WO2014049086A1

WO2014049086A1 - Event recording device

Info

Publication number: WO2014049086A1
Application number: PCT/EP2013/070126
Authority: WO
Inventors: Florin STROIESCU; Seamus Donnelly
Original assignee: Realtime Technologies Limited; University College Dublin National University Of Ireland, Dublin
Priority date: 2012-09-27
Filing date: 2013-09-26
Publication date: 2014-04-03
Also published as: GB2506385A; GB201217291D0

Abstract

An event recordal device (104, 301) for an inhaler (100), comprising a sensor (308), an antenna (310, 403) and a switching circuit (404), wherein the sensor (308) is arranged to (308) sense an actuation event; the antenna (310, 403) is configured to receive a query from a remote reader (302) and transmit a modulated response indicative of the query and at least one sensed event to the reader in response to the received query; and the switching circuit (404) is arranged to modulate the response during transmission from the antenna.

Description

EVENT RECORDING DEVICE

Field of the Invention

[0001] The present invention relates to an event recordal device and in particular an event recordal device for medicinal dispensers such as respiratory inhalers.

Background to the Invention

[0002] The dispensing of medication to the respiratory systems of patients, particularly those with illnesses such as COPD, asthma, or other types of influenza is typically implemented using respiratory inhalers. Commonly, these inhalers are built as metered dose inhalers (MDI). MDIs generally store the medication in a pressurized canister containing a propellant or suspension. When activated the MDI releases a fixed quantity of medication.

[0003] In order to ensure the correct dosage, a clinician generally prescribes the time and number of actuations and/or releases (puffs). In most of the cases, the correct usage is crucial for the correct treatment. As the usage of the dispenser is normally remote from the clinical environment, there is a significant scope for user error for example, dispensing at the incorrect time, or incorrect actuation of the device.

[0004] MDI devices are available which record the time of actuation of the MDI for later retrieval. This facilitates the analysis of the patterns of usage so that a medical professional can make correct decisions regarding the treatment of a patient. Mechanical or electronic counters are in standard use to provide such a recordal device, however this is a crude indication of the number of actuations. In addition, this counter is often used as an indicator for the depletion of the medication in the MDI. Inaccurate recordals from such devices can also lead to inaccurate depletion information and accordingly surplus or insufficient medication in the canister.

[0005] There is a need for a MDI device that can provide accurate information regarding the usage patterns and times of the usage, in order to assist the doctors to correctly asses and plan the further treatment.

[0006] It is further desirable to provide means for transferring the recorded data from the MDI. Radio-frequency identification devices, RFID, systems are wireless non-contact systems that use radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for the purposes of automatic identification and tracking. RFID devices are designed to work with very low power consumption on the tag side. RFID is a wireless non-contact system that uses radio-frequency electromagnetic fields to transfer data from a tag attached to an object. However, FID systems are capable of transferring only fixed or pre-recorded static data. This data may include a serial number or product related information such as a stock number, lot or batch number, production date or other specific information. This information is recorded once for every tag and is static between the initial recordal and receiver scanning. It is therefore desirable to provide a communication mechanism capable or receiving interrogation queries and producing characteristic answers and engaging in dialogue with a receiver to transmit these characteristic answers. It is also desirable to provide a mechanism for the transmission of variable answers according to the queries received and data stored. It is also desirable to enable the memory erasing, initialisation or other actions on the tag side as a result of specific queries received from a receiver such as a reader or dock.

[0007] While the above listed features are desirable, it is necessary to maintain the compact size of dispensing devices. It is also desirable to minimize the need for regulatory approval which would increase the costs associated with the device. Therefore it is necessary that any device recording the usage patterns and time of usage have minimal power requirements to mitigate the need for larger power sources or complex circuitry and additional cost.

[0008] The present invention provides a low power device suitable for use by patients with pulmonary diseases as a means to deliver medication to the respiratory system, while accurately recording information representative of the delivery allowing the accuracy of the treatment to be verified. These features are achieved with minimal power requirement.

Summary of the Invention

[0009] In one aspect, the present invention provides a event recordal device for an inhaler, comprising

a sensor, an antenna, and a switching circuit, wherein

the sensor is arranged to sense an actuation event;

the antenna is configured to receive a query from a remote reader and transmit a modulated response indicative of at least one sensed event and the received query to the reader in response to the received query; and

the switching circuit is arranged to modulate the response during transmission from the antenna.

