Patent Description:
Smoking articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. Attempts have been made to provide alternatives to these tobacco-burning articles which release compounds from a material without burning. Examples of such products are so-called heat-not-burn products which release compounds by heating, but not burning, the material. The material may be, for example, tobacco or may be a non-tobacco material, which may or may not contain nicotine.

<CIT> discloses a liquid storage portion comprising an electrical component for distinguishing the storage portion from other liquid storage portions. The liquid storage portion is configured for use in an aerosol generating system having means for determining an electrical characteristic of the electrical component and means for distinguishing the liquid storage portion from other liquid storage portions based on the determined electrical characteristic of the electrical component.

<CIT> discloses a control body and cartridge that are coupleable with one another to form an aerosol delivery device. The control body comprises a control component and an RFID reader contained within at least one housing. The cartridge comprises at least one heating element and an RFID tag contained within at least one housing. The RFID reader of the control body is coupled to the control component of the control body and configured to communicate with the RFID tag of the cartridge upon coupling of the control body with the cartridge. The control component of the control body is configured to authorize the cartridge for use with the control body based at least in part on communication between the RFID reader and the RFID tag.

<CIT> discloses an aerosol-generating component of an electrically operated aerosol-generating system, comprising: first and second electrical connection terminals, a first electrical component, the first electrical component being an aerosol-generator, connected between the first and second electrical connection terminals, a second electrical component connected between the first and second electrical connection terminals, a first barrier component connected between the first electrical component and the second electrical connection terminal and a second barrier component connected between the second electrical component and the first electrical connection terminal, wherein the second barrier component has an asymmetric conductance arranged to prevent a current flow through the second electrical component when current is applied to the connection terminals in a first direction (A) but permit a current flow through the second electrical component when current is applied to the connection terminals in a second direction (B), opposite to the first direction, and wherein the first barrier component has an asymmetric conductance arranged to prevent a current flow through the first electrical component when current is applied to the connection terminals in the second direction but permit a current flow through the first electrical component when current is applied to the connection terminals in the first direction.

<CIT> discloses a non-combustion-type flavor inhaler that includes: an atomization assembly including an atomizer configured to atomize an aerosol source without combustion; and a power supply assembly including a power supply for supplying power to the atomizer. The power supply assembly includes: paired electrodes for electrical connection with the atomizer; and a first electrode and a second electrode electrically connected with the power supply. At least one of the first electrode and the second electrode is electrically connectable to a charger for charging the power supply. The non-combustion-type flavor inhaler is provided with a control circuit configured to detect a predetermined current in an opposite direction to a direction of a current flowing through the first electrode or the second electrode when the charger charges the power supply.

<CIT> discloses a fluid vaporization device and related method of vaporization are disclosed. A vaporizable fluid is transported from a fluid reservoir to a vaporization chamber via a wick element which extends into both the fluid reservoir and the vaporization chamber. The fluid in the vaporization chamber is then heated by activating a heating element which is disposed, at least partially, within the vaporization chamber. The heating step transforms the fluid stored in the wick element into a vapor, after which it is transported out of the vaporization device via a conduit.

According to a first aspect of the present invention, there is provided an aerosol generating device for receiving an aerosol generating article, wherein the device comprises an electrical circuit comprising a controller for determining a change in an electrical property of the circuit, and wherein the change is caused by the user interacting with an aerosol generating article received by the device.

The change in the property of the circuit may be caused by the user contacting the aerosol generating article. The article may comprise a conductive material and the change in the circuit may be caused by the user interacting with the conductive material. The change may be caused by the user contacting and thereby electrically grounding the conductive material. The change may be a change in the capacitance of the circuit and the controller may be configured to detect the change in capacitance by detecting a change in the time constant of the circuit. The device may be configured to evaluate a detected change in the property of the circuit to provide an indication of whether the article received in the device is of a predetermined type. The controller may be configured to prevent use of the device when the detected change in property of the circuit indicates that the article received in the device is not an approved article.

