Field of Invention The invention relates to improved apparatus and methods for detection of an electric fence. More particularly, the invention relates to apparatus and methods for contactless detection of an electric fence.

Background of the Invention

The use of electric fencing is widespread, especially on farms for animal control. Other applications are typically for security, for example home security, prisons, and military areas. Electric fencing is commonplace in both permanent and temporary installations. One common type of electric fencing, especially used on farms, is constructed from one or more wires mounted to posts via an insulating material, and connected to an energiser. The energiser periodically charges the wire(s) with a pulse, for example once every second or a similar frequency. If a grounded animal or person makes contact with the wire(s) at the same time that the energiser charges the wire, a circuit is completed between the wire and the ground, through the animal or person. The sensation caused by the resulting flow of current through the animal or person is typically unpleasant to such an extent that the animal or person is not harmed, yet will be deterred from making contact with the wire(s) again, or at least soon learn not to do so.

An electric fence wire used for the control of animals on farm is often a simple steel wire or a woven rope-like material with fine conducting wires.

One drawback with electric fencing, especially on farms, is that it is difficult for a person to immediately discern whether an electric fence is operating, not least because a permanent electric fence may extend for many kilometres, and the energiser may not be nearby. Some serious injuries, and even fatalities, have been caused by electric fences in the past.

One rudimentary solution for a person to determine if an electric fence is operating is to touch one of the wires with the back of their hand, while they are grounded. If a shock is felt, then it is determined that the electric fence is operating to some extent. If no shock can be felt, then more investigation is required. There are obvious drawbacks to this approach to determining the state of an electric fence. Firstly, electric fences are designed to be painful or at the very least sufficiently uncomfortable that it is undesirable to touch them. Secondly, only a limited amount of information can be gathered from briefly touching a wire of an electric fence - there is no measurement of characteristics such as pulse frequency, the consistency of the strength of the pulses, and the average pulse strength.

There are commercially available devices that can be used to address these issues without a person having to personally touch a wire of an electric fence. However these devices themselves suffer shortcomings. For example, they may be devices dedicated to this purpose alone, and are therefore inconvenient for a person to have to carry with them. Furthermore, they require physical contact with a wire of the electric fence, which can be inconvenient, not least because it may lead accidental contact with the wire. Object of the Invention

It is an object of the invention to provide an improved method of analysing the state of an electric fence.

Alternatively, it is an object of the invention to provide an improved device for analysing the state of an electric fence.

Alternatively, it is an object of the invention to address one or more of the disadvantages associated with the prior art, or to at least provide the public with a useful choice. Summary of the Invention

Preferred aspects of the invention are set forth in the appended claims. Particular embodiments are described below in non-limiting terms. According to a first embodiment of the invention there is provided a computer-implemented method of determining that an electric fence is energised, the method comprising:

receiving data representative of the strength of a signal detected in the vicinity of the electric fence over a time period;

analysing said data to identify a series of pulses in the signal indicating that the electric fence is energised. Preferably, the step of analysing said data comprises:

determining time spacings and/or frequencies of peaks in the signal to identify the series of pulses; and

assessing whether the time spacings and/or the frequencies of the peaks are indicative of an energised electric fence.

Preferably, the step of receiving data comprises receiving a time series of samples representative of the strength of an electric field detected proximate the electric fence.

Preferably, the time series is between 6 and 15 seconds long. More preferably, the time series is 10 seconds long.

Preferably, the step of analysing said data comprises:

dividing the time series of samples into a plurality of equal time intervals;

identifying a peak sample in each time interval, the peak sample being the sample with the highest absolute magnitude within the respective time interval; and

calculating a plurality of time differences between pairs of peak samples.

Preferably, the step of analysing said data comprises:

identifying a consistent frequency at which a plurality of the peak samples occurred in the time series of samples; and

identifying that the consistent frequency is within a range of frequencies assumed to be typical of the pulsing of an electric fence.

More preferably, the step of analysing said data comprises determining a plurality of pair frequencies based on the calculated time differences, the pair frequencies being respective frequencies of the pairs of peak samples.

Preferably, the method comprises the steps of:

calculating a plurality of pair frequencies between pairs of peak samples, each pair comprising: a first peak sample; and

a second peak sample, the second peak sample being the peak sample having the highest magnitude of all the peak samples in the time series before the first peak sample; identifying one or more possible pulse frequencies that could have produced each pair of peak samples; and

counting the occurrence of each possible pulse frequency. Preferably, the one or more possible pulse frequencies are identified by identifying integer multiples of each pair frequency that are within the range of frequencies assumed to be typical of the pulsing of an electric fence. More preferably, the range of frequencies assumed to be typical of the pulsing of an electric fence is 0.3-1.1 Hz. Preferably, the step of counting the occurrence of each possible pulse frequency comprises:

dividing the range of frequencies assumed to be typical of the pulsing of an electric fence into a first set of frequency intervals of equal size;

for each identified possible pulse frequency, adding a count to the frequency interval of the first set of frequency intervals, within which the possible pulse frequency falls.

Preferably, the step of counting the occurrence of each possible pulse frequency further comprises: dividing the range of frequencies assumed to be typical of the pulsing of an electric fence into a second set of frequency intervals, the frequency intervals of the second set overlapping the frequency intervals of the first set;

for each identified possible pulse frequency, adding a count to the frequency interval of the second set of frequency intervals, within which the possible pulse frequency falls.

More preferably, the second set of frequency intervals are of equal size to the first set of frequency intervals. More preferably, the frequency intervals of the second set overlap the frequency intervals of the first set by half the size of a frequency interval.

Preferably, the step of identifying that the series of pulses are indicative of being produced by the electric fence comprises identifying that an occurrence of one of the possible pulse frequencies is higher than all others of the possible pulse frequencies.

Preferably, the step of identifying that the series of pulses are indicative of being produced by the electric fence comprises:

identifying that the count of one frequency interval of either the first or the second set of frequency intervals is equal to or greater than a predetermined multiple of the count of any of the other frequency intervals of either the first or the second set of frequency intervals, as the case may be. Preferably, the predetermined multiple is two.

