repeated reduction. Therefore, the sensor 2 is more sensitive to movements within its field of view (e.g. movements of an infrared emitting object). As a result a stationary person, for example, within the field of view of the sensor 2 will be less likely to be viewed as background (i.e. part of a background thermal image) by the sensor 2.

In some embodiments, the shutter 11 in the closed configuration may substantially absorb or reflect the impinging light (e.g. infrared light).

In some instances, complete or substantial blocking of light (e.g. infrared light) by the shutter 11 in the closed configuration from the sensor element 22 is not required. Instead, the contrast between the light which reaches the sensor element 22 when the shutter 11 is in the open configuration and when the shutter element 22 is in the closed configuration may be sufficient to achieve the desired effect.

As will be appreciated, the sensor 2 may be used to control the operation of lights and/or heating. The sensor 2 may be a ceiling mounted sensor 2 and so the reset device 1 may also be ceiling mounted.

Some embodiments of the present invention seek to reduce overall power consumption by ensuring that one or more devices controlled by the sensor 2 do not needlessly perform power-down operations and power-up operations. As will also be appreciated, the power scavenging used by some embodiments may be particularly advantageous.

The frequency of operation of the shutter 11 may depend on the nature of the sensor 2 the desired effect, and the environment in which the sensor 2 is located.

When used in this specification and claims, the terms comprises and comprising and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A reset device for resetting a passive infrared sensor, the device comprising:

a housing at least partially defining a reset device aperture; and a shutter mounted with respect to the reset device aperture and operable between a closed and an open configuration, wherein the housing is configured to be mounted with respect to a sensor element of a passive infrared sensor such that operation of the shutter between the open and closed configurations alters the mount of infrared light transmittable through the reset device aperture to the sensor element.

2. A reset device according to claim 1, further comprising:

a controller configured to operate the shutter between the open and closed configurations at a predetermined frequency.

3. A reset device according to any preceding claim, wherein the shutter includes a device with a tuneable opacity.

4. A reset device according to claim 1 or 2, wherein the shutter includes a mechanical device.

5. A reset device according to claim 4, wherein the mechanical device includes a rotating or oscillating member.

6. A reset device according to any preceding claim, further including a power source which is configured to scavenge power from the environment.

7. A reset device according to any preceding claim, further including a receiver or transceiver configured to receive one or more instructions to control an aspect of the operation of the shutter.

8. A passive infrared sensor in combination with a reset device according to any preceding claim.