According to a second aspect of the present invention, there is provided an aerosol generating article for an aerosol generating device according to the first aspect of the invention, wherein the article comprises a conductive material and the conductive material comprises a first portion for interacting with a user when the user is in contact with the article and a second portion for electromagnetically interacting with the aerosol generating device.

The conductive material may be at least partially arranged at an external surface of the article such that it may be directly contacted by a user. The conductive material may be arranged so that no part of the material is directly contactable by the user.

According to a third aspect of the present invention, there is provided a method of detecting user interaction with an article inserted into a device according to the first aspect of the invention, wherein the method comprises detecting a change in a property of the electrical circuit when a user interacts with the article.

The method may comprise detecting a change in capacitance of the circuit when the user interacts with a conductive material in the article. The method may comprise comparing the change to the property of the circuit to a list of at least one value and enabling the device for use when the change to the property of the circuit corresponds with the at least one value.

Referring to <FIG> there is shown a longitudinal cross-sectional view of an aerosol generating device <NUM>. The aerosol generating device <NUM> has a power compartment <NUM> which houses a power source <NUM> and conducting elements <NUM> for conducting energy through the device <NUM>. In an example, the power source <NUM> is a source of electrical energy, such as a battery, and the power source <NUM> may be, for example, a rechargeable battery or a disposable battery. The conducting elements <NUM> may be wires or the like. The power compartment <NUM> is located towards the distal end <NUM> of the device <NUM> in the example shown in <FIG>.

The device <NUM> has a controller compartment <NUM> which houses a controller <NUM>. The controller <NUM> controls the operation of the device <NUM> based on, for example information received from at least one sensor such as a puff sensor (not shown) located in the device <NUM> or based on requests made by a user of the device <NUM>, for example via user input means <NUM>. The device <NUM> is configured to detect a change in an electrical property of an electrical circuit formed at least in part by the battery <NUM>, the conducting elements <NUM> and the controller <NUM>.

The device <NUM> has an article receiving compartment <NUM> arranged towards a proximal end <NUM> of the device <NUM>. The article receiving compartment <NUM> defines a chamber <NUM> into which an article <NUM> may be received. The article receiving compartment <NUM> comprises a conductive surface <NUM> and a heating element <NUM>. In the example of <FIG>, conductive surface <NUM> is a single plate of conductive material. In other examples, more than one conductive surface, for example more than one conductive plate may be used.

The conductive surface <NUM> is for registering a change in the local environment of the chamber <NUM>. That is, the conductive surface <NUM> is for registering the insertion of an article <NUM> into the chamber <NUM> and registering a change in an electrical property of the article <NUM> when inserted in the chamber <NUM>.

The conductive surface <NUM> is part of the circuit formed at least in part by battery <NUM>, the conductive elements <NUM> and the controller <NUM>. The conductive surface <NUM> is configured to effect a change in an electrical property of the circuit when a change in the local environment of the chamber <NUM> is registered. For example, the conductive surface <NUM> is configured to effect a change in an electrical property of the circuit when the article <NUM> is inserted into the chamber <NUM>. The conductive surface <NUM> is configured to cause a change in an electrical property of the circuit when the user interacts with the article <NUM> when the article <NUM> is inserted in the chamber <NUM>, as will be discussed in more detail below. As such, the circuit formed by the power source <NUM>, the conductive elements <NUM>, the controller <NUM> and the conductive surface <NUM> forms a sensing circuit for sensing the insertion of an article <NUM> and for sensing user interaction with the article <NUM> when inserted in the device <NUM>.

The conductive surface <NUM> is arranged to be affected by a change in the electromagnetic environment near the conductive surface <NUM>. For example, the conductive surface <NUM> may be arranged to be affected by the insertion of conductive material into the chamber <NUM>. When the conductive surface <NUM> is affected by user-related interaction, such as may occur during insertion of the article <NUM> into the chamber <NUM>, the capacitance of the circuit may be affected.

