whilst the invention has been described above it extends to any inventive combination of the features set out above or in the following description . the invention may be performed in various ways , and , by way of example only , an embodiment thereof will now be described by way of example only , reference being made to the accompanying drawings in which : fig1 is a schematic view of an embodiment of a defibrillator in accordance with this invention , and fig2 is a block diagram illustrating the control system of the defibrillator of fig1 . referring initially to fig1 , a semi - automatic automated external defibrillator in accordance with the invention is illustrated . the defibrillator includes a plastic case 10 with a carrying handle 12 on the top portion . the plastic casing 10 contains the storage battery control circuitry and associated equipment for the defibrillator . associated with the handle 12 of the defibrillator is a handle switch 14 which , in this embodiment , is a capacitive switch although it could be a micro - switch . the casing 10 includes a compartment 16 for the storage of electrode pads 18 and appropriate sensors 20 and 22 may be provided to detect opening of the electrode compartment 16 and / or removal of the electrodes . the defibrillator includes a visual display screen 24 and a loudspeaker 26 from which audio or visual instructions may be issued . the casing also includes an ‘ activation ’ button 28 and , internally of the casing , respective attitude sensors 30 and 32 for detecting the attitude of the casing relative to orthogonal axes . also associated with casing is a further touch - sensitive region 34 . in operation , the defibrillator is arranged such that it switches from an off state to an on state as soon as an operator grabs the handle . one example of a control system for the defibrillator of fig1 is shown in fig2 . the rescue mode operation of the defibrillator is initiated when an operator grabs the handle 14 on the top portion in order to carry or move the defibrillator 10 . the switch 14 mounted within the handle casing detects the grabbing of the handle and effectively functions as an on / off switch . in response to this action , a power control circuit 36 activates a power generation circuit 38 and initiates a rescue mode operation of a processor 40 . the processor 40 then begins a rescue mode operation by performing a self - test and then initiates the generation of an audible voice prompt via the loudspeaker 26 “ take to rescue site and remove electrode pads .” such audio prompting may be reinforced or replaced by visual elements e . g . on a display 24 without departing from the scope of the patent . once the processor 40 has performed the self - test and on the condition that the defibrillator is functioning correctly , the processor then repeats the audio prompt , “ take to rescue site and remove pads .” assuming that the handle is still being used to carry the defibrillator , the audio prompting will continue to repeat at a predetermined rate unless removal of the electrodes 18 from the defibrillator casing 10 has been detected by sensor 22 , or removal of the electrodes upon the patient . if desired , at a defined time following the initial grasping of the handle 12 , the audio prompting may become less frequent or cease altogether . this would prevent the battery powering the defibrillator system from being unnecessarily depleted and will also prevent the device becoming a audible nuisance if it were just being transported without any form of carry case or bag . should the device be placed down and then picked up again , thereby reactivating the handle , the process would start from the beginning . upon removing the electrodes 18 from the casing and / or upon removing the electrodes from their associated packaging , the processor 40 guides the operator through a sequence of actions required to enable the aed to achieve a stage capable of performing an ecg analysis and subsequent rescue shock if necessary . this typically involves placing the electrodes 18 upon the patients &# 39 ; chest , checking the airway , breathing and circulation of the patient and monitoring the impedance between the electrodes for future reference if a shock were to be required . in another embodiment , if the processor detects that the defibrillator has been activated and then deactivated , e . g . by the operator grabbing the handle and subsequently placing the unit down and releasing the handle , it may issue verbal instructions to guide the operator to attach a pair of defibrillator electrodes 18 not presently connected . furthermore in another variation , the processor may detect when the electrode pads are connected and when they are not automatically , and issue a suitable announcement such as e . g . “ unit in travel mode ” or “ unit ok ” as appropriate . in a third embodiment the defibrillator may guide the operator to touch a further “ activation ” or “ continue rescue ” button 28 in order for the rescue to proceed . in a fourth embodiment the defibrillator may have further sensors to detect at which stage the rescue is currently at and determine its audible or visual prompts accordingly . such sensors may be attitude sensors 30 , 32 capable of detecting whether the device is vertical or horizontal , and whether the device has been mistakenly placed on the ground the wrong way round . these sensors may only activate when the handle activation button 14 is released , or alternatively may be active for a predetermined time relative to the activation of the handle button 14 . naturally after the completion of a rescue the operator will activate the handle sensor 14 again when attempting to place the defibrillator back in storage or transport the unit with the patient to a nearby hospital facility . this post - rescue activation will cause the processor 40 to collect and to provide post - rescue data . this way includes instructions as to how to download or transfer any rescue data that may be held in memory , or as to the state of the battery and whether a recharge or replace will be necessary , or instruct the operator to replace the electrodes 18 used during the rescue . furthermore , the defibrillator contains an output interface 44 to enable any stored data to be transferred to a remote or local data storage or processing facility either directly by electrical cable , infra - red communication or wireless applications or via connection to a modem and subsequently to a communication network ( for example across an internet or intranet connection ). such data may include collected data during a rescue such as ecg , impedance , respiration , defibrillation data and audio or visual data collected by a microphone or camera as well as data collected during the defibrillator &# 39 ; s lifetime ( self test data , event history etc ). traditionally such data will require a large amount of memory and transfer across a data connection can take anywhere up to an hour if the connection is not high speed or if the data connection has a large amount of data traffic at that time . as can be appreciated requiring such a large amount of time to study any urgent data is not acceptable . to reduce this data transfer time post - rescue , gripping the handle 12 after use signals the defibrillator to compress the data stored in a memory 46 using a compression algorithm 48 prior to the transfer of data . such a compression operation on such a large amount of data can take up to ten minutes or so . hence such an essential operation is performed while the defibrillator is in transit to either a carry bag or being taken with the patient to a hospital and the unit is confirmed to not be in a rescue state ( i . e the unit has been picked up ). should the handle switch 14 again be activated and new electrodes used to perform a second rescue , the compression can be halted and data relating to a new rescue stored in the available memory . following the release of the post - rescue handle activation the defibrillator 10 may perform an additional self test to ensure that no damage occurred during transit . in , summary therefore the described embodiment and the various possible modifications illustrate an example of an automated or semi - automated defibrillator that automatically changes the operation mode , prior to any intended use , when an operator contacts a section or sections of the casing . in one embodiment operation mode of the defibrillator changes from a sleep mode to an on mode ; in another , the operation mode of the defibrillator may change from an off mode to an on mode . furthermore , the defibrillator can be designed to automatically change the operational mode when the operator has no contact with a section or sections of the casing for a predetermined amount of time . thus the operational mode of the defibrillator may change from an on mode to a sleep mode or alternatively from an on mode to an off mode . this automatic activation has been found to often decrease the time it takes the operator — particularly an inexperienced or anxious operator — to set up and use the aed to resuscitate a patient in cardiac arrest . furthermore , the operational mode of the defibrillator can be configured to change to a self - test mode when an operator contacts a section or sections of the casing prior to or following any intended use of the defibrillator . thus the tested functions could include the presence and interconnection of defibrillator electrodes , battery charge state and the operability of the high voltage circuit . visual and audible indicators are used to alert an operator if faults are identified . a record of each self - test may be stored in memory , and can be subsequently retrieved through a communications port or transmitted to a communications device via a transmitter module .
a defibrillator device is provided with a switch or proximity sensor adjacent a remote region on its casing or housing . the defibrillator changes its operational state when touched or handled , or when proximity is detected , so activating the device without requiring an operator to determine the location of an on / off switch .