[0010] The use of the switching circuit to modulate the response provides a simple low cost and low power means for transmitting recorded data indicative of actuation events of an inhaler. Variable answers may be transmitted as the response is indicative of the query and also the sensed event. As the antenna is in communication with the remote reader it is engaged in communication and therefore can transmit characteristic answers to the reader.

[0011] An actuation event may include an actuation of the inhaler. By depressing the canister in a metered dose inhaler, an actuation occurs. This can be sensed by the event recordal device as an actuation event.

[0012] The switching circuit may be arranged to short a first node and a second node of the antenna to modulate the response. By modulating the response varying communications comprising information which is in direct response to the query and so customised in response to the query can be transmitted.

[0013] The switching circuit may comprise a switch configured to short the first node and the second node by alternating between an open and a closed state. This simple switching mechanism has a minimal power requirement, thereby maximising the battery life in battery operated MDI.

[0014] The switching circuit may be arranged to short the first node and second node in a sequence indicative of the sensed event. By shorting the first node and second node in a sequence varying and variable information can be transmitted and received by the event recordal device.

[0015] The antenna may comprise a coil. The first node may be a first end of the coil and the second node may be an opposing end of the coil. This provides a simple and low cost structure.

[0016] The switch may comprise a metal oxide semiconductor field effect transistor, MOSFET. These are low cost components.

[0017] The event recordal device may further comprise a clock unit for determining a time stamp corresponding to the sensed event.

[0018] The response indicative of the sensed event may include the time stamp for the sensed event.

[0019] The time stamp may include the time and date of the sensed event.

[0020] The modulated response may be further based on a determined characteristic of the event.

[0021] The time stamp may be offset to an activation time of the event recordal device. By having a time stamp offset to the activation time rather than a global clock it is not necessary to have a MDI which is correctly synchronised to a global clock. Any discrepancies due to drift may be accounted for. In addition, the MDI does not need to be activated while in storage and therefore the battery life is maximised as the MDI is only activated when needed. [0022] The response indicative of the sensed event may include the activation time of the event recordal device. The activation time of the event recordal device may be stored in the memory unit of the event recordal device. The activation time may be zero hours, zero minutes and zero seconds. The activation time may further comprise an activation date of the event recordal device. Recording the activation time allows for the corrected time and date of an actuation event to be calculated.

[0023] The event recordal device may further comprise a power supply circuit. The event recordal device may further comprise means for activating the power supply circuit. The power supply circuit may comprise a battery. The means activating the power supply circuit comprises a seal arranged to inhibit electrical connection to the battery and wherein activating the power supply circuit comprises removing the seal. This ensures that the battery is not depleting in storage.

[0024] The event recordal device may further comprise an actuator for generating the event. The actuator may be selected from the list including a magnetic, a light or a movement actuator.

[0025] The event recordal device may further comprise a microcontroller unit, MCU in communication with the sensor. The event recordal device may further comprise an algorithmic state machine. The MCU may be configured to perform integrity checks on the sensed event. The MCU may be configured to filter the sensed event. The MCU may be configured to obtain the time stamp from the clock unit. The event recordal device may further comprise a memory in communication with the MCU and configured to store the time stamp. The memory may be non-volatile memory.

[0026] The MCU may be further arranged to initiate modulated transmission from the antenna to the reader in response to an excitation signal induced by the reader in the antenna. The MCU may be configured to periodically determine whether an excitation signal has been induced by the reader in the antenna. The MCU may be arranged to cooperate with the switching circuit to short the first and second node. The event recordal device according to any previous claim further comprising a user interface. The user interface may comprise a connector.

[0027] A further embodiment of the present invention includes an inhaler comprising the event recordal device as described above.

[0028] A further embodiment of the present invention includes a reader for use with the event recordal device as described above comprising:

a receiver for receiving a modulated response from the event recordal device; an excitation means arranged to induce an alternating excitation signal in the antenna of the event recordal device and the receiver wherein the excitation means is further configured to modulate the alternating excitation signal to communicate a query to the event recordal device.

[0029] As the reader excites the antenna in the event recordal device, the power requirement at the event recordal device is further minimised.

[0030] The query may be encoded using amplitude shift keying, ASK.

[0031] The reader may further comprise a microcontroller unit, MCU for processing the received response from the event recordal device. The received response may include a time stamp for an actuation event, the time stamp being offset to an activation time of the event recordal device.