More preferably, the step of identifying that the series of pulses are indicative of being produced by the electric fence further comprises:

identifying that the count of one frequency interval of either the first or the second set of frequency intervals is greater than a predetermined quantity.

Preferably, the predetermined quantity is three.

According to a second embodiment of the invention there is provided an apparatus for identifying that an electric fence is energised, the apparatus comprising:

means for receiving a signal detected remotely from an electric fence over a time period; and means for analysing the signal to determine if the electric fence is energised.

Preferably, the apparatus is a mobile computing device. More preferably the apparatus is a smartphone or tablet computer.

Preferably, the means for receiving the signal comprises a jack of the mobile computing device, the jack being operable to detect the signal from the electric fence.

In some embodiments, the means for receiving the signal further comprises a peripheral device connected to the jack. Preferably, the jack is operable to detect the signal from the electric fence via the peripheral device.

Preferably, the jack is a headset or microphone jack, and the peripheral device connected to the jack has an electrical resistance typical of a microphone that the mobile computing device is configured to receive in the jack.

Preferably, the peripheral device connected to the jack comprises a phone connector connected to the jack, and a resistor connected between a microphone conductor and a ground conductor of the phone connector. Preferably, the means for analysing the signal comprises a processor configured to perform the method according to the first embodiment of the invention.

According to a third embodiment of the invention there is provided the use of a mobile computing device to identify that an electric fence is energised, the use comprising identifying that the electric fence is energised without contacting the electric fence.

Preferably, the use comprises operating the mobile computing device to detect a signal received at a jack of the mobile computing device. More preferably, the jack is a headset or microphone jack.

Preferably, the use comprises subjecting the jack to an electric field created by the electric fence so that the signal is representative of the strength of the electric field proximate the electric fence.

Preferably, the use comprises operating the mobile computing device to perform the computer- implemented method of the first embodiment of the invention.

According to a fourth embodiment of the invention there is provided the use of a peripheral device, operably connected to a mobile computing device, to identify that an electric fence is energised without contacting the electric fence.

Preferably, the mobile computing device is operable to identify that the electric fence is energised. In some embodiments, the mobile computing device is operable to perform the computer-implemented method according to the first aspect of the invention to identify that the electric fence is energised. Preferably, the mobile computing device is operable to receive, via the peripheral device, data representative of the strength of a signal detected in the vicinity of the electric fence over a time period, and analyse said data to identify that the electric fence is energised.

Preferably, the strength of the signal is representative of the strength of an electric field generated by the electric fence.

According to a fifth embodiment of the invention there is provided a peripheral device for detection of an electric field generated by an electric field source, comprising:

means to generate a first signal representative of the strength of the electric field without physical contact between the peripheral device and the electric field source; means to provide a second signal to a mobile computing device, the second signal being representative of the strength of the electric field;

means for causing the mobile computing device to process the received signal from the peripheral device as an audio input signal; and

means to control the magnitude of a voltage of the second signal provided by the peripheral device to the mobile computing device.

Preferably, the means to provide the second signal to the mobile computing device comprises means for operably connecting the peripheral device to a jack on the mobile computing device.

Preferably, the means for operably connecting the peripheral device to the jack comprises a phone connector comprising microphone and ground conductors.

Preferably the phone connector comprises a 3.5mm phone connector. Preferably, the jack is a socket configured to receive the 3.5 mm phone connector.

Preferably, the jack is a headset jack.

Preferably, the phone connector comprises at least three conductors. More preferably, the phone connector comprises four conductors.

Preferably, the voltage of the second signal is the voltage across the microphone and ground conductors. Preferably, the peripheral device comprises means to allow the microphone conductor to receive a greater absolute magnitude charge than the ground conductor.

Preferably, the peripheral device comprises means to limit the voltage of the second signal to within a predetermined range having a maximum having a maximum limit equal to or lower than a maximum allowable voltage that can be safely applied between the microphone and ground conductors.

Preferably, the means to limit the voltage of the second signal comprises a pair of diodes configured to short-circuit the peripheral device if the voltage of the second signal is higher than the predetermined range. Preferably, the diodes are connected in parallel with each other and between the microphone and ground conductors, oriented oppositely to each other, and each having a threshold voltage equal to or lower than the maximum allowable voltage.

Preferably, the diodes are connected in parallel with each other between the output terminals of the transformer.

Preferably, the diodes are Schottky diodes.

Preferably, the peripheral device comprises a resistor connected between the microphone and ground conductors, and the peripheral device has an electrical resistance typical of a microphone that the mobile computing device is configured to receive in the jack.

Preferably, the electrical resistance of the peripheral device is approximately 2.2 kQ.

Preferably, the peripheral device comprises means to prevent direct current flow between the microphone and ground conductors through any components except for the resistor connected between the microphone and ground conductors.

Preferably, the means to prevent direct current flow comprises two capacitors connected in series between the microphone and ground conductors. Preferably, each capacitor has a capacitance of 10 μΡ.

Preferably, the peripheral device comprises a transformer having input terminals and output terminals, configured to generate an increase in voltage between the first signal and the second signal. Preferably, the transformer is connected between microphone and ground conductors. Preferably the transformer is a pulse transformer.

Preferably, the peripheral device comprises a transformer resistor connected between the input terminals of the transformer. Preferably, the transformer resistor comprises a resistance of 100 Ω.

Preferably, the means to generate the signal comprises an antenna having at least one conducting element and an antenna resistor connected in series with the at least one conducting element.

Preferably, the antenna resistor has a resistance of 100 Ω. Preferably, the mobile computing device is a mobile communication device. Preferably, the mobile communication device is a smartphone or a tablet.

Preferably, the electric field source is an electric fence.

According to a sixth embodiment of the invention there is provided a peripheral device for detection of an electric field generated by an electric field source, comprising:

means to generate a first signal representative of the strength of the electric field without physical contact between the peripheral device and the electric field source;

means to provide a second signal to a mobile computing device via at least two connectors, the second signal being representative of the strength of the electric field;

means for causing the mobile computing device to process the received signal from the peripheral device as an audio input signal; and

means to allow one of the two connectors to receive a greater absolute magnitude charge than the other of the two connectors.

