MONITORING DEVICE AND SYSTEM
The present invention relates to a device and system for monitoring the occurrence of condensation on a surface. More particularly, the present invention relates to a dew point and temperature sensing device and system which is particularly suited for monitoring condensation on crops. The invention extends to a corresponding kit of parts and method.
Condensation has a detrimental effect on a wide variety of industrial processes which are sensitive to the presence of dew or other moisture. In particular, in agriculture, condensation on the surface of a crop promotes the germination of fungal spores and mildew. This can damage the crop or cause it to become unfit for consumption. This is a particular problem for greenhouses, where temperature and humidity may be relatively high.
A variety of solutions have been proposed to monitor humidity and/or temperature so as to allow conditions to be controlled to prevent condensation occurring. However, such solutions may be limited in that they may not be able to monitor humidity and/or temperature at the most appropriate location. Furthermore, the utility of data from such monitoring solutions may be limited by the limited interoperability of such monitoring solutions.
Aspects and embodiments of the present invention are set out in the appended claims. These and other aspects and embodiments of the invention are also described herein.
According to at least one aspect described herein, there is provided a device for monitoring the occurrence of condensation on a surface (and/or, optionally, on or in an object), comprising: a body comprising a processor; a humidity sensor provided in communication with the processor; a temperature sensor provided in communication with the processor; and an arm extending from the body and being movable relative to the body; wherein the arm is operable to support the temperature sensor proximate a monitored surface (and/or optionally a monitored object).
The arm may comprise a plurality of rigid links, each link being movable relative to the adjacent links. The plurality of rigid links may be connected via ball joints. The ball joints may be sufficiently stiff to maintain the position of each link relative to the adjacent links. The temperature sensor may be mounted at a distal end of the arm, optionally where the arm comprises an internal conduit for retaining wires for connecting the temperature sensor to the processor.
Optionally, the humidity sensor is external to the body. The humidity sensor may be mounted on a further arm extending from the body and being movable relative to the body, wherein the further arm is operable to support the humidity sensor adjacent a monitored surface (and/or optionally a monitored object).
The device optionally further comprises means for transmitting sensor data from the device and/or means for communicating with one or more further such devices.
The humidity sensor may be a combined humidity and temperature sensor, optionally a capacitive sensor. The combined humidity and temperature sensor may be configured to operate continually, and the device may be configured to measure the temperature of the monitored surface (and/or optionally the monitored object) continually.
The temperature sensor may be an infrared temperature sensor. Optionally, the device further comprises a further temperature sensor.
The device may comprise a sensor hut surrounding the humidity sensor. The sensor hut may comprise a Stevenson screen, and in use may depend downwardly from the device (under gravity). The downward dependence of the sensor hut may allow the Stevenson screen to be reliably positioned to protect the humidity sensor. The downward dependence of the sensor hut may also allow the humidity sensor to be located remote to a monitored surface (since the arm may extend non-downwardly, e.g. horizontally, to support the temperature sensor proximate the monitored surface). The humidity sensor may be removably connected to the device.
Optionally, the device further comprises a clamp for attaching the device to an object.
According to at least one aspect described herein, there is provided a kit of parts, comprising: a device for monitoring the temperature of a surface (and/or optionally an object), comprising: a body comprising a processor; a temperature sensor provided in communication with the processor; and an arm extending from the body and being movable relative to the body, wherein the arm is operable to support the temperature sensor proximate a monitored surface (and/or optionally a monitored object), and a humidity sensor; wherein the humidity sensor is operable to communicate with the processor of the device thereby to form a device for monitoring the occurrence of condensation on a surface (and/or optionally an object).
According to at least one aspect described herein, there is provided a system for monitoring the occurrence of condensation on at least one surface (and/or, optionally, on or in an monitored object), comprising: at least one device as described herein, wherein the at least one device is arranged to monitor at least one surface (and/or optionally at least one object); and a server provided in communication with the at least one device.
The server may be arranged to compute a dew point temperature based on a temperature and a humidity measured by the at least one device; optionally, for each of the at least one device. The server may be arranged to compare a dew point temperature against a temperature of the at least one monitored surface (and/or optionally the at least one monitored object) thereby to monitor the occurrence of condensation on the at least one monitored surface. Optionally, the temperature of the at least one monitored surface (and/or optionally the at least one monitored object) is not used in calculating the dew point temperature.