[0032] Processing the received response may comprise

querying the event recordal device to obtain a time stamp corresponding to the time of calculating;

querying an external device to determine the correct time of calculating; determining the difference between the correct time and the obtained time stamp corresponding to the time of calculating; and

correcting the time stamp for the actuation event based on the determined difference.

[0033] Processing the received response may further comprise querying the event recordal device to obtain an activation time of the event recordal device. The external device comprises a personal computing device. The alternating excitation signal is permanent or periodic.

[0034] The reader may further comprise means for communicating with at least one of a personal computing device or the worldwide web.

[0035] A system comprising an event recordal device and a reader as described above.

[0036] The system may further comprise a personal computing device.

[0037] The present invention also includes a method of operating an event recordal device, comprising sensing an actuation event; receiving a query from a remote reader; and transmitting a modulated response indicative of the query and at least one sensed event and to the reader.

[0038] The method may further comprise shorting a first node and a second node of an antenna to modulate the response during transmission.

[0039] The first node and second node may be shorted in a sequence indicative of the sensed event. The above described method may further comprise determining a time stamp corresponding to the sensed event. The method may further comprise storing the determined time stamp. The time stamp may include the time and date of the sensed event. The time stamp may be offset to an activation time of the event recordal device. The sensed event may include the activation time of the event recordal device. The activation time may further comprise an activation date of the event recordal device.

[0040] The method described above may further comprise performing at least one of integrity checks or filtering.

[0041] The method described above may further comprise initiating transmission of the modulated response in response to an excitation signal induced by the reader in an antenna of the event recordal device.

[0042] The method may further comprise periodically determining whether an excitation signal has been induced.

[0043] A further embodiment of the present invention includes a method of correcting a time stamp for an actuation event, comprising:

querying an event recordal device to obtain a time stamp corresponding to the time of processing;

determine the time of the query;

determining the difference between the time of the query and the obtained time stamp corresponding to the time of processing;

[0044] The method may further comprise querying the event recordal device to obtain an activation time of the event recordal device.

[0045] The method may further comprise determining a corrected start time of the event recordal device based on the activation time of the event recordal device, wherein determining the corrected start time may comprise determining the difference between the obtained time stamp corresponding to the time of processing and the activation time and subtracting the difference from the time of the query.

[0046] Correcting the time stamp is further based on the corrected start time

[0047] Brief Description of the Drawings

[0048] Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings in which:

[0049] Figure 1 is a conventional metered dose inhaler including an event recordal device in accordance with the present invention;

[0050] Figure 2 is a side profile view of an event recordal device in accordance with the present invention. [0051] Figure 3 is a block diagram of a system incorporating the event recordal device of Figure 2 and a reader for communication with the event recordal device in accordance with the present invention.

[0052] Figure 4 is a simplified view of a low power communication mechanism in accordance with the present invention.

[0053] Figure 5 is a flow chart detailing an example of the method as implemented on the event recordal device in accordance with the present invention.

[0054] Figure 6 is a switching schematic for the switching mechanism of the low power communication mechanism in accordance with the present invention.

[0055] Figure 7 is a simplified view of the schematic of figure 6 when the switching mechanism is receiving information in accordance with the present invention.

[0056] Figure 8 A and B are simplified views of the schematic of figure 6 when transmitting information in accordance with the present invention.

[0057] Figure 9 is a flow chart directed to a method of calculation of the time of actuation of the event recordal device in accordance with the present invention where the device time has not been initialised.

[0058] Figure 10 is a flow chart directed to an alternative method of calculation of the time of actuation of the event recordal device in accordance with the present invention where the device time has not been initialised.

Detailed Description of the Drawings

[0059] The inhaler 100 as shown in figure 1, is a conventional metered dose inhaler 100, fitted with a mechanical counter 105 and including a pressurised canister 103. The pressurised canister contains the medication to be dispensed either as a propellant or a suspension.

[0060] Applying pressure to the canister 103 actuates the device and causes the medication to be dispersed through the mouth piece 102.

