Abstract:
A method for operating an event counter, including the following: ascertaining at least one counting event with the aid of a signal from a first sensor; and using a signal from a second sensor for ascertaining the counting event if the signal from the first sensor is unable to be unequivocally allocated to a counting event.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a method for operating an event counter. Furthermore, the present invention relates to a device for counting events. 
       BACKGROUND INFORMATION 
       [0002]    Event counters that are used for extracting step events from an acceleration signal are known from the related art. Such a step counter is discussed in the document EP 1 770 368 A1, for example. The extraction of the step events is based on a detection of a peak or a peak value of a signal. In most cases, the known systems use a sensor modality, e.g., in the form of an acceleration signal. This may result in a partially faulty detection of events if the event counter is subjected to driving motions that feature intense changes in direction (e.g., serpentine driving maneuvers) or if it is exposed to vibrations. 
       DISCLOSURE OF THE INVENTION 
       [0003]    Therefore, it is an object of the present invention to provide an improved method for operating an event counter. 
         [0004]    According to a first aspect, the object is achieved by a method for operating an event counter, the method having the following steps:
       Ascertaining at least one counting event with the aid of a signal from a first sensor; and   Using a signal from a second sensor for ascertaining the counting event if the signal from the first sensor is unable to be unequivocally allocated to a counting event.       
 
         [0007]    This advantageously makes it possible to detect or count only events that are actually also meant to be detected or counted. 
         [0008]    The second sensor is therefore connected only temporarily, so that it is ascertained in a highly reliable manner whether or not a counting event is at hand. 
         [0009]    Specific embodiments of the method are the subject matter of the further descriptions herein. 
         [0010]    In one advantageous further refinement of the method, the signal from the second sensor is used periodically across a service life of the event counter. This advantageously makes it possible to achieve a very high detection accuracy. 
         [0011]    In another advantageous further refinement of the method, the signal from the second sensor is connected if a defined property of the signal from the first sensor is present. This makes it possible to perform a type of plausibilization that realizes an adaptive connection, in which the counting event is verified. A connection thus takes place only when it is assumed that a counting event has most likely taken place. 
         [0012]    In one advantageous further refinement of the method, the defined property of the signal from the first sensor is one of: arithmetic mean value, standard deviation, a ratio of high to low value within a time period. In this way appropriate signal values are used for carrying out a plausibilization of the counting event. 
         [0013]    In another advantageous further refinement of the method, a minimum time interval is observed between the connections of the signal from the second sensor. This advantageously eliminates scenarios in which situations are at hand that do not represent genuine counting events. 
         [0014]    In another advantageous further refinement of the method, the signal from the second sensor is periodically connected only if the signal from the first sensor has a defined property. This enables a maximum detection quality and energy savings because the second sensor is periodically connected only if it is highly likely that a counting event is present. 
         [0015]    According to another advantageous further refinement of the method, related different operating modes of the event counter are thereby able to be adjusted. This may be undertaken by a user of the event counter, for instance. 
         [0016]    In another advantageous further refinement of the method, the first sensor is an acceleration sensor and the second sensor is a rate-of-rotation sensor. Signals from sensors are thereby used that lend themselves very well to the differentiation of counting events. 
         [0017]    According to another advantageous further refinement of the method, the event counter is a step counter. The plausibilization of step events can be used to particular advantage in this type of event counter because the step counter is often used in ambiguous situations that do not represent counting events. 
         [0018]    In the following text, the present invention will be described with further features and advantages on the basis of a plurality of figures. All of the features, regardless of their presentation in the description or in the figures, and regardless of their antecedent references in the patent claims, form the subject matter of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows a first specific embodiment of a sequence of a method according to the present invention. 
           [0020]      FIG. 2  shows a further variant of a sequence of the method of the present invention. 
           [0021]      FIG. 3  shows a further variant of a sequence of the method of the present invention. 
           [0022]      FIG. 4  shows a specific embodiment of an event counter according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In methods from the related art, an absolute amount of an acceleration is calculated from a signal of an acceleration sensor. Peak values are subsequently detected, and a minimum time interval between the peak values is observed for checking a plausibility. However, this known method may disadvantageously lead to a high number of incorrect or faulty detections, for instance because of jolting during the vehicle operation to which the event counter is exposed. 
         [0024]    For suppression, and thus for increasing the detection accuracy, the use of a rate-of-rotation sensor is proposed, which is connected only temporarily and, in particular, is connected only when a likelihood of a counting event exists. 
         [0025]    In this manner, a scenario of “driving an automobile” can be identified from a combination of the sensor signals of the acceleration sensor and the rate-of-rotation sensor. To do so, properties of the sensor signal from the acceleration sensor are ascertained or extracted. For example, these properties could be a mathematical mean value, a standard deviation, a relation of high to low values within a time segment, etc. 
         [0026]    In order to minimize an electrical energy consumption of the overall system, the rate-of-rotation sensor as electrical main consumer is connected as rarely as possible. This may be done in various manners, which are described in the following text. 
         [0027]      FIG. 1  essentially shows that the rate-of-rotation sensor is periodically switched on in a fixed time-slot pattern and the criterion for the counting of steps is checked (“periodic variant”). 
         [0028]    In a step  200 , a value of an acceleration is ascertained. In a step  201 , a counting event such as a step is detected, which is buffer-stored in a step  202 . In a step  202 , a signal from a rate-of-rotation sensor is periodically connected. In a step  203 , it is then decided whether the event count is valid (step  204 ) or will be discarded (step  205 ). For example, it is possible to implement the periodic connection of the signal from the rate-of-rotation sensor, executed in step  202 , once per second or once per minute, distributed across an entire service life of the event counter. Of course, any connection time periods that are deemed advantageous are conceivable. 
         [0029]    The described method thus connects the signal from the rate-of-rotation sensor on a regular basis, which may actually cause a certain increase in the electrical consumption for the event counter, but allows the realization of a very precise operating behavior of the event counter. 
         [0030]    A variation of the method is shown in principle in the flow diagram of  FIG. 2 , the rate-of-rotation sensor being used adaptively as a function of a signal from the acceleration sensor in this case (“adaptive variant”). This advantageously makes it possible to