Electronic Cigarette and Method for Controlling an Electronic Cigarette

Abstract

An electronic cigarette includes a vaporizing unit configured to generate a vapor from a substrate; an air flow inlet; a vapor outlet configured for a user to inhale the vapor; a main vapor flow channel extending past the vaporizing unit from the air flow inlet to the vapor outlet; a pressure sensor arranged to measure a pressure at the main vapor flow channel; and control circuitry configured to monitor user inhalation by: obtaining pressure measurements from the pressure sensor at a sampling frequency; calculating a background pressure as a moving average of the pressure measurements obtained within a moving sampling period; and calculating a current pressure difference as a difference between a current pressure measurement and the background pressure. The control circuitry is configured to select an operation state depending upon the current pressure difference. The operation state is one of: at least a sleep state; and an active state.

1 . An electronic cigarette comprising:
 a vaporizing unit configured to generate a vapor from a substrate;   an air flow inlet;   a vapor outlet configured for a user to inhale the vapor;   a main vapor flow channel extending past the vaporizing unit from the air flow inlet to the vapor outlet;   a pressure sensor arranged to measure a pressure at the main vapor flow channel; and   control circuitry configured to monitor user inhalation by:
 obtaining pressure measurements from the pressure sensor at a sampling frequency; 
 calculating a background pressure as a moving average of the pressure measurements obtained within a moving sampling period; and 
 calculating a current pressure difference as a difference between a current pressure measurement and the background pressure, 
   wherein the control circuitry is configured to select an operation state in dependence upon the current pressure difference, wherein the operation state is one of a plurality of states comprising:   a sleep state in which the sampling frequency is a first frequency; and an active state in which the sampling frequency is a second frequency higher than the first frequency,   the electronic cigarette further comprising an accelerometer configured to measure an acceleration of the electronic cigarette, wherein the control circuitry is configured to switch from the sleep state to the active state in response to the acceleration exceeding a threshold, and wherein the control circuitry is further configured to respond to an acceleration sustained in a specific direction for at least a threshold period of time by switching the sampling frequency to a high sampling frequency higher than the second frequency.   
     
     
         2 . An electronic cigarette according to  claim 1 , wherein the control circuitry is configured to switch from the sleep state to the active state in response to the current pressure difference exceeding a first threshold. 
     
     
         3 . An electronic cigarette according to  claim 1 , wherein the plurality of states further comprises a vaping state in which the control circuitry controls the vaporizing unit to generate the vapor. 
     
     
         4 . An electronic cigarette according to  claim 3  wherein, in the vaping state, the sampling frequency is a third frequency higher than the second frequency. 
     
     
         5 . An electronic cigarette according to  claim 1 , wherein the control circuitry is configured to switch to the vaping state in response to the current pressure difference exceeding a second threshold, the second threshold indicating that a user is inhaling at the vapor outlet. 
     
     
         6 . An electronic cigarette according to  claim 1 , wherein the pressure sensor is configured to measure an absolute pressure. 
     
     
         7 . An electronic cigarette according to  claim 6 , wherein the pressure sensor is a MEMS sensor. 
     
     
         8 . An electronic cigarette according to  claim 6 , wherein the control circuitry is configured to estimate a temperature based on the background pressure. 
     
     
         9 . A control circuit for controlling an electronic cigarette, the electronic cigarette comprising: a vaporizing unit configured to generate a vapor from a substrate; an air flow inlet; an vapor outlet; a main vapor flow channel extending past the vaporizing unit from the air flow inlet to the vapor outlet; a pressure sensor arranged to measure a pressure at the main vapor flow channel, or arranged near to the air flow inlet or the vapor outlet; and an accelerometer configured to measure an acceleration of the electronic cigarette,
 wherein the control circuit is configured to monitor user inhalation by:
 obtaining pressure measurements from the pressure sensor at a sampling frequency; 
 calculating a background pressure as a moving average of the pressure measurements obtained within a moving sampling period; and 
 calculating a current pressure difference as a difference between a current pressure measurement and the background pressure, 
   wherein the control circuit is configured to select an operation state in dependence upon the current pressure difference, wherein the operation state is one of a plurality of states comprising: a sleep state in which the sampling frequency is a first frequency; and an active state in which the sampling frequency is a second frequency higher than the first frequency, and   wherein the control circuitry is configured to switch from the sleep state to the active state in response to the acceleration exceeding a threshold, and wherein the control circuitry is further configured to respond to an acceleration sustained in a specific direction for at least a threshold period of time by switching the sampling frequency to a high sampling frequency higher than the second frequency.   
     
     
         10 . A method for controlling an electronic cigarette comprising: a vaporizing unit configured to generate a vapor from a substrate; an air flow inlet; an vapor outlet; a main vapor flow channel extending past the vaporizing unit from the air flow inlet to the vapor outlet; a pressure sensor arranged to measure a pressure at the main vapor flow channel, or arranged near to the air flow inlet or the vapor outlet; and an accelerometer configured to measure an acceleration of the electronic cigarette, the method comprising monitoring user inhalation by:
 obtaining pressure measurements from the pressure sensor at a sampling frequency;   calculating a background pressure as a moving average of the pressure measurements obtained within a moving sampling period;   calculating a current pressure difference as a difference between a current pressure measurement and the background pressure; and   selecting an operation state in dependence upon the current pressure difference, wherein the operation state is one of a plurality of states comprising: a sleep state in which the sampling frequency is a first frequency; and an active state in which the sampling frequency is a second frequency higher than the first frequency,   wherein the control circuitry is configured to switch from the sleep state to the active state in response to the acceleration exceeding a threshold, and wherein the control circuitry is further configured to respond to an acceleration sustained in a specific direction for at least a threshold period of time by switching the sampling frequency to a high sampling frequency higher than the second frequency.   
     
     
         11 . A non-transitory computer-readable medium storing instructions which, when executed by a processor, cause the processor to perform a method according to  claim 10 . 
     
     
         12 . (canceled) 
     
     
         13 . An electronic cigarette according to  claim 7 , wherein the control circuitry is configured to estimate a temperature based on the background pressure.