The system may further comprise a user device for displaying data related to the occurrence of condensation on at least one surface (and/or optionally on or in at least one object). The user device may be operable to receive alerts from at least one device in dependence of a monitored parameter exceeding a predetermined threshold.
The system optionally comprises a plurality of devices arranged to communicate with each other. The plurality of devices may be arranged as a mesh network. The system optionally further comprises one or more gateway devices for interfacing between the mesh network and the server. The system optionally further comprises one or more routers in communication with the one or more devices for improving the performance of the mesh network. According to at least one aspect described herein, there is provided a method of monitoring the occurrence of condensation on a surface (and/or optionally an object) using the device and/or the system as described herein, comprising: continually monitoring the temperature at a surface (and/or optionally the an object); and continually monitoring the dew point temperature.
The invention extends to methods, system and apparatus substantially as herein described and/or as illustrated with reference to the accompanying figures.
The invention also provides a computer program or a computer program product for carrying out any of the methods described herein, and/or for embodying any of the apparatus features described herein, and a computer readable medium having stored thereon a program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein. The invention also provides a signal embodying a computer program or a computer program product for carrying out any of the methods described herein, and/or for embodying any of the apparatus features described herein, a method of transmitting such a signal, and a computer product having an operating system which supports a computer program for carrying out the methods described herein and/or for embodying any of the apparatus features described herein.
Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory.
Furthermore, features implemented in hardware may generally be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly.
As used herein, the term 'dew point' preferably connotes the temperature below which air is saturated with water vapour and the water vapour undergoes condensation (e.g., on a surface). The term 'dew point' is preferably synonymous with the term 'dew point temperature'. As used herein, the term 'humidity' preferably connotes a measure of the amount of water vapour present in air (air comprising water vapour and other gases). Preferably, the term 'humidity' refers to relative humidity, but can also refer to absolute humidity or specific humidity. The relative humidity of air at a given temperature is the ratio of the partial pressure of water vapour in the air to the equilibrium vapour pressure of water at that temperature. The partial pressure of water vapour in a given volume of air is the pressure that the water vapour present in the given volume would have if it alone occupied the entirety of the given volume. The equilibrium vapour pressure of water at a given temperature is the pressure exhibited by water vapour at a liquid-gas interface at that temperature. Relative humidity is preferably expressed as a percentage. A relative humidity of 100% in air signifies that the air is saturated with water vapour.
As used herein, the term 'proximate' preferably connotes 'near' or 'next to'; more preferably 'immediately next to'; yet more preferably 'at a certain distance from a surface such that readings taken using a sensor relate substantially to properties of the surface alone'. Preferably, the term 'proximate' excludes the connotation of 'in contact with'.
As used herein, the term 'target surface' should preferably be understood to be synonymous with the term 'monitored surface'.
It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently.
The invention will now be described, purely by way of example, with reference to the accompanying drawings, in which:
Figure 1 a shows a perspective view of an example embodiment of a device for monitoring the occurrence of condensation on a surface;
Figure 1 b shows a further perspective view of the device of Figure 1a in an alternative configuration;
Figure 1 c shows a side view of the device of Figure 1a;
Figure 1d shows an underside view of the device of Figure 1a;
Figure 2 shows devices in use in an agricultural setting; Figure 3 is a schematic diagram showing a system made up of a plurality of devices; Figure 4 shows an example page of a user interface of a user device, showing representative sensor data outputted from a device; and
Figure 5 shows a further example page 500 of the user interface of the user device.
Specific Description
Figure 1 a shows a perspective view of a device 100 for monitoring the occurrence of condensation on a surface. The monitoring device 100 comprises a body 1 1 1 , which is generally cuboid in shape (although it will be appreciated that other shapes are of course possible). The body 1 1 1 contains a processor for processing information received from a plurality of sensors provided in communication with the body (as will be detailed later on), as well as an internal battery (specifically, a 3.0 - 4.2 V power supply) for powering the device 100. The processor is also in communication with an internal transceiver (not shown) for sending and receiving data. The body is formed of two hollow sections 1 11 a and 1 1 1 b, which are fitted together via screws. This allows the interior of the body 1 11 to be securely enclosed and protected while allowing convenient access for maintenance. A seal is provided in between the sections 1 11 a, 11 1 b to mitigate the ingress of moisture and/or dust into the body 1 1 1. The body includes an aperture 113 (optionally, sealed by a cap) for charging the internal battery and for providing a data connection to allow for a wired connection with the processor.