[0061] The inhaler 100 has been modified to include an event recordal device 104 in accordance with the present invention. As shown in figure 1 the event recordal device is inserted into the conventional inhaler 100 as an add-on device or module. The small footprint of the event recordal device allows conventional inhalers to be used with no modifications. The separate add-on event recordal device as shown in Figure 1 allows event recordal devices as described herein to be reusable. It will be appreciated that the event recordal device may be integral to a metered dose inhaler. The event recordal device may be included at time of manufacture of the metered dose inhaler. [0062] Figure 2 shows further detail of the event recordal device 104 of figure 1. The event recordal device 104 has a slim profile substantially rectangular body 201. The recordal device is preferably medically compatible, non-toxic and non-metallic. It will be appreciated that a metallic unit would lead to transmission interference. An actuator 202 is located on the body 201 of the event recordal device 104. In figure 2, the actuator 202 is an electro-mechanical actuator and is selected to be suitable for use with the MDI of figure 1. When the canister 103 of figure 1 is depressed the actuator located on the underside of the event recordal device 202 is actuated by pressure applied by the body 101 of the inhaler as the canister 103 is pumped or depressed. An optional user interface 203 is also provided to allow user access to the information contained on the event recordal device or to allow updating of the firmware of the device.

[0063] In normal use the event recordal device is part of the MDI of Figure 1. However, when returned to a clinical environment the event recordal device can be interrogated. In one configuration the event recordal device can be removed from the MDI for interrogation. Alternatively, the interrogation can take place with the device in situ in the MDI. The data from the event recordal device is transferred to a personal computing device such as a PC, tablet computer, smart phone or other device as shown in the system of figure 3. The system 300 of figure 3 includes a reader or dock 302, in communication with a personal computing device 303, and an event recordal device 301 in accordance with the present invention. The reader may be a docking station in which the event recordal device alone or the MDI incorporating the event recordal device is mounted. Alternatively, the reader may be a proximity reader or other near field communication device.

[0064] The event recordal device 301 includes an actuator module 304, a battery module 305 a real time clock calendar module or clock unit 306, a microcontroller unit, MCU, 307, a sensor 308, a memory block 309 and a communication module 310 in communication with a coil 311. The sensor module 308 can be arrange to sense magnetic, optical or electromagnetic acutuations as outlined in relation to figure 2. When in use and in range of the reader 302 the event recordal device signals it's presence. In turn, the reader initiates the communication with the event recordal device. The reader comprises a communication module 313 and a microcontroller 314. The communication module 313 is arranged to transmit the data to the personal computing device 303 and the event recordal device using the coil 312.

[0065] The event recordal device is a necessarily low power device as it needs to be able to function over a long period of time from a low capacity battery. The size and correspondingly the capacity of the battery is constrained by the footprint of the event recordal device. If the actuator 304 has been actuated, the event recordal device 301 then records the date and time of the event in the memory. If a dock has been sensed a communication session is initiated and data is transferred from the personal computing device 303 via the reader 302.

[0066] The event recordal device 301 in accordance with the present invention is arranged to permit the reception of interrogation queries from the reader 302. In response the event recordal device produces characteristic answers and engages in a dialogue between the reader and the event recordal device. The event recordal device is arranged to transmit variable answers according to the received queries and the information stored in the internal memory at the time of actuation. The event recordal device is also arranged to perform memory erasure, initialisation of identification data as a result of the specific queries received from the receiver.

[0067] When the event recordal device 301 is started or activated for the first time, 501 as outlined in figure 5, the real time clock calendar or clock unit 306 is initialised, 502 as shown in figures 9 and 10. It will be appreciated that starting or activating for the first time also includes re-starting or re-activating following the replacement of a power source such as a battery.

[0068] The event recordal device 301 is then configured to wait for a predefined period of time. This predefined period of time may be three seconds, five seconds, or any suitable period of time to allow for multiple accidental actuation. In the preferred low power configuration, the device is maintained in a power down status following initialisation of the clock unit 306, awaking only periodically to check the status of the actuator 304 and also whether a reader or dock 302 is in the vicinity of the event recordal device. When the reader 302 or dock is in the vicinity of the event recordal device it is in range for communication with the event recordal device.

[0069] The configuration outlined in figure 5 outlines this period as twice per second or every 0.5 seconds. The event recordal device 301 wakes for a predefined period of time, normally less than one millisecond. The sensor 308 then determines whether an actuation has occurred, 504. When an actuation occurs 504 the sensor 308 detects an actuation and communicates to them microcontroller 307.

[0070] If an actuation has occurred, the sensor 308 instructs the microcontroller 307 to interrogate or read 506, the clock unit 306 to obtain the time and date offset to the initialised time of the clock unit as initialised at step 502. The event is then stored, 507 in the memory 309 of the device for subsequent retrieval.