According to a seventh embodiment of the invention there is provided an electric field detection system for detection of an electric field generated by an electric field source, comprising:

a mobile computing device; and

the peripheral device according to the fifth or sixth embodiments of the invention.

Further aspects of the invention, which should be considered in all its novel aspects, will become apparent to those skilled in the art upon reading of the following description which provides at least one example of a practical application of the invention.

Brief Description of the Drawings

One or more embodiments of the invention will be described below by way of example only, and without intending to be limiting, with reference to the following drawings, in which:

Figure 1 is a flow chart showing a method according to an embodiment of the invention;

Figure 2 is a plot showing the magnitude of sample values collected over time, by a method according to an embodiment of the invention; Figure 3 is a plot showing a 3D plot showing counts within bins according to an embodiment of the invention;

Figure 4 is a schematic illustration of an electric field detection system according to an

embodiment of the invention; and

Figure 5 is a circuit diagram of a peripheral device according to an embodiment of the invention.

Detailed Description of Preferred Embodiments of the Invention

In preferred embodiments, the present invention is performed using a mobile computing device, for example a mobile device such as a device that is purpose-built and dedicated to performing the methods of the present invention. Alternatively, embodiments of the invention may advantageously be performed by a device such as a smartphone or a tablet configured to perform the invention. This enables anyone with such a device to benefit from the invention, when the device is suitably programmed. The way in which such a device may be configured to operate in embodiments of the invention will become apparent after reading the following description. In general terms, the device is configured to perform a computer-implemented method according to an embodiment of the invention by virtue of a processor, which may be programmed by suitable software. In the case where a smartphone (phone) is used to perform the invention, the smartphone may have an application

(commonly known as an "app") installed on the phone. The app may be dedicated to performing a method according to an embodiment of the invention. In other cases, embodiments of the invention may be implemented via more general software, such as a web browser. In some cases, some of the method steps may be carried out remotely from the mobile computing device.

In preferred embodiments the device has the capability for contactless detection of an energised electric fence. A particular example of contactless detection will be explained below, along with exemplary hardware that provides said capability.

By way of example, the invention will be described in places with reference to the contactless detection of an energised electric fence using a smartphone, often referred to as a "phone".

When a fence being tested is an energised electric fence, the electrified wire or wires of the fence produce an electric field in their vicinity when they are periodically charged by the fence energiser. This electric field affects the terminals of the headset jack of the phone. If the phone is configured to be making a sound recording using the headset jack as a source of audio input, the phone generates a sound file that reflects the effect of the electric field produced by the pulse of the electric fence. The presence of periodic pulses in the sound file can then be identified, indicating that the fence being tested is electric and is operating / energised. The pulses may be registered in the recording as spikes, or recorded sample values having a magnitude much greater than other sample values recorded immediately before or after the pulse.

Figure 1 is a flow chart showing a method 10 of identifying if an electric fence is energised, according to a preferred embodiment of the invention. The method 10 in this example is performed on a smartphone via an application (app) having a graphical user interface with which a user can interact. In other embodiments the user interface may be a webpage, and the method may be performed in part by a remote processor which provides results or other outputs to the webpage via a remote server.

The method 10 is, in this example embodiment, performed using a smartphone, and the method steps are performed by a processor controlling the hardware of the smartphone. For this reason, the steps will be described below as actions performed by the smartphone processor.

It is to be understood that an electric fence is energised if it is operating. A common electric fence will be charged with a pulse periodically. The term energised is not limited to the instances in time during the pulses. If an electric fence is pulsing, it is to be considered to be energised.

When a user encounters a fence, and wishes to determine whether or not the fence is indeed electric and/or whether or not it is operating, the user opens on the smartphone an app programmed to control the processor to perform the method 10, either completely or partially. There are various options for how the app and its user interface may be designed, however to begin detecting an electric fence, in preferred embodiments the user may provide an input to the app indicating their desire to analyse a fence, and the application may then proceed to control the processor to perform the steps of method 10. In some embodiments the method 10 comprises an initial calibration step 11, which may be required for some devices but not others. The calibration step 11 is described further below.

In step 12 the processor makes a sound recording by operating the smartphone to make a recording of the signals detected through the hardware of the smartphone associated with an external microphone (e.g. the hardware adapted to receive input from a headset) which in preferred embodiments is a jack in the smartphone that receives the plug of a headset or other type of microphone. To begin the recording the user holds the smartphone proximate a wire of the fence and oriented such that the external microphone jack of the smartphone is as close as possible to the wire without actually touching the wire.

The actual distance from the wire at which the smartphone can perform the method depends on various factors such as the strength of the electric field, the sensitivity of the smartphone to incoming signals from its external microphone jack, and the magnitude of noise in the recording. The external microphone jack of the phone can be sufficiently close to the wire such that the phone can detect the pulses of the electric fence, but to ensure the electric field at the distance of the jack is strong enough that the pulses of the fence as registered in the recording are detected and are sufficiently stronger than the noise of the recording, the closer the jack is held to the wire, the better.

The processor controls the smartphone to make a recording as if it is making a recording of audible sound using the headset jack as the source of audio input, and creates a file in WAV format comprising a series of samples having values representative of the strength of the electric field created during the recording. In other embodiments, the recording may be stored in any suitable format.

The sound recording may be between 6 and 15 seconds long, for example 10 seconds long. This length of time is long enough that the fence is able to pulse a sufficient number of times for enough data to be collected, while still being short enough that the collection of data is not inconvenient.

After the processor has controlled the smartphone to produce the recording, step 13 of the method 10 is performed. Step 13 comprises initial processing of the recording. In this embodiment, the processor calculates and saves the absolute values of the samples, in order in an array along with the sample rate. Absolute values are used to allow easy comparison of magnitudes of individual samples, allowing for easy detection of peak values.

Step 14, peak detection, is then performed. In this embodiment, the processor ignores the first 0.1 seconds of the recording. The reason for this is to prevent any transient effects created as a result of beginning the recording from influencing subsequent processing.