The device 100 further comprises a clamp 102 which is attached to the body 1 1 1. The clamp 102 is a single component, which includes a support 104 which extends across a major surface of the body and is connected to the body 1 1 1 via screws, preferably via the same screw connections that fasten the two sections 1 1 1 a, 1 11 b of the body together. The use of a support 104 which extends all the way across the body 1 11 may serve to securely connect the clamp 102 to the body 1 1 1. The clamp 102 further comprises a jaw 106 extending away from the support 104 (and from a side of the body 1 1 1 ), a rod 109 (not visible in Figures 1 a and 1 b) for engaging with the jaw 106, and a knob 108 for moving the rod 109 relative to the jaw 106, thereby to open or close the clamp 102. The clamp 102 is arranged to be especially suitable for clamping to a rod or dowel of around 6 - 10 mm in diameter. The device 100 further comprises an arm 1 10 which extends out of a side of the body 1 1 1 , the arm having a proximal end 1 10a in connection with the body 1 1 1 , and a free distal end 1 10b. The arm 1 10 comprises a plurality of rigid links 1 12, which are successively connected in a chain. Each rigid link 1 12 comprises a ball joint end 114a and a socket end 1 14b; the socket end of each rigid link being arranged to receive the ball joint of a further rigid link, thereby mating with the further rigid link. Two rigid links thereby connected via such a ball and socket connection are movable relative to each other via the ball joint of one link rotating in the socket of the second link, which allows adjacent links to rotate relative to each other throughout a wide range of motion. As such, the chain of links that form the arm 1 12 is movable relative to the body 1 11 and can adopt a wide variety of positions relative to the body.
Importantly, the ball and socket joint formed by adjacent links is relatively stiff, such that absent an external force the adjacent links 1 12 do not slip relative to each other. The stiffness of the links is sufficient such that links towards the proximal end 110a of the arm 1 10 do not slip relative to each other under the weight of the remainder of the arm. This allows the arm to be set in a particular position (for example by being manually positioned by a user) which is then maintained by the arm. By way of illustration, Figure 1 b shows the device 100 of Figure 1 a where the arm 1 10 is shown in a different position. In Figure 1 b, the arm 1 10 is shown extending substantially downwardly from the body of the device 1 1 1 , whereas in Figure 1 a, the arm extends substantially laterally away from the body 1 1 1 of the device. All other elements of the device in Figure 1 b are the same as those in Figure 1a.
The arm 1 10 also has a modular nature, in that links 1 12 may be added or removed to extend or shorten the arm as a whole. This may allow the arm to be further adapted for particular use cases. The arm 1 10 comprises a temperature sensor 1 18, which is located at the distal end 1 10b of the arm. The temperature sensor is enclosed within a housing 116 formed of cast epoxy, which is connected to a distal link 1 12 of the arm via a cast joint. The housing 1 16 includes an aperture (i.e. an open end) at the distal end 1 10b of the arm to allow the temperature sensor to receive data from any object that the aperture (and the arm as a whole) is pointed towards. The temperature sensor 1 18 is an infrared temperature sensor, which has a measurement range of approximately -40 degrees Celsius to 85 degrees Celsius for sensor temperature and -70 degrees Celsius to 380 degrees Celsius for object (i.e. target) temperature, or at least a substantial portion of these ranges. The temperature sensor 1 18 has a field of view of around 10 degrees (measured from a central axis of the aperture of the housing 1 16), which is defined by the form of the sensor itself. This may improve the temperature sensor's ability to measure the temperature of specific objects, rather than the environment as a whole. The temperature sensor is selected so as measure temperature accurately to within approximately +/-0.5 degrees Celsius under typical operating conditions (for example between 0 degrees Celsius and 50 degrees Celsius for either/both of sensor temperature and object temperature). It will of course be appreciated that other temperature sensors (having a range of specifications) may be used in place of the described temperature sensor 1 18.