[0071] The memory 309 is preferably non-volatile memory. The microcontroller 307 may also perform filtering and integrity checking on the retrieved event prior to storing. [0072] The device 301 then returns to a low power or sleep mode, waking periodically as indicated in step 503.

[0073] If no actuation has occurred, the microcontroller 307 determines 505 whether a reader is in the vicinity or range of the event recordal device. To sense the presence of a reader, the microcontroller 307 determines whether a voltage has been induced in the antenna or coil 311 by an excitation coil 312 of the reader 302. If an induced voltage is sensed, the microcontroller, 307 issues an instruction to the communication module 310 to initiate signalling and communication, 508. The signalling and communication step is used to transfer data to the reader as explained further below.

[0074] The microcontroller 307 is also configured to determine whether the event recordal device 301 is in a transfer mode. In transfer mode the event recordal device can communicate with the reader 302, sending a response to a query to the reader. If the device is ready to transfer 510, data is transferred to the reader 302. If the event recordal device is not ready to transfer, then the device remains in the transfer data state 509.

[0075] Signalling and communication from the event recordal device 301 to the reader 302 is carried out by shorting the ends of the coil 311, in sequence. This translates to a reduction of voltage over the reader coil 312. The reader coil 312 is continuously monitored by a reader microcontroller unit 314 for voltage reduction corresponding to a communication from the event recordal device. Communication from the reader 302 is done by modulating the amplitude of an excitation signal generated at the coil 312.

[0076] In one configuration as shown in Figure 4 the reader coil 312 comprises an excitation coil 402 and a receive coil 401. The excitation coil in the reader 402 permanently or periodically oscillates. This oscillation induces a voltage in the receive coil 401 of the reader and when in range, a receive/transmit coil 403 in the event recordal device. The receive/transmit coil 403 in the event recordal device senses the presence of the reader when a voltage is induced across the coil. The receive transmit coil 403 also signals the presence of the event recordal device to the reader. The receive/transmit coil also receives interrogation or queries from the reader and transmits the stored data to the reader.

[0077] Communications from the reader are encoded using amplitude shift keying ASK protocol, however it will be appreciated that any industry standard communication can be used with the correct communication interface. As described below, the communication in accordance with the present invention is short range and slow but power efficient as the only energy used for transmission is for shorting the switch. Switching as proposed in the present application is implemented as shown in figures 6 to 8 with low power MOSFET transistors or gates.

[0078] ASK is used with synchronisation characters at the start of each transmission. Use of ASK modulates the carrier frequency. For bit symbols encoding used is non return to zero inverted (N ZI) however it will be appreciated that the present invention is not restricted as such.

[0079] The receive/transmit coil 403 includes a switching mechanism 404 for controlling communication to and from the event recordal device. Figure 6 outlines a suitable switching schematic for a switching and receiving mechanism in accordance with the invention. Of particular significance is the inclusion of internal protection diodes or parasitic diodes 601,602 in the MOS transistors Ql and Q2.

[0080] When configured to receive information the transistors Ql and Q2 behave as shown in Figure 7. The transistors Ql and Q2 are shown as simple switches for ease of explanation.

[0081] While awaiting the receipt of a signal, switch Ql is closed and switch Q2 is opened. Diode D and the protection diode 601 create a detector circuit for detection of a signal sent by the receiver/reader. As outlined above the event recordal device checks for a voltage induced by the excitation coil of the reader. Once this is detected, the data signal is received at point 1 and is processed by the communication module 310 and the microcontroller unit 307.

[0082] In the circuit of Figures 8 a and b, at transmission time, the circuit is configured to send a series of binary signals. When sending a "1" as shown in Figure 8a, both Ql and Q2 are opened. The ends of the inductor L are "opened", presenting high impedance to the receiver/dock circuitry. Accordingly, there is no absorption of magnetic energy. Therefore the signal on the reception coil is logic "high". It should be noted that the protection diodes 601, 602 are opposing, and no current can flow there through.

[0083] When sending a "1" as shown in figure 8b, both Ql and Q2 are closed. The inductor L is shorted, thereby presenting low impedance to the reader and absorbing energy from the magnetic field. Therefore the signal on the reception coil is logic "low". The protection diodes are shorted, and therefor bypassed.

[0084] The above outlined transmission mechanism is inherently low power due to the minimal power requirement in switching the transistors.