The processor then divides the remainder of the recording into intervals of 0.8 seconds to be analysed independently. In this embodiment an interval size of 0.8 seconds is used as it is a similar time period to a typical time delay between sequential pulses of a typical electric fence energiser. For each interval, the processor identifies a peak sample. The peak sample within an interval is the sample within that interval having the greatest magnitude. The processor stores the peak value and the time at which it occurred. In other embodiments, interval sizes of other than 0.8 seconds may be used. Figure 2 shows a plot 20 of the magnitude of samples collected over time during the recording. Peak samples 21 can be seen occurring periodically.

After an appropriate data set of peak samples has been prepared, step 15 is performed. In general terms, at step 15 the processor identifies whether or not there is a consistent frequency at which the peaks samples occurred during the recording, and if so, whether or not it is likely to have been produced as a result of the fence being energised - i.e. whether or not the peak samples are actually spikes in the recorded data resulting from the electric field produced proximate the electric fence wire as it is energised with a pulse. Any suitable method of identifying that the peak samples are occurring with a frequency typical of an electric fence may be used. In the exemplary embodiment described here, step 15 comprises "frequency based bin allocation".

In general terms, the method involves considering a frequency range within which pulsing of an electric fence would be expected to occur (i.e. a range of frequencies assumed to be typical of the pulsing of an electric fence). At sub-step 151 the processor defines the frequency range as between 0.3Hz to 1.1Hz, as a typical electric fence energiser pulses with a frequency within this range. In this embodiment, at sub- step 152 the processor divides the range into 200 evenly sized frequency intervals or "bins" (i.e. forming 200 intervals being 0.3-0.304Hz, 0.304-0.308 Hz ... 1.096-1. lHz). Other frequency ranges and other intervals or number of bins may be used in other embodiments of the invention.

In this embodiment, at sub-step 153 the processor calculates a pair frequency by calculating the time difference between the time at which a peak sample occurs, and the time at which the peak sample having the largest magnitude of all the previous peaks occurred. The processor then converts the period of time (i.e. in seconds) into a frequency (i.e. in Hertz), by calculating the inverse of the time difference, to obtain the pair frequency.

As the time difference between a particular peak sample and the highest magnitude previous peak sample is used to calculate frequency, the pair frequencies may be much lower than the actual frequency at which the fence is operating, because the two peak samples that are compared may not have resulted from sequential pulses of the fence - i.e. the fence may have pulsed a number of times between the two particular peak samples that are being used to calculate a pair frequency. For this reason, from a single pair of compared peak samples, it can only be deduced that the actual operating frequency of the fence is one of a number of possible integer multiples of the calculated pair frequency of the two peak samples being compared. For example, if a pair frequency is 0.2Hz, then this is indicative that the fence could be pulsing at any one of 0.2Hz, 0.4 Hz, 0.6Hz, 0.8Hz, IHz, 1.2Hz etc. In this exemplary method, there is not enough information obtained by comparing a single pair of peak samples alone to determine which of these possibilities is the true operating frequency of the fence. A reason that in the method 10 the processor compares a particular peak sample with whichever of the previous peak samples had the largest magnitude of all the previous peak samples, in order to calculate a pair frequency, is to reduce the chance of a peak sample being compared with a previous peak sample that was not the result of a pulse in the fence. For example, if a recording made using the method 10 is divided into intervals of 0.8 seconds, but a fence is operating with a frequency of only one pulse each second, then there will be some intervals of the recording during which there is no pulse produced by the fence. This will result in the peak sample of that interval being produced by noise. By comparing a peak sample to whichever previous peak sample had the highest magnitude, the method avoids a peak sample being compared to a previous peak sample produced by noise, as it would be likely to have a magnitude lower than that which would have been produced by an actual pulse from the fence.

In other embodiments of the method the processor may calculate pair frequencies using sequential peak samples. In some embodiments the method may also comprise a step in which the processor compares the magnitude of all the peak samples to one another, in order to check whether or not there is consistency and/or to remove any outliers.

Each of the bins within the range of frequencies assumed to be typical of the pulsing of an electric fence (in this example 0.3-l.lHz) has an associated count. After a pair frequency between two peaks has been calculated, at step 154 the processor adds a count to each of the bins that cover a frequency interval that the calculated pair frequency indicates may be the operating frequency of the fence. More specifically, the processor first checks whether or not the calculated pair frequency is higher than the minimum of the expected frequency range (0.3Hz in this example), and if not it multiplies the originally calculated pair frequency by increasing sequential integers until a possible pulse frequency is reached that is above the minimum of the expected range of possible pulse frequencies. The processor then adds a count to the bin having a frequency interval within which the possible pulse frequency falls. The processor then continues multiplying the pair frequency until a possible pulse frequency is reached that is larger than the upper limit of the expected frequency range (1.1Hz in this example).

The processor then repeats sub-step 153 and sub-step 154 with the remaining peak samples, until all peak samples have been compared with a previous peak sample, and all pair frequencies have been used to add counts to bins. Preferably, sub-steps 153 and 154 will begin by comparing the second peak sample to the first peak sample, and then comparing the third peak sample with whichever of the first or second peak samples had the greatest magnitude, and so on. In some embodiments, the processor may stop repeating sub-steps 153 and 154 when a sufficient number of counts have been added to the bins for step 16 of the method to be performed, which is described below.

As the frequency calculated by comparing pairs of peak samples may indicate a number of possible pulse frequencies of the fence, a count may be added to many bins for each compared pair frequency. However, for a fence pulsing at a relatively consistent frequency, the true operating frequency of the fence will be identified as a possible pulse frequency, and a count added to the appropriate bin, with every pair frequency. The count of the bin defined by the frequency interval covering the operating frequency of the fence will therefore be increased with every comparison. With many comparisons of peak samples, the bin covering the operating frequency of the fence will have a count significantly higher than the other bins.

Figure 3 shows a plot of the number (i.e. "magnitude") of counts 301 at various frequencies as steps 153 and 154 repeat over time.

After the processor has completed all comparisons of peaks and allocated counts to bins, step 16 comprises making a decision about whether or not the fence is energised.