The temperature sensor 1 18 is powered by the internal battery of the device, and so is provided in wired communication with the battery. The temperature sensor is arranged to provide temperature measurements to the processor in the body 1 1 1 via a wired connection. The power connection to the battery and the connection to the processor is effected by wires which extend through the interior of the arm 1 10, from the distal end 1 10b to the body 1 1 1. In this regard, the chain of rigid links 1 12 forming the arm 1 10 have holes bored centrally down their longitudinal axes such that a hollow conduit is formed for supporting the wires. Alternatively, the temperature sensor 118 may transmit wirelessly to the processor.
The device 100 further comprises a humidity sensor 126 (specifically, a combined temperature and humidity sensor, referred to as a temperature/humidity sensor 126 - not shown in Figures 1 a and 1 b), which is disposed within a 'sensor hut' 122 and connected to the body 1 1 1 via a wire 124 (such as a 5 V cable), which extends from the body 1 1 1 to the temperature/humidity sensor 126. The wire 124 powers the temperature/humidity sensor 126 (where the sensor has a supply voltage of 2.8 V) and transmits data from the sensor 126 to the processor. The wire 124 extends out of the same side of the body 11 1 to the arm 110. Figure 1 c is a side view of the device 100 (where the arm 1 10 is shown in the same position as in Figure 1 a). The sensor hut 122 is a generally cylindrical container (although other shapes are of course possible) with one open end (the distal end in relation to the body 1 1 1 ). The sensor hut comprises a plurality of sections 122a which are arranged on top of each other, wherein apertures 122b (or 'louvres') are defined between the sections 122a in the same way as a 'Stevenson screen'. More specifically, each section 122a has angled side walls such at least part of each section forms the shape of a truncated cone, where the apertures 122b are defined between each section 122b as a result of the different diameters of each part of the section. In use, the apertures 122b provide ventilation for the temperature/humidity sensor 126. The angled side walls mean that condensation (if it occurs) runs off the sensor hut 122.
Figure 1 d is an underside view of the device 100 (where the arm 1 10 is shown in the same position as in Figure 1a). The temperature/humidity sensor 126 is arranged on an inner side wall of the sensor hut 122, such that the temperature/humidity sensor 126 is close to a central axis of the sensor hut 122.
The sensor hut 122 prevents sunlight from interfering with the operation of the temperature/humidity sensor 126 and allows for airflow around the sensor, which may improve the accuracy of measurement (in particular when the temperature/humidity sensor 126 is placed in direct sunlight). The sensor hut 122 also serves to protect the temperature/humidity sensor 126 from damage in use.
The temperature/humidity sensor 126 is a capacitive sensor, which has a temperature measurement range of approximately -20 degrees Celsius to 125 degrees Celsius, or at least a substantial portion of that range, and a humidity measurement range of approximately 0 to 100% relative humidity, or at least a substantial portion of that range. The temperature/humidity sensor 126 is selected so as measure temperature accurately to within approximately +/-0.2 degrees Celsius and humidity to within +/-1.8% under typical operating conditions. The temperature/humidity sensor 126 communicates with the processor via a protocol such as a 'two-wire interface' bus.
In use, measurements of temperature and relative humidity taken using the temperature/humidity sensor 126 are communicated by the processor (using the transceiver) to a server 320 (not shown in Figure 1 a and 1 b), which calculates (or at least approximate to a relatively high degree of accuracy) a dew point temperature of the environment surrounding the device 100. A variety of methods can be used to calculate the dew point temperature - in an example, the Magnus formula is used: c x γ(Τ, RH)
DP = — - b - γ(Τ, RH)
where
RH
Y(T, RH)≡ ln (—) and T is measured temperature (in degrees Celsius), DP is the dew point temperature (in degrees Celsius), RH is relative humidity (expressed as a percentage), and b and c are tabulated constants, of which there are several sets in use. Example values are 6=18.678 and c=257.14 degrees Celsius. Various other calculations and/or approximations may be used in order to produce an accurate dew point reading. Using a combined temperature/humidity sensor may allow for more accurate calculation of the dew point temperature due to improved consistency (and calibration) between the temperature and humidity readings, due to the fact that they are taken at the same location and by the same sensor. Using a combined humidity/temperature sensor 126 that is separate from the temperature sensor 1 18 may allow a temperature reading to be taken remote (though still nearby) from the plant, where this temperature differs from the temperature at the plant itself - this may allow the calculation of a dew point temperature that is not dependent on the temperature at the plant, improving the accuracy of dew point calculation as a whole.