The example article <NUM> shown in <FIG> is elongate in form and has a distal end <NUM> which is inserted into the chamber <NUM> and a proximal end <NUM> which is to be received in the mouth of a user. The article <NUM> has a mouthpiece <NUM> arranged at its proximal end <NUM>. The mouthpiece <NUM> may have a filter or the like for selectively removing elements from the aerosol generated prior to inhalation by the user. In other examples, the article <NUM> may not be elongate in form and may take any suitable form and may, for example, not comprise a mouthpiece <NUM>. The article <NUM> has a conductive material <NUM>, which in this example extends along a length of the article <NUM>. In the example of <FIG>, the conductive material <NUM> extends from the proximal end <NUM> along the majority of the length of the article <NUM>. In other examples, the conductive material <NUM> may extend along any portion of a length of the article <NUM>, for example for only a minority of the length of the article.

The conductive material <NUM> is arranged so that, upon full insertion of the article <NUM> into the device <NUM>, at least a portion of the conductive material <NUM> is arranged to be near to the conductive surface <NUM> of the device <NUM>, such that the conductive material <NUM> can electromagnetically interact with the conductive surface <NUM>.

The conductive surface <NUM> and/or the conductive material <NUM> may comprise any suitable conductive material, for example aluminium, conductive ink, or graphite.

In use, the user inserts the article <NUM> into the chamber <NUM> and at least a portion of the conductive surface <NUM> and conductive material <NUM> are arranged in a proximity to one another such that they may electromagnetically interact with one another. When arranged at such a proximity to one another, the first conductive surface <NUM> and the second conductive surface <NUM> may together have a first capacitance C0.

When the user contacts the article <NUM> received in the device <NUM> the user changes a property of the circuit. For example, the capacitance of the circuit may be changed by user interaction with the article <NUM>. The change may be caused by the user contacting the conductive material <NUM> in the article <NUM>, and thereby acting to electrically ground the article <NUM>, or by the user otherwise interacting with the conductive material <NUM> such as deforming it through holding the article <NUM>, or by a capacitive coupling effect between the user and the conductive material <NUM> of the article. The interaction of the user with the conductive material <NUM> may act to change the capacitance of circuit due to changing the capacitance at the conductive surface <NUM> and conductive material <NUM>, for example to a second capacitance value C2. The change in capacitance from C0 to C2 may be detected by the controller <NUM>.

Utilising the effect of a user interacting with an article received by the device <NUM> may allow for a relatively large change in the electrical property of the circuit to be produced. For example, a relatively small change in capacitance in the circuit may be produced by insertion of an article which is not significantly affected by user interaction. In examples described herein, the user's interaction with the article <NUM> may amplify the change in the electrical property produced in the electrical circuit. For example, by grounding the conductive material <NUM> or producing a capacitance coupling between the user and the article <NUM>, a larger change in the capacitance of the circuit may be produced than that produced by insertion of an article which is not affected by user interaction. The larger magnitude of the change may allow more reliable detection. In turn, this may allow the controller <NUM> to more accurately determine a property of the article <NUM>, for example by providing a more reliable value for comparison to a list of pre-determined values, as will be described below.

The controller <NUM> may compare a detected change in capacitance when an article <NUM> is inserted with a database of capacitance values. In this way, the controller <NUM> may obtain an indication of whether the inserted article <NUM> is of a predetermined type. For example, the controller <NUM> may determine whether the article <NUM> is an article which is approved for use with the device <NUM> by the manufacturer by comparing the change in capacitance to a detected first capacitance C0 with a list of predetermined capacitance values which are associated with approved articles. If the detected capacitance matches a value from the list of predetermined values then the controller <NUM> may determine that the article <NUM> is approved for use and may be configured to enable use of the device <NUM>. In preferred examples, the controller <NUM> may be configured to prevent use of the device <NUM> when the detected capacitance indicates that the article <NUM> is not approved for use.