In this embodiment, the processor performs step 16 by comparing the count of the bin having the highest count, to the counts of the other bins. The method 10 in this example will make a decision that the electric fence is energised if the bin with the highest count has a count greater than three, and if the bin with the highest count has a count equal to or greater than a predetermined multiple of the count of the bin having the second highest count. In this embodiment, the predetermined multiple is two, however in other embodiments other multiples may be used. The multiple used is, in some

embodiments, affected by the length of the recording and the actual pulsing frequency of the electric fence - for example, in a short reading, there are fewer peak samples available for comparison, meaning a lower multiple is required to positively determine the presence of an energised electric fence, otherwise a decision might not be reached (as count can only be increased with more compared peak samples). If the relevant criteria are met, the application will notify the user that the fence is operating, along with any other available information such as the fence's pulse frequency. In some embodiments step 16 may be performed after every time sub-steps 153 and 154 are performed, until either a decision can be made that the fence is energised, or all peak samples have been compared with a previous peak sample.

Multiple Sets of Bins

In preferred embodiments, two sets of frequency bins are used. The first set of bins are defined by the processor as described above with a series of frequency intervals to cover the frequency range of pulsing expected for an electric fence, for example of 0.3-l.lHz. The bins in the second set are of the same size and number as the bins in the first set but overlapping the limits of the first set, with limits defined offset from the limits of the first set of bins by half the size of the frequency intervals. As an example, a first set of bins may be defined by the intervals 0.300-0.304 Hz, 0.304-0.308 Hz, 0.308-0.312 Hz etc., and the second set of bins may be defined by the intervals 0.302-0.306 Hz, 0.306-0.310 Hz, 0.310-0.314 Hz etc. When the processor compares a number of pairs of peak samples and calculates a number of possible pulse frequencies having values near the border between two bin frequency intervals, variability in the calculated possible pulse frequencies may result in some calculated possible pulse frequencies falling within the first interval, and others falling within the second interval. If this happens, then as further peak samples are compared, the count of both bins will be increased over time, and neither bin will obtain a dominant count. However, if a second bin set is defined with frequency intervals overlapping those of the first bin set, there will be a single bin in the second bin set that will receive a count for any calculated possible pulse frequencies that do not consistently fall within a single interval of the first bin set. The variability in calculated possible pulse frequencies may be caused by factors such as inconsistency in the pulsing produced by the fence energiser or rounding during calculation.

When the processor performs the step of making a decision about whether or not the fence is operating, if either set of frequency intervals fulfils the relevant criteria (e.g. having a frequency interval with a count at least double any other frequency interval) then the decision may be made that the fence is operating. In other embodiments, the size of the bins in the second set of bins may not be equal to the size of the bins in the first set, and the limits may not all be defined by being offset by half the size of the frequency intervals of the first set of bins. For example, the bins of the second set may be smaller (in which case the limits will not all be offset by half the size of the frequency intervals of the first set) or the limits of the bins of the second set may be offset by another amount, such as a third of the size of the frequency intervals of the first set. In both these examples, the overlap between bins will be sufficient that each bin of the second set will safely receive the counts for pair frequencies that fall near the limits between two neighbouring bins of the first set. Where a second set of bins is used to achieve this advantage, the limits of the bins in the second set of bins should be separated from the limits of the bins in the first set by an amount greater than the uncertainty of each pair frequency measurement - this can be accomplished easily by separating the limits to the maximum possible extent, as in the preferred embodiment of method 10 described above.

Calibration

As previously mentioned, in some embodiments of the method 10 the processor may perform an initial calibration step 11.

This step may not be required in all cases. In some devices, such as smartphones, there is an amount of noise present in the phone to some extent. The extent of this noise can vary greatly between phones. In some embodiments the app may have stored information regarding which phones/devices are known to have negligible noise, in which case the app may determine that if it is being run on one of those particular phones, the calibration step may be dispensed with. In other embodiments of the invention the calibration step may be performed in all cases, either once for each device or before every recording.

During the calibration step 11 the processor controls the smartphone to take an initial recording, away from an electric fence, and analyse the recording for noise. Depending on the amount of noise and the nature of the noise, the processor may then take steps to reduce the effect that the noise may have on operation of the method. For example, if periodic noise is detected, the processor may apply a threshold when the method is performed, whereby only peaks exceeding the threshold are considered. For example, a threshold could be set at 130% of the maximum reading obtained during calibration, so that only peaks exceeding the maximum of the calibration reading by at least 30% are considered. Other thresholds in the range 10-50%, such as 10%, 15%, 20%, 50% and the like, could also be used in other embodiments of the invention, and still other threshold may be used in other embodiments. An example threshold 22 shown in Figure 2 illustrates an example threshold positioning - slightly above the noise level so that that only the periodic peaks 21 are taken into account.

Further Embodiments of Methods of Determining that an Electric Fence is Energised

Alternative methods could be used to identify peaks within a set of data and make a decision. A reason why the method 10 is used in preferred embodiments is because the analysis can be performed in real time during the reading of an electric fence, or alternatively the analysis can be performed after the entire reading is taken. For example, if the method 10 involved performing the analysis in real time, the processor may record data to a primary file, but copy each 0.8 second time interval to a secondary file as each 0.8 second interval elapses. As each 0.8 second time interval is recorded, its peak value can be compared to the previous largest peak recorded, and counts added to the bin scores. When the method is performed on a device via an application, the user may hold the device proximate the fence until the application notifies the user of the decision that has been made.

While the exemplary method 10 involved a conversion from time to frequency, the method could also be performed by considering time alone. In such an embodiment, rather than a range of frequencies, a range of times may be considered - i.e. instead of pulses being expected to occur at a frequency falling between 0.3 Hz and 1.1 Hz, pulses may be considered to occur spaced apart by a time period of between 0.9 seconds and 3.3 seconds. The "bins" could then be created as intervals of seconds, and the time difference between a pair of pulses would not be converted into frequency. However, if a fence is determined to be operating with a consistent time difference between pulses, the identified time difference may be converted into frequency to be provided as information to the user. It should be understood that the step of making a decision comprises providing an output to the user, which may or may not be a decision. For example, rather than providing the user with a yes or no answer in relation to the fence being electric and operating, the app may instead advise the user that a) the fence is operating, or b) that the analysis did not suggest the fence is operating. This provides a level of transparency and acknowledges any potential for error. In some embodiments there may be further messages available for the app to provide, for example a message advising the user that the method identified periodic phenomenon, but that the identified period is not of a length typical of an electric fence.