[0085] As mentioned the recordal of accurate time and date information is also essential. In order to have a time reference the event recordal device 301 contains a real time clock calendar(RTCC) or clock unit. The time may be set at the time of manufacture and the clock continuously runs at this point. Alternatively, the user may be asked to set the time when the device is started. The first of these alternatives would cause any power source in the MDI to be depleted during the storage and shelf life and would require additional configuration steps during manufacture. The alternative would require a user interface which would increase the costs associated with the event recordal device and require modification to a standard conventional MDI.

[0086] A second alternative requiring no user intervention is proposed below which removes the need for user interaction at the MDI and also saves power by prohibiting use of the power supply during shelf storage.

[0087] As mentioned above in relation to figure 5, the device is started 501. Starting of the device includes activating a power supply for the device. This may be achieved by connecting the power supply to the event recordal device. For example a seal or other insulation may be arranged between the power supply and the event recordal device. For example, where the power supply is a battery circuit the battery may be insulated from the event recordal device using a seal or other insulation strip. In a preferred configuration the seal is an extension of the sear of the inhaler. At first use, the user of the inhaler removes the seal which in turn closes the circuit and starts the clock unit. This ensures that activations of the inhaler is recorded by the event recordal device.

[0088] The clock starts with a standard date and time as shown in 502, 01/01/2000 00.00.00. All subsequent events are therefore recorded offset to that date. At the time of data retrieval, the date and time of the clock unit are requested by the reader. This information is transferred to the reader which employs a regression algorithm to determine the real time and date of the actual events.

[0089] The steps performed in determining the date and time are outlined in Figures 9 and 10.

[0090] The clock unit of the event recordal device is initialised with a start date and time.

[0091] For example

[0092] the clock starts on 01/02/2013, at 01:00:00 - the reference date and time is 01/01/2000 00:00:00 (TO). This information is stored in the memory of the event recordal device.

[0093] Subsequent actuations are also recorded offset to this initial clock. For example the device is used on 01/02/2013, at 01:01:00 - recorded date and time is 01/01/2000 00:01:00 - Tlr.

[0094] The next usage event is on 02/02/2013, at 02:00:00 - recorded date and time is 02/01/2000 01:00:00 -T2r; [0095] The reader 302 queries the event recordal device 301 to obtain the date and time information. The MCU 307 in the event recordal device retrieves the date and time information stored in the memory 309. This is then transmitted to the reader 302 using the mechanism described above. The reader MCU 314 retrieves 901 the internal time transmitted by the event recordal device. The reader MCU 314 also retrieves 902 the actual time. This may be obtained from the personal computer device or directly from a clock unit on the reader. For example, the data is read on 01/03/2013, at 12:00:00 (actual date/time - Ta) - reported time from the ICC is 01/02/2000 11:00:00 (internal date/time- Ti). From these figures the actual time of actuation of the event recordal device is calculated, 903.

[0096] For ease of explanation in the following example all months are considered to be 30 days long. Calculations are based on the number of days which have passed since activation.

[0097] Determining the date and start time

[0098] date and time of start of the device: Ts = Ta- (Ti - TO);

[0099] Ts = 01/03/2013 12:00:00 - (01/02/2000 11:00:00 - 01/01/2000 00:00:00)

[00100] Ts = 01/03/2013 12:00:00 - (30 days, 11 hours)

[00101 ] Ts = 01/02/2013 01:00:00. This is the start time and date of the device.

[00102] Subsequently, the reader queries the event recordal device to determine if there are additional records to retrieve. If no, then the data retrieval is suspended 908. If yes then the event recordal MCU obtains information from the memory unit. This information is then transmitted back to the reader. The reader MCU then determines 906 the actual date and time of the relevant event. This is the record time, Tn.

[00103] Determining the date and time of the first event, Tn=Tl

[00104] date and time of the first event: TI = Ts + (Tlr-T0);

[00105] TI = 01/02/2013 01:00:00 + (01/01/2000 00:01:00 - 01/01/2000 00:00:00)

[00106] TI = 01/02/2013 01:00:00 + (0 days, 00:01:00)

[00107] TI = 01/02/2013 01:01:00 -date and time of first actuation

[00108] Determining the date and time of the second event, Tn=T2

[00109] date and time of the second event: T2 = Ts + (T2r-T0);

[00110] T2 = 01/02/2013 01:00:00 + (02/01/2000 01:00:00 - 01/01/2000 00:00:00)

[00111 ] T2 = 01/02/2013 01:00:00 + (31 days, 01:00:00)

[00112] T2 = 02/03/2013 02:00:00 -> date and time of second event

[00113] By determining the corrected actual dates and times at the reader the processing overhead required at the event recordal device is minimised. By initialising the clock on startup power requirements are minimised. While it has been described above as being implemented on the reader, it will be appreciated that the outlined algorithm may also be implemented on the personal computing device in communication with the reader. The reader will communicate with the event recordal device, however the calculations will be implemented on the personal computing device with the information obtained.