As mentioned above, the controller <NUM> is also configured to detect a change in the capacitance of the conductive surface <NUM> and the conductive material <NUM> to a second capacitance value C2 due to a user interacting with the conductive material <NUM>. The detected change in capacitance may be used to provide an indication of the type of article <NUM> inserted into the device <NUM> by comparing to a database of capacitance values, as described in the preceding paragraph. The change in capacitance of the circuit due to user interaction with an article <NUM> inserted in the device, in preferred examples, is used to determine whether an article <NUM> is of a predetermined type, for example, whether the article <NUM> is one which is approved for use by the manufacturer of the device <NUM>. The device <NUM> may be enabled or not enabled, depending on whether an inserted article <NUM> is determined to be approved or not.

In some implementations, articles that have different aerosolisable material (i.e., material providing different flavoured aerosols or different strengths of flavour/active substances) may be provided with different conductive materials that effect the properties of the electronic circuitry in different ways when a user interacts with the article <NUM>. For example, a change in capacitance by a certain first amount may be indicative of one flavour of aerosolisable material, whereas a change in capacitance by a certain second amount may be indicative of another flavour of aerosolisable material. The controller <NUM> may be configured to not only detect a change in capacitance but also to quantify a change in capacitance and associate the change with a given article <NUM>. The controller <NUM> may take enable the device to take different actions based on the magnitude of the change in capacitance.

In some examples, the device <NUM> may detect the length of time that a user is in contact with the article <NUM> while it is inserted in the device <NUM> via detection of a change in capacitance. The device <NUM> may, in some examples, detect a location at which the article <NUM> has been contacted by a user by measuring a change in capacitance and comparing to a reference value. In some examples, the device <NUM> may infer the duration of a puff by a user by detecting contact with the user's lips and the duration of such contact.

Once the device <NUM> is enabled, the controller <NUM> may instruct the power source <NUM> to provide energy to the heating element <NUM>. The heating element <NUM> may be a resistive, chemical or inductive heater or the like. Activation of the heating element <NUM> may be based on the detection of the initiation of a smoking session by a puff sensor in the device <NUM>. Alternatively, the user may select activation of the heating element <NUM> via an interface <NUM> on the device <NUM> after the device <NUM> has entered the operational state. The user may be informed via the interface <NUM> on the device <NUM> that the device <NUM> has entered the operational state.

In some examples, a detected change in capacitance may be used to provide an indication that a user is in contact with the article <NUM>, and may act to indicate that the user is using the device <NUM>. For example, an indication of use of the device <NUM> by the user may be used by the controller <NUM> to keep the device <NUM> in operation, and the controller <NUM> may be configured to change a factor of the operation of the device <NUM> when use of the device <NUM> (through a detected change of capacitance) has not been detected for a predetermined length of time. For example, the controller <NUM> may be configured to deactivate the device <NUM> when it detects that a user has not contacted the article <NUM> for a time period such as <NUM> minutes, or <NUM> minute.

The device <NUM> may require that a change in capacitance which is associated with when an approved article is contacted by a user is detected at regular intervals to keep the device <NUM> in operation. The device <NUM> may be enabled for the typical time required for a smoking session. In an example, the device <NUM> is enabled for around <NUM> minutes. In an alternative example, the device <NUM> is enabled for a shorter time. An advantage associated with enabling the device <NUM> for a shorter time period is that if attempts to circumvent the prevention features of the device <NUM> have led to the device <NUM> being enabled despite use of a non-approved article, such attempts would need to be repeated throughout the smoking session. This would make circumventing the prevention features of the device <NUM> more cumbersome for any person attempting to do so.