It will be appreciated that, in an alternative, temperature readings from the temperature sensor 1 18, rather than from the temperature/humidity sensor 126, could also be used in calculating the dew point temperature.
The processor is arranged to sample readings from both the temperature sensor 1 18 and the temperature/humidity sensor 126 with a relatively high sample rate (such as once per minute), such that near real time data is acquired by the processor and communicated to the server 320.
Figure 2 shows devices 100 in use in an agricultural setting. The device 100 is arranged for monitoring the occurrence of condensation (to allow condensation to be prevented) on a particular (target) surface, such as the surface of a crop 202 in a greenhouse (or other growing environment), by fixedly locating the device 100 near the particular surface. For example, where the target surface is a surface of a crop growing on a vine of a plant, the device 100 may be fixed on an object that does not move relative to the crop/plant, such as a rack 204 supporting the plant (as shown in Figure 2) or a nearby shelf or bench. The clamp 102 may be used to assist with holding the device 100 in place. The arm 1 10 may then be positioned so as to locate and support the temperature sensor 1 18 (at the distal end 1 10b of the arm 1 10) proximate the target surface (i.e. immediately next to and close to the target surface, although not in contact with the target surface), such that the target object is within range and within the field of view of the temperature sensor 1 18. This allows an accurate temperature reading to be taken of the surface itself, rather than the surrounding environment.
It will be appreciated that in many situations the temperature sensor 1 18 could not have been placed proximate the target surface (of a crop 202) without the use of the flexible arm 1 10, due to the dearth of effective mounting locations next to the plant which would allow the temperature sensor 1 18 to monitor a particular surface. Although sensors could be mounted on the plant itself, this is generally not desirable as this may weigh down the plant and affect growth. The use of the arm 1 10 also allows the sensor to be dynamically repositioned by a user if necessary, for example in accordance with the growth of the plant.
The sensor hut 122 (not visible in Figure 2) containing the temperature/humidity sensor 126 may be mounted next to the device, but preferably extends generally towards the monitored surface (for example, where the device 100 is mounted above the monitored surface, the sensor hut 122 depends generally downwards by hanging from the wire 124). The sensor hut 122 may be fastened to a particular object, such as the plant, to keep it in position. The sensor hut 122 is arranged to be vertical in use (so as to protect the temperature/humidity sensor 126). Generally, it is beneficial for the sensor hut 122 to be as close to the target surface as possible - however, acceptable results can be obtained if the sensor hut 122 is generally in the vicinity of the target surface, or even if the sensor hut 122 is located some distance away from the target surface. This is because the disparity between the dew point temperature at the monitored surface and in the surrounding environment is not as vast as the disparity between the measured temperature on the monitored surface and in the surrounding environment (as the relative humidity at the target surface does not generally differ substantially from the relative humidity in the surrounding environment).
The actual temperature 206 of the monitored surface and the dew point temperature 208 are shown in Figure 2. The dew point temperature 208 (calculated based on the temperature/humidity sensor 126) is calculated by the server as described and compared against the monitored temperature at the target surface. If the monitored temperature 206 is equal (or very close to) the dew point temperature 208, this indicates that condensation has occurred (or will imminently occur) on the target surface. In the described use-case of crops in a greenhouse, this is problematic as condensation promotes the germination of fungal spores and mildew, which can affect whether the crop is fit for human consumption. The device 100 allows the temperature 206 of the monitored surface to be compared against the dew point temperature 208, allowing remedial action to be taken if the monitored temperature 206 approaches the dew point temperature 208.
Importantly, the temperature 206 at the target surface is generally lower (i.e. closer to the dew point temperature 208) than the environmental temperature - thus, measuring the temperature at the target surface (by supporting the temperature sensor 118 proximate the monitored surface) allows for improved accuracy in monitoring condensation (or the likelihood of condensation occurring) on the target surface. Furthermore, since the surface of a crop 202 may be expected to be one of the coldest surfaces in a greenhouse, condensation may occur initially on these surfaces (i.e. before many other surfaces, apart from metal surfaces on the interior of a greenhouse in which the device 100 is used).
It will be appreciated that the fact that the device 100 can measure three parameters - surface temperature, ambient temperature, and ambient humidity - at a target may provide improved accuracy over solutions which simply measure environmental temperature and humidity at one central location.