[00114] An alternative method of calculating the actual time is shown in Figure 10.

While steps 901 and 902 are identical, rather than calculating a start time, the obtained information is used to calculate an offset time Toff.

[00115] Toff=Ta-Ti.

[00116] Subsequently this is used to calculate the record time Tn, where Tn= Toff+Tr.

[00117] Regardless of the method of obtaining the record time this time is stored 907 for subsequent analysis.

[00118] The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[00119] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Claims

1. An event recordal device (104, 301) for an inhaler (100), comprising

a sensor (308), an antenna (310, 403) and a switching circuit (404), wherein the sensor (308) is arranged to (308) sense an actuation event;

the antenna (310, 403) is configured to receive a query from a remote reader (302) and transmit a modulated response indicative of the query and at least one sensed event to the reader in response to the received query; and

the switching circuit (404) is arranged to modulate the response during transmission from the antenna.

2. The event recordal device (104, 301) according to claim 1 wherein the switching circuit (404) is arranged to short a first node (405) and a second node (406) of the antenna to modulate the response.

3. The event recordal device (104, 301) according to claim 2 wherein the switching circuit comprises a switch configured to short the first node (405) and the second node (406) by alternating between an open and a closed state.

4. The event recordal device (104, 301) according to claim 2 or 3 wherein the

switching circuit is arranged to short the first node (405) and second node (406) in a sequence indicative of the sensed event.

5. The event recordal device (104, 301) according to any of claims 1 to 4 wherein the antenna comprises a coil.

6. The event recordal device (104, 301) according to claim 3 wherein the switch comprises a metal oxide semiconductor field effect transistor, MOSFET.

7. The event recordal device (104, 301) according to any previous claim further comprising a clock unit (306) for determining a time stamp corresponding to the sensed event.

8. The event recordal device according to claim 7 wherein the response indicative of the sensed event includes the time stamp for the sensed event.

9. The event recordal device according to claim 7 or 8 wherein the time stamp

includes the time and date of the sensed event.

10. The event recordal device (104, 301) according to any previous claim wherein the modulated response is further based on a determined characteristic of the event.

11. The event recordal device (104, 301) according to claim 8 or 9 wherein the time stamp is offset to an activation time of the event recordal device.

12. The event recordal device (104, 301) according to Claim 11 wherein the response indicative of the sensed event includes the activation time of the event recordal device.

13. The event recordal device (104, 301) according to claim 12 wherein the activation time is zero hours, zero minutes and zero seconds.

14. The event recordal device (104, 301) according to any of claims 12 or 13 wherein activation time further comprises an activation date of the event recordal device.

15. The event recordal device (104, 301) according to any previous claim further comprising a power supply circuit.

16. The event recordal device (104, 301) according to claim 15 further comprising means for activating the power supply circuit.

17. The event recordal device (104, 301) according to Claim 16 wherein the power supply circuit comprises a battery.

18. The event recordal device (104, 301) according to Claim 17 wherein the means activating the power supply circuit comprises a seal arranged to inhibit electrical connection to the battery and wherein activating the power supply circuit comprises removing the seal.

19. The event recordal device (104, 301) according to any previous claim further comprising an actuator (202, 304) for generating the event.

20. The event recordal device (104, 301) according to Claim 19 wherein the actuator (202,304) is selected from the list including a magnetic, a light or a movement actuator.

21. The event recordal device (104, 301) according to any previous claim further comprising a microcontroller unit, MCU (307) in communication with the sensor.

22. The event recordal device (104, 301) of Claim 21 wherein the MCU (307) is

configured to perform integrity checks on the sensed event.

23. The event recordal device (104, 301) of any of Claims 21 or 22 wherein the MCU (307) is configured to filter the sensed event.

24. The event recordal device (104, 301) of any of Claims 21 to 23, when dependent on any of Claims 8 to 11, wherein the MCU (307) is configured to obtain the time stamp from the clock unit.

25. The event recordal device (104, 301) of Claim 24 further comprising a memory (309) in communication with the MCU (307) and configured to store the time stamp.