In other examples, the change in capacitance to C2 may act as a wake-up signal for the device. For example, the device may be provided nominally at a low power state (either by default or via activation of a hard on/switch, e.g., a user actuatable button provided on a surface of the device). In the low power state, the functions of the device may be limited, but the controller <NUM> is configured to detect changes in capacitance. As a user inserts the article <NUM> into the device, they contact the article <NUM> and thus couple the article to ground. Accordingly, when the article <NUM> is fully inserted, the capacitance C2 is detected by the controller <NUM>. The controller <NUM> is configured, upon detecting the capacitance C2 for the first time, is configured to transition the device from a low power to a higher power state (i.e., a state in which functions of the device are not restricted). For instance, this might cause power to be supplied to the heater, or it might cause power to be supplied to a display screen on the device. In this way, the device can transition from a low power to a high-power state based on detection of a certain capacitance value indicative of the user interacting with the article <NUM>.

Examples of articles <NUM> for use with the device <NUM> of <FIG> are shown in <FIG>. The article <NUM> shown in <FIG> has a distal end <NUM> for insertion into the device <NUM> of <FIG> and a proximal end <NUM> with a mouthpiece <NUM> for insertion into the mouth of a user. The conductive material <NUM> has a number of connected portions 532a, 532b, 532c.

The first portion 532a of the conductive material <NUM> is arranged at the proximal end <NUM> of the article <NUM>. The first portion 532a is located near the mouthpiece <NUM> and may surround a portion of the mouthpiece <NUM>. The first portion 532a is arranged so that the user may interact with the surface when holding the article <NUM> in the fingers or in the mouth during use. The first portion 532a registers the interaction of the user with the article <NUM> and a change is detected by the controller <NUM>.

The first portion 532a is connected to a second portion 532b of the conductive material <NUM>. The second portion 532b is a connecting portion between the first portion 532a and the third portion 532c of the conductive material <NUM>. The second portion 532b is thinner than the first portion 532a and third portion 532c in the example shown in <FIG>. The second portion 532b pervades any changes to the first portion 532a through to the third portion 532c.

The third portion 532c is arranged in a location to be within a proximity of the conductive surface <NUM> of the device <NUM>. This may be towards the centre of the article <NUM> or towards the distal end <NUM> of the article <NUM>. The third portion 532c is of a size such that electrical changes to the first portion 532a are transmitted clearly to the first conductive surface <NUM> of the device <NUM>.

Each portion of the conductive material <NUM> of the article <NUM> can be located either internally or externally of the article <NUM>, for example a portion such as the third portion 532c may be located internally of the article <NUM> and may be circumscribed by an outer layer of the article <NUM> such as a paper outer layer. Whether portions of the conductive material <NUM> are located internally of externally may impact the clarity of signal transmitted to the circuit of the device <NUM>, with externally located conductive material <NUM> generally having better clarity of signal. The clarity of signal to the circuit of the device <NUM> may also be affected by the size or area of the various portions of the conductive material <NUM>. In examples where the conductive material <NUM> is on an external surface of the article <NUM> the area of conductive material <NUM> may be reduced in comparison to an arrangement wherein the conductive material <NUM> is internal to the article <NUM> while maintaining a comparable signal clarity.

In examples where the conductive material <NUM> is configured to be directly contacted by a user, the first portion 532a should not be so small that the user may hold and use the article <NUM> without contacting the conductive material <NUM>. In the example shown in <FIG>, the first portion 532a is external but the second and third portions 532b, 532c are internal.

Referring now to <FIG>, there is shown an example of an article <NUM> for use with the device <NUM> of <FIG>. The article <NUM> shown in <FIG> has similar features to the article <NUM> shown in <FIG>. Where features are broadly the same across examples, the same reference numerals have been used and the description will not be repeated.

All three portions 532a, 532b, 532c of the conductive material <NUM> are internal in the example shown in <FIG>. As mentioned above, the first portion 532a of the article <NUM> in <FIG> needs to be larger in area than that first portion 532a of the article <NUM> in <FIG> to provide the same signal clarity. Where there is no direct contact between a user and the conductive portion <NUM>, for example because the section of the conductive portion 532a is located internally, as in <FIG>, detection of user interaction by the conductive portion may be achieved by a capacitive coupling between due the user and the conductive portion <NUM>. The internal placement of the first portion 532a in the example of <FIG> is likely to be more desirable from the user's perspective as the article <NUM> will have the appearance of a normal consumable. Further, the user will likely more preferably touch a mouthpiece with a "normal appearance" with their lips rather than one with conductive material surrounding the mouthpiece. The conductive material <NUM> being placed internally, such as in this example, may also contribute to mitigating electrical noise picked up by the conductive material.