Figure 3 shows a system 300 made up of a plurality of devices 100. Each device 100 is arranged to monitor a separate target surface on different crops 202 (although it will be appreciated that the devices 100 could of course monitor different surfaces on the same crop 202). For visibility, the temperature sensor 1 18 and the temperature/humidity sensor 126 are shown separately from the device 100. As will be appreciated, the fact that each device 100 monitors separate crops means that that the temperature at each plant is measured separately, and the dew point temperature in the vicinity of each crop is measured separately via the temperature/humidity sensor 126 (rather than, e.g., the dew point temperature over a wider area or in respect of multiple plants being measured). This may improve accuracy.
As shown by the connections between each device 100, all of the devices 100 are arranged to all communicate with each other and additionally with a gateway node 310. This network topology is referred to as a private mesh network. The gateway node 310 is arranged to link the mesh network (which is based on a Low Power Wide Area Network (LPWAN) protocol) to the internet, for example via Wi-Fi. Using a protocol such as LPWAN in the mesh network is generally desirable to improve the battery life of the devices 100.
The gateway node 310 allows data connected by the devices 100 in the system 300 to be exported to the internet, in particular to a cloud server 320 (i.e. the previously mentioned server 320, which is external to the device). The cloud server 320 is arranged to calculate a dew point temperature 208 and compare it against the temperature 206 at the target surface, as described. The data stored in the cloud server 320 may be accessed by a user device 330 (such as a smartphone, or a desktop, tablet or laptop computer). A variety of user devices 330 may be used to interface with the cloud server 320 using a web interface or a specialised software application. Other systems may be able to access the content of the cloud server 320 via an API.
The system 300 may further comprise one or more routers (not shown) for the mesh network, which are provided in communication with one or more devices 100 and act to control the mesh network. In use, the devices 100 are generally in a low power mode and are configured to 'wake' only when action is required (for example, when temperature or humidity is sampled). The wake time is configured to be as short as possible in order to keep the battery life of the devices 100 as long as possible. As such, separate routers may be used with the mesh network to allow the network to cover a wider area. The use of a mesh network may improve the resilience of the network to disruption (since if one node fails, the other nodes compensate) and thereby the reliability of the network as a whole. Any outages in the network may correspond with the monitored temperature 206 approaching the dew point temperature 208, so reliability is an important concern. The use of a mesh network also means that the network is strengthened as the number of nodes is increased.
Figure 4 shows an example page 400 of a user interface of the user device 330, showing representative sensor data outputted from a device 100. Data related to the temperature 206 at the target surface, the dew point temperature 208, and (optionally) measured humidity 210 is continually measured/computed and is output from the device 100 in near real time, and so may be displayed on a graph as a function of time.
Viewing the data as a graph allows a user to compare trends over time. In the data illustrated in Figure 3, a period of increased humidity from approximately Aug 24 20:00 onwards is concomitant with the temperature 206 at the target surface being closer to the dew point temperature 208 and thus there being a more imminent risk of occurrence of condensation on the monitored surface. (In general a higher humidity means that the temperature 208 is closer to the dew point temperature 208, and thus that there is a more imminent risk of condensation.)
Alternatively, the device 100 or system 300 can be configured to compute the temperature 206 at the target surface, dew point temperature 208, and/or humidity 210 at a desired frequency and/or during a desired time interval, in which case the user device can display the data over the desired time interval. The user interface can be used to begin, pause, and end measurement intervals, and display the corresponding data from those measurement intervals. The user interface can also be used to view data from several devices 100, optionally concurrently. The user interface may also be used to set up and monitor the status of the mesh network - for example, the user interface may be used to register and add new devices to the network.
Figure 5 is a further example page 500 of the user interface of the user device 330. The user interface also allows the users to set up alerts in dependence on one or more specific parameters being satisfied, such a monitored parameter exceeding a predetermined threshold. The page 500 comprises several fields to be completed in order to configure the alert. In a 'Selected sensor' field 502, the user can specify a particular monitoring device 100 belonging to the system 300 on the basis of the data from which they wish to receive an alert (here the user has specified a device called 'Dew point sensor'; there may be a plurality of devices to choose from, for example, 'Dew point sensor (1 ,2,3,...)', belonging to the system or network of devices picture in Figure 2, for example).