26. The event recordal device (104, 301) of any of Claims 21 to 25 wherein the MCU (307) is further arranged to initiate modulated transmission from the antenna to the reader in response to an excitation signal induced by the reader in the antenna.

27. The event recordal device (104, 301) according to claim 26 wherein the MCU (307) is configured to periodically determine whether an excitation signal has been induced by the reader (302) in the antenna (310).

28. The event recordal device (104, 301) according to any of claims 21 to 27 wherein the MCU (307) is arranged to cooperate with the switching circuit (404) to short the first and second node.

29. The event recordal device (104, 301) according to any previous claim further

comprising a user interface (203).

30. The event recordal device (104, 301) according to any previous claim wherein an actuation event comprises actuation of the inhaler.

31. An inhaler (100) comprising the event recordal device according to any of Claims 1 to 30.

32. A reader (302) for use with the event recordal device according to any of Claim 1 to 30, comprising:

a receiver (401, 312) for receiving a modulated response from the event recordal device;

an excitation means (402) arranged to induce an alternating excitation signal in the antenna (403) of the event recordal device and the receiver (401, 312), wherein the excitation means (402) is further configured to modulate the alternating excitation signal to communicate a query to the event recordal device.

33. A reader (302) according to Claim 32, wherein the query is encoded using

amplitude shift keying, ASK.

34. A reader according to any of Claims 32 or 33 further comprising a microcontroller unit, MCU (314) for processing the received response from the event recordal device.

35. The reader according to Claim 34 wherein the received response includes a time stamp for an actuation event, the time stamp being offset to an activation time of the event recordal device.

36. The reader according to Claim 34 wherein processing the received response

comprises

querying an external device to determine the correct time of calculating; determining the difference between the correct time and the obtained time stamp corresponding to the time of calculating;

37. The reader according to Claim 36 wherein processing the received response

further comprises querying the event recordal device to obtain an activation time of the event recordal device.

38. The reader according to Claim 36 wherein the external device comprises a

personal computing device.

39. The reader according to Claim 32to 38, wherein the alternating excitation signal is permanent or periodic.

40. The reader according to any of Claims 32 to 39 further comprising means for communicating with at least one of a personal computing device or the worldwide web.

41. A system comprising an event recordal device (301) according to any of claims 1 to 30 and a reader (302) according to any of claims 32 to 40.

42. The system of Claim 41 further comprising a personal computing device (303).

43. A method of operating an event recordal device, comprising

sensing an actuation event;

receiving a query from a remote reader (302); and

transmitting a modulated response indicative of the query and at least one sensed event and to the reader (302).

44. The method of Claim 43 further comprising shorting a first node and a second node of an antenna to modulate the response during transmission.

45. The method of Claim 43 or 44 wherein the first node and second node are shorted in a sequence indicative of the sensed event.

46. The method according to any of Claims 43 to 45 further comprising determining a time stamp corresponding to the sensed event.

47. The method according to Claim 46 further comprising storing the determined time stamp.

48. The method according to any of Claims 43 to 47 wherein the time stamp includes the time and date of the sensed event.

49. The method according to Claims 47 or 48 wherein the time stamp is offset to an activation time of the event recordal device.

50. The method according to any of Claims 43 to 49 wherein the sensed event includes the activation time of the event recordal device.

51. The method according to Claim 50 wherein the activation time further comprises an activation date of the event recordal device.

52. The method according to any of Claims 43 to 51 further comprising performing at least one of integrity checks or filtering.

53. The method according to any of Claims 43 to 52 further comprising initiating

transmission of the modulated response in response to an excitation signal induced by the a reader in an antenna of the event recordal device.

54. The method according to Claim 53 further comprising periodically determining whether an excitation signal has been induced.

55. A method of correcting a time stamp for an actuation event, comprising:

determine the time of the query;

56. The method of Claim 55 further comprising querying the event recordal device to obtain an activation time of the event recordal device.

57. The method of Claim 56 further comprising determining a corrected start time of the event recordal device based on the activation time of the event recordal device, wherein determining the corrected start time comprises determining the difference between the obtained time stamp corresponding to the time of processing and the activation time and subtracting the difference from the time of the query.

58. The method of Claim 57 wherein correcting the time stamp is further based on the corrected start time.

59. An event recordal device as described herein with reference to the appended drawings.

60. A reader as described herein with reference to Figures 3 and 4.

61. An inhaler as described herein with reference to Figure 1.