Referring now to <FIG>, there is shown an example of an article <NUM> for use with the device <NUM> of <FIG>. All three portions 532a, 532b, 532c of the conductive material <NUM> are externally located in the example shown in <FIG>. As mentioned above, locating the conductive surface <NUM> on an external surface of the article <NUM> improves the signal quality for a comparably sized conductive material <NUM>. This can enable a manufacturer to use less conductive material while still maintaining an acceptable amount of signal during use. The conductive material <NUM> may be incorporated into an aesthetic element such as design to provide a visually pleasing effect for the user.

Referring now to <FIG>, there is shown an example of an article <NUM> for use with the device <NUM> of <FIG>. The conductive surface <NUM> comprises a continuous body rather than a number of portions with distinct sizes or widths as in previous examples. The continuous body is made of a proximal portion 532a, a middle portion 532b and a distal portion 532c and may be arranged on an external surface of the article <NUM> or arranged internally, for example beneath a paper layer on the outer of the article <NUM>. Where arranged internally a greater area of conductive surface <NUM> is required to be used to provide an appropriate signal strength to where the conductive material <NUM> is arranged externally. However, as mentioned above, the internal arrangement may be more visually pleasing for a user. This construction may have several manufacturing advantages as less complex patterns of conductive surfaces need to be provided.

A rod may be heated fairly evenly via heaters <NUM> that are arranged externally to the rod, such as in the device <NUM> shown in <FIG>. Alternatively, the article <NUM> may be of any shape corresponding to the cavity <NUM> of the device <NUM> with which the article <NUM> is to be used. The only restriction on the shape of the article <NUM> is that the article <NUM> should, in use, project from the user to a suitable proximity to the conductive surface <NUM> in the device <NUM> so that the conductive material <NUM> may affect the conductive surface <NUM>.

It should also be appreciated that the conductive surfaces described above do not need to be formed in continuous loops, i.e., they do not need to electrically connect in the circumferential direction of the articles <NUM>. For instance, the conductive surfaces may form partial loops around the outer surface of the article, and define a gap between ends of the conductive surface (e.g., in a horse-shoe type arrangement). However, increasing the angular extent of the conductive surfaces around the surface of the article <NUM> (or within the article <NUM> in the case the conductive surface is not on an external surface of the article <NUM>) may be advantageous in permitting a good conductive coupling however the user holds the article <NUM>.

Referring now to <FIG>, there is shown an example of the article <NUM> in use in a device <NUM>. To improve the cleanliness of the signal detected by the controller <NUM>, suitable materials may be chosen for an outer wall <NUM> of the device <NUM>. For example, the outer wall <NUM> could be a conductive material which is connected to the circuit and used to ground the circuit when a user contacts the outer wall <NUM>. The conductive surface <NUM> may be backed by an insulating material (not shown) in order to improve reliability of the sensing circuit <NUM>. An electrically grounded component (not shown) may be located adjacent a side of the insulating material facing away from the conductive surface <NUM>, and such a component may be grounded by, for example, connection to a conductive outer wall <NUM> of the device <NUM>.

Referring now to <FIG>, an example circuit <NUM> for use in the device <NUM> will be described. The circuit <NUM> has a number of features shown previously in <FIG>. Similar features are shown with numerals increased by <NUM> and discussion of these features will not be repeated here.

The circuit <NUM> shown in <FIG> has a controller <NUM> for registering a change in an electrical property of the circuit <NUM>, a conductive surface <NUM> through which a change in an electrical property of the circuit <NUM> may be affected and conductive elements <NUM> for connecting the controller <NUM> to the conductive surface <NUM>. The controller <NUM> may be a microcontroller or a microprocessor or a timing circuit, which may in some examples be an analogue timing circuit.