In a 'Description' field 504, the user can input a desired description or name for the alert, for the user's information purposes when the alert is sent by the device (and received by the user). In a 'Send notification when' field, the user can input the criterion to be met in order for the alert to be triggered and sent (by selecting options from the drop-down boxes or manually specifying a value). As shown in Figure 5, the user has specified that an alert should be triggered when the temperature is within 2 degrees Celsius of the dew point temperature. Each element of the criterion can be modified either by using the drop-down boxes (for example, in the left and middle fields of 506) or by manually specifying a value (for example, in the right field of 506). For example, the criterion for sending an alert could be modified in this way to be 'Humidity equal to 75%' or 'Temperature within 10°C of dew point temperature'. It is possible to specify further criteria to be met for the alert to be triggered with an 'Add condition' button 508.
In a field 510, the user can specify the length of time for which the desired criterion must be met before triggering the alert. For example, it might be the case that if the temperature comes within 2 degrees Celsius of the dew point temperature only for a brief period of time (one minute, say), it is relatively benign as far as risk to the monitored crop 202 is concerned, and no alert should be triggered; but it might be the case that if the temperature remains within 2 degrees Celsius of the dew point temperature for a more extended length of time (5 minutes, say), it is more pathological and an alert should be triggered and sent to the user. As shown in Figure 5, the user has specified that the specified criterion should be met for 120 seconds (i.e., 2 minutes) before the alert is triggered and sent. Once the user has specified the sensor on whose data the alert should be based; a description or name for the alert; an alert criterion; and a length of time that criterion should be met for before the alert is triggered and sent, a 'Create' button 512 can be used to create the alert. Alternatives and Extensions
Although the device 100 and system 300 have principally been described with reference to use in agriculture, it will be appreciated that a variety of alternative usages are possible - in particular, for any process in which the occurrence of condensation and/or dew point temperature is important, such as certain industrial forming processes, in food manufacture, or in plumbing.
Optionally, the sensor hut 122 comprises external fixings to assist in it being attached in place, such as holes through which cable ties can be attached.
Although the device 100 has principally been described with reference to monitoring the temperature of an external surface (of a crop), it may instead or additionally be arranged to monitor an interior surface (of a crop). This is particularly important for crops having an internal void, such as bell peppers, where condensation may occur on an interior surface. In one example, the temperature sensor 1 18 comprises two sensors, one configured to measure the temperature of an external monitored surface and another configured to measure the temperature of an internal monitored surface (or simply an internal temperature of an object having the external surface).
In an alternative, the dew point temperature 208 (and/or other calculated parameters) is calculated on the device 100 (by the processor), rather than at the cloud server 320. In this case, the device 100 may be arranged to communicate only the raw temperature sensor 1 18 readings and the calculated dew point temperature (and not the raw temperature/humidity sensor readings) to the other devices 100 and the gateway node 302 in the system 300.
Optionally, the device 100 themselves act as routers within the system 300, in place of or in addition to the described routers.
Optionally, any of the sensors and associated components (such as the temperature/humidity sensor 126, sensor hut 122, and wire 124; or alternatively/additionally the arm 1 10 and temperature sensor 1 18) are removable from the body 1 1 1 , and may be replaced as necessary. Optionally, such components may be retrofitted to an existing sensor including the body 1 11. In an alternative, the temperature/humidity sensor 126 is provided on a further flexible arm in the same way that the temperature sensor 1 18 is provided on the described arm 1 10. The sensor hut 122 holding the temperature/humidity sensor 126 may be positioned on a distal end of the arm 1 10 so as to allow the sensor hut 122 to protect the temperature/humidity sensor 126 (when located in vertical position), as described.
In an alternative, a single temperature/humidity sensor is used on the arm 1 10 in place of the temperature sensor 1 18. The measured temperature may then be used in both the dew point temperature 208 calculation and as the measured temperature 206 of the target surface. In such an embodiment, the described sensor hut 122 including the temperature/humidity sensor 126 may not be necessary.
Optionally, the temperature/humidity sensor 126 may be internal to the body 1 1 1. This may be useful for applications where the device is not exposed to direct sunlight.
In an alternative, different sensors (optionally, for sensing different parameters) may be used in place of the described temperature sensor 1 18 and temperature/humidity sensor 126.
It will be understood that the invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.
Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.
Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.