In some embodiments the app may provide a level of confidence (either quantitatively or qualitatively) in the decision that has been made. In some embodiments the level of confidence may be determined by, for example, the number of peak samples identified. In some embodiments the level of confidence may be determined by the magnitude of the peak samples relative to the noise level (for example by calculating the ratio of the magnitude of each peak sample to the median sample magnitude in the same interval). In some embodiments the level of confidence may be determined by consistency in the recording, for example the consistency in the magnitude of the peak samples. In some embodiments a level of confidence may be determined by the criteria that has been met - for example, if a user makes a longer recording, the count of the frequency interval bin with the highest count will likely be a higher multiple of the count of the bin having the second highest count, than if the user was to make a shorter recording.

Peripheral Device

In some embodiments of the invention, a peripheral device is used in combination with a mobile computing device, such as a phone, with the ability to receive and analyse a signal indicative of the strength of an electric field. The combination of peripheral device and phone can be used as a system to detect and analyse the state of an electric field. In preferred embodiments, the phone performs a method, such as the method described above, to analyse a signal received at its headset jack, the signal being representative of the strength of an electric field at the peripheral device. The peripheral device may work in a similar way to the headset jack when the headset jack is used alone, with the peripheral device being an extension of the jack terminals.

Some mobile computing devices are able to receive the signal reflecting the strength of the electric field on their own using the headset jack, with or without any additional detection device plugged into the headset jack. However, others require a peripheral device to be plugged into the headset jack and identified by the mobile device as a microphone, before the mobile device will allow for the use of the headset jack as a source of data input. Even for those mobile computing devices that are able to receive such a signal without any additional detection device, there may be benefits in using an additional device, for example to augment the received signal. Typically it is the software, such as an operating system, running on a mobile computing device that determines whether or not a peripheral device needs to be plugged into the headset jack of the device to enable the use of the headset jack as a source of audio input, however in some devices the hardware of the device may require a connector to be inserted into the headset jack. Typically, the headset jack of a mobile device running the Android or Windows operating systems is able to be used as a source of audio input without a peripheral device being plugged into the headset jack, whereas devices running Apple's iOS typically require a peripheral to be connected before the device can be operated to receive audio data via the headset jack.

Different steps may be required depending on the particular type and/or model of the mobile computing device or the software running on the device. For example, in some devices, re-routing both the audio and the microphone to the external headset jack, or whichever jack that may be desired, can be accomplished using the same command. In other devices, the audio and microphone may be able to be re-routed separately. Different devices may require different peripherals to be re-routed - for example, some devices require only the microphone input to be modified to be received via the headset jack, however other devices require both the audio and microphone input to be swapped for the change to take effect.

The headset jack of a mobile computing device such as a smartphone is usually a socket configured to accept a 3.5mm phone connector. It will be understood that the term "phone connector" refers to the family of connectors often used for analogue signals, and often audio signals. The term "phone connector" therefore is not limited to a connector that can only be used with a mobile phone or other telecommunications device, but includes connectors of this type that can connect to other types of mobile computing device. In some embodiments, the peripheral device comprises means for causing the mobile computing device to process the received signal from the peripheral device as an audio input signal. For example, the presence of a phone connector inserted into the mobile device's peripheral jack may on its own be enough to be identified as a connected peripheral device (for example if the mobile device only requires a mechanical switch to be activated by the inserted phone connector, of if the mobile device only requires a circuit to be completed between conductors of the socket). In such a case, the mobile device then allows the headset jack to be used as a source of audio input, and the method of identifying that an electric fence is energised can be performed using the mobile device with nothing more than a phone connector inserted into the headset jack. In some embodiments, the mobile device may require more than the presence of a phone connector alone to be inserted into the headset jack before identifying the peripheral device as a microphone and enabling the headset jack as a source of data input. For example, the mobile device may require the peripheral device be plugged into the headset socket to complete a circuit between conductors treated as microphone and ground conductors and have an electrical resistance typical of a microphone. An example of a basic suitable peripheral device is therefore a phone connector with a resistor added between the ground and microphone conductors. In some embodiments a 2.2 kQ resistor is used, because 2.2 kQ is a resistance that a mobile device such as a mobile phone or tablet would typically recognise as being the resistance of a microphone. The phone connector and accompanying resistor of the peripheral device in such an embodiment would therefore form part of a means for causing the mobile computing device to process the received signal from the peripheral device as an audio input signal. In preferred embodiments the peripheral device does not comprise an actual microphone able to register audible sound during the recording of electric fence pulses.

Peripheral devices according to preferred embodiments may be in the form of an adapter comprising means to operatively connect to the mobile computing device, in order to enable or enhance an ability of the mobile computing device to receive data representing the strength of an electric field. The use of a peripheral device can also increase the effectiveness of the mobile device at detecting an electric field produced proximate an electric fence, because the peripheral device can act as an antenna. The peripheral device in such a case may be considered a detector because the peripheral device either is, or comprises, a means to generate a signal representative of the strength of an electric field produced by an electric field source, without contact between the peripheral device and the electric field source.

While a peripheral device such as those disclosed above are suitable for allowing operation of an electric fence to be detected, it is advantageous to design a peripheral device to even better act as a detector, enabling more sensitive detection of an electric field, and preferably having further features such as means to process the data provided to the mobile device.

Figure 4 shows a schematic illustration of an electric field detection system 40 according to an embodiment of the invention.

Electric field detection system 40 comprises smartphone 41 and peripheral device 42 connected to the headset jack of the smartphone 41.

Peripheral device 42 comprises resistor 43. The resistor 43 is appropriately selected, as is discussed further in relation to Figure 5, so that the resistor 43 has a resistance that a typical mobile

communication device such as smartphone 41 would recognise as a microphone, enabling the use of the smartphone's headset jack as a source of audio input.

Peripheral device 42 also comprises means to generate a signal representative of the strength of an electric field, for example in the form of antenna or aerial 46. The antenna 46 is connected to input terminals of a transformer 45, which has output terminals connected to the smartphone 41. A voltage drop is created across the input terminals of the transformer, the magnitude of which depends on the strength of the electric field to which the antenna 26 is subjected. In this embodiment the transformer 45 may generate an increase in voltage provided to the smartphone 41, and also provides isolation between the antenna and the rest of the circuit.

The transformer 45 may also comprise means to control the way in which the signal is provided to the smartphone 41. In particular, it may be configured to provide the voltage such the microphone terminal of the smartphone's headset jack is provided a non-zero charge, while the ground terminal of the headset jack is provided a substantially zero charge. This is advantageous for safety of the smartphone 41, given charging the ground terminal of the headset jack may be damaging to some phones.

The peripheral device 42 also comprises protection circuitry 44. In particular, protection circuitry 44 comprises means to control the magnitude of the voltage that is provided to the headset jack to within a predetermined range having extremes that are safe for the smartphone to receive. This reduces the risk of signals being detected by the peripheral device that are sufficiently strong to cause harm to the peripheral device or the mobile computing device to which it is connected. Figure 5 shows a circuit diagram of the design of a peripheral device 50 according to an embodiment of the invention.

Peripheral device 50 is shown connected to jack 100 of a mobile computing device such as a smartphone, tablet or the like (hereafter "smartphone"). The connection may be made with a 3.5mm phone connector. The phone connector may have a minimum of two conductors, and during operation the smartphone may acquire data from the jack 100 treating one conductor as a microphone conductor and the other as a ground conductor. The connection of the peripheral device 50 to the jack 100 forms a means to provide a signal to the mobile computing device. Most smartphones have peripheral jacks that accept a phone connector having four conductors named as "tip", "ring 1", "ring 2" and "sleeve". This type of phone connector is known as a TR S connector. Commonly "ring 2" is used as the microphone conductor and the sleeve is used as the ground conductor, however some smartphones treat the sleeve as the microphone conductor and "ring 2" as the ground conductor. The example peripheral device 50 makes connections with the "ring 2" conductor (identified as conductor connection 3 in Figure 1), and the sleeve conductor (identified as conductor connection 4 in Figure 1).

Resistor 55 is connected between the conductor connections 3 and 4, and has a resistance typical of the resistance of a microphone designed for use with the smartphone. A smartphone constantly applies a DC voltage (for example 1.5V) between the microphone conductor and the ground conductor of its jack - i.e. to conductor connections 3 and 4. The smartphone expects a particular range of resistances identified between the microphone and ground connectors in order to identify the connected peripheral as a microphone. In this example embodiment resistor 55 has a resistance of 2.2 kn, chosen because this is a typical resistance of a microphone, enabling the smartphone to identify the peripheral device 50 as a microphone, and therefore causing the smartphone to process the received signal from the peripheral device as an audio input signal.

In this embodiment, the peripheral device 50 includes means to generate a first signal, representative of the strength of an electric field, comprising an antenna or aerial 62. Antenna 62 in this embodiment comprises a conducting element in the form of a length of wire. Preferably the wire is relatively long, as a longer wire will allow a stronger charge to be produced in the antenna. There is not a specific minimum or maximum length of wire required to form antenna 62, and the actual length used may be as long as possible while still being a convenient length for the user.

The antenna also comprises an antenna resistor 61, which in this embodiment is placed in series with the conducting element, to mitigate the risk of damage to the peripheral device 50, or the smartphone to which it is connected, in the event that the antenna becomes very highly charged. The antenna resistor 61 is an optional feature of the peripheral device, but advantageous in mitigating the risk of damage.

A smartphone is typically designed to receive signals on at its headset jack having particular properties. For this reason, it is preferable that the peripheral device 50 is able to process, alter or otherwise convey the signal generated by the antenna to produce the signal that is to be provided to the microphone and ground conductors of the headset jack. More particularly, the peripheral device 1 comprises means to provide a second signal to the mobile computing device, the second signal still being representative of the strength of the electric field, but possibly having different properties to the first signal generated by the peripheral device 50 - i.e. the signal provided to the jack 100 may have different properties than the signal generated at the antenna 62. In this embodiment, the peripheral device comprises means to limit the magnitude of the voltage between the conductors 53 and 54. Any suitable means may be used in various embodiments of the invention, and in this embodiment, peripheral device 50 comprises two diodes 57 and 58 connected in parallel to each other between the conductor connections 53 and 54.

If the antenna 62 becomes charged to such an extent that, if the resulting potential difference across the conductor connections 53 and 54 would be higher than is safe or desirable for the smartphone, one of the diodes 57 and 58 shorts the circuit, preventing a large voltage from being applied across the microphone and ground conductors of the smartphone's headset jack 100. Two diodes are used, connected in parallel to each other between the conductor connections 53 and 54 and oriented oppositely, so that they together can protect from a large potential difference in either direction - one diode will short the circuit in the case of a large positive voltage, while the other diode will short the circuit in the case of a large negative voltage. The diodes 57 and 58 do not short the circuit during normal operation of the peripheral device 50 (i.e. when the antenna is not charged excessively) because they have threshold voltages that are higher than the voltages that will be applied to the conductors 53 and 54 during normal operation. This means they will only act as conductors if the voltage is unsafe. In this example embodiment the diodes 57 and 58 are Schottky diodes. Schottky diodes are advantageous for this use because of their fast response and low threshold voltages.

In this preferred embodiment, an acceptable range of voltage between the conductor connections 53 and 54 is approximately ± 0.25 V, as this is a range typically expected from a microphone intended for use with the headset jack of a smartphone. Therefore, in this embodiment the Schottky diodes 57 and 58 have threshold voltages of 0.25 V or slightly higher. In other embodiments the threshold voltages of the diodes 57 and 58 may differ somewhat.