The controller <NUM> has two connection points to the conductive elements <NUM>: a first connection point P1 and a second connection point P2. The circuit <NUM> also has a resistor R1 arranged between the conductive surface <NUM> and the first connection point P1 to the controller <NUM>. Optionally the circuit <NUM> may also have, shown in grey in <FIG>, a capacitor C1 and an electrical ground <NUM>. Inclusion of the capacitor C1 in the circuit may improve the reliability of the circuit <NUM> and improve the stability and repeatability of readings provided by the circuit <NUM>.

The controller <NUM> is able to detect a change in an electrical property of the circuit <NUM> by toggling a state of first connection point P1 and measuring the time taken for the second connection point P2 to register the changed state. The time taken for this to occur is determined by a time constant that is related to the resistance of resistor R1 and the capacitance of the circuit <NUM>. The circuit <NUM> is therefore able to detect a change in capacitance of the circuit by detecting a change in the time constant of the circuit.

The capacitance of the circuit <NUM> includes the capacitance of capacitor C1 (if present) and any additional capacitance present at the conductive surface <NUM>, such as that which exists when a conductive material <NUM> is placed in close proximity with the conductive surface <NUM>. As discussed above, interaction of a user with the conductive material <NUM> changes the capacitance at the conductive surface <NUM> and the conductive material <NUM>.

A change in capacitance for example (a change to C0) due to insertion of an article <NUM> or for example (a change to C2) due to user interaction with the conductive material <NUM> is therefore detected by controller <NUM> as a change in the time constant of the circuit <NUM>. That is, a change in capacitance due to insertion of an article <NUM> or user interaction with the conductive material <NUM> (such as by contact with the article <NUM> by the fingers of mouth of the user) alters the time taken for the second connection point P2 to register a change in state. The controller <NUM> may note the time taken and can compare it to a database of time periods, which the controller <NUM> may comprise or which may be provided as a separate component of the circuit <NUM>. Values in the database may, for example, represent pre-determined time periods associated with approved articles for use with the device <NUM>. When the time period taken for the state change to be registered is equal, within some pre-determined acceptable boundaries, to a pre-determined time period, the controller <NUM> has received an indication that the received article <NUM> is approved and may enable the device <NUM>.

The controller <NUM> may control the toggling of first connection point P1. Toggling may occur prior to the beginning of a usage session, or the controller <NUM> may toggle the first connection point P1 after a set interval. The controller <NUM> may be configured to toggle the state of first connection point P1 periodically throughout a usage session. For example, the controller <NUM> may continue to periodically toggle the state of the first connection point P1 while a puff detector continues to detect that the device <NUM> is in use. The controller <NUM> may initially toggle upon request from a user, following insertion of an article <NUM> into the device <NUM> in which the circuit <NUM> is housed, and then at various intervals during the usage session to ensure an approved consumable is being used throughout the usage session. This would prevent activation of the device <NUM> by an approved consumable which is subsequently replaced in the device <NUM> by an article which is not approved.

Claim 1:
An aerosol generating device (<NUM>) for receiving an aerosol generating article (<NUM>) in a chamber (<NUM>) of the aerosol generating device, wherein the device comprises an electrical circuit (<NUM>) comprising a controller (<NUM>) for determining a change in an electrical property of the circuit, wherein the change is caused by a user interacting with an aerosol generating article received by the device and the electrical property is capacitance, conducting elements (<NUM>) for conducting energy through the device, and a conductive surface (<NUM>), wherein the controller is configured to evaluate a detected change in the property of the circuit to provide an indication of whether the article received in the device is of a predetermined type, whereby the electrical circuit formed by the power source, the conductive elements, the controller and the conductive surface forms a sensing circuit for sensing the insertion of the article based on a change in the electromagnetic environment near the conductive surface caused by the insertion of conductive material into the chamber.