In this embodiment, a transformer 59, providing transformer isolation between the antenna 62 and the circuitry connected to the jack 100, is included in the circuit of peripheral device 50. The transformer 59 has output terminals connected between the conductor connections 53 and 54, in parallel with the diodes 57 and 58. Transformer 59 in this embodiment is a pulse transformer, chosen for its small size and also because the input received by the antenna is expected to be a pulse. The transformer 59 has input terminals connected to the antenna 62 and antenna resistor 61. Transformer 59 advantageously provides a means to control the magnitude of a voltage of the second signal provided by the peripheral device to the mobile computing device, as it can adjust the voltage provided to the smartphone's jack 100. When protection circuitry is included in the peripheral device, for example the diodes 57 and 58 of peripheral device 1, the transformer 59 may advantageously increase the voltage provided to the smartphone to provide a stronger signal.

A transformer resistor 60 is connected in parallel to the input terminals of the transformer 59, to provide a return path for the current, and advantageously apply a voltage drop across the transformer based on current. Transformer resistor 60 is optional however, where the transformer 59 induces a potential difference across itself based on the induced current on the antenna, although a transformer resistor 60 can advantageously augment this potential difference.

Two capacitors 56 are connected to isolate the diodes 57 and 58 and the output terminals of the transformer 59 from the DC circuit created between the conductor connections 53 and 54 and the resistor 55, with one capacitor 56 connected in series on either side of the parallel combination of the diodes and transformer. In this particular embodiment the capacitors each have a capacitance of 10μΡ. The capacitors 56 prevent current caused by the DC voltage applied by the smartphone across the microphone and ground connectors from flowing through the rest of the peripheral device 50, while allowing the current to flow through the resistor 55, enabling the smartphone to identify the connected device as a microphone. The capacitors 56 for this reason may in this embodiment also be considered to help cause the mobile computing device to process the received signal from the peripheral device as an audio input signal.

In some embodiments of the invention in which no protection circuitry is included, the capacitors 6 may not be present. Furthermore, when the peripheral device includes protection circuitry, only one capacitor may be used in some embodiments, as one capacitor is enough to prevent the constant DC voltage applied by the smartphone across its microphone and ground conductors from shorting through one of the diodes. Two capacitors are preferable however, as they even out the signal propagated from the antenna to the smartphone's conductors, which is advantageous in the design of a peripheral device that can be used with either of the commonly used standards of TR S connector.

The structure of the circuit of this preferred embodiment of the invention therefore comprises two sub- circuits in parallel between the microphone and ground connections of a smartphone's jack. One of the sub-circuits includes only a resistor imitating the resistance of a microphone, which allows direct current to flow constantly from the microphone to ground connector, enabling the phone to recognise the peripheral device as a microphone. The other sub-circuit includes a time varying voltage source based on the strength of an electric field that the peripheral device detects. In parallel with the voltage source is protection means (e.g. the diodes). The combination of voltage source and protection means is isolated at each end of the sub-circuit with a capacitor, in order to prevent the 1.5V _DC from causing DC flow through this route. The voltage source is in this embodiment a transformer to which an antenna is connected - the antenna becoming charged as a result of being subjected to an electric field, the charge causing a voltage drop across input terminals of the transformer, which causes a voltage drop over output terminals of the transformer. One advantage of this antenna design is that it allows for the microphone conductor of the smartphone to receive a greater absolute (i.e. positive or negative) magnitude charge than the ground conductor. The preferred embodiment enables the voltage resulting from detection of an electric fence to be provided to the smartphone by charging the microphone conductor rather than the ground conductor, regardless of which conductor standard is used by the smartphone, due to the ground conductor being driven. A higher proportion of charge will therefore be received by the microphone conductor, regardless of whether a smartphone uses the OMTP standard (where the smartphone takes microphone input from the ring 2 of a T RS phone connector) or the CTIA/AHJ standard (where the smartphone takes microphone input from the sleeve of a TRRS phone connector). There is risk that applying a voltage to the ground conductor may be more hazardous to the phone, even if the smartphone is still able to successfully use the data to identify that an electric fence is energised.

Further Embodiments of Peripheral Devices

Some embodiments of the invention may include only some of the components of the preferred embodiments such as are included in the peripheral device 50.

In some embodiments a peripheral device may not include a resistor between the microphone and ground conductors of a phone connector. However, this is less advantageous than the preferred embodiments because the peripheral device may not be able to be used as a source of an audio signal by the software on a smartphone, if the smartphone's software requires a resistance typical of a microphone to be detected between microphone and ground conductors.

In some embodiments the peripheral device may not include a dedicated antenna component, such as a length of wire or other conducting element, however this is less advantageous because the strength of the signal generated may be lower, meaning the likelihood of errors occurring in the analysis of the signal may be higher.

In some embodiments the transformer may not be included, however this is less advantageous because the voltage generated would not be able to be increased, and also it would not be able to be controlled in order to ensure that the microphone connector is receives charge while the ground connector remains substantially not charged.

In some embodiments there may not be protection circuitry, however this is less advantageous as it provides less protection for the phone, increasing the risk of damage.

In some embodiments, where protection circuitry is not used, the capacitors may be omitted, however this is less advantageous because the DC voltage that the phone applies between its microphone and ground terminals of its headset jack would be able to flow through the entire circuit of the peripheral device. If the overall equivalent resistance of the peripheral device is lower than that which a phone would recognise as the resistance of a microphone, the phone may not enable the use of the headset jack as a source of data input.

As will already be apparent, the invention is not limited to peripheral devices having any particular structure. The antenna may comprise one or more conducting elements in the form of rigid, flexible, extendable, foldable elements, or at least one of the conducting elements may be in the form of a stub. The antenna, or conducting elements of the antenna, may have a shape and size allowing the antenna to connect to the smartphone in a manner that means the user does not need to interact with the antenna separately to the smartphone, and the combination of smartphone and antenna is not significantly larger than the smartphone alone. This means a user can advantageously keep the antenna connected to the smartphone yet still put the smartphone in their pocket or bag. In some embodiments the antenna may be foldable or telescoping so that the size of the antenna can be increased, extending the range of the antenna, when in use, and then retracted for convenience when not in use. The antenna may have further electronics such as a switch or button to enable or disable the antenna. This may be useful for when the user would like the smartphone to treat the headset jack as empty (e.g. if they would like to make a phone call). This may be accomplished by configuring the peripheral device so that the switch or push button toggles between completing and breaking the circuit between the microphone and ground conductors of the headset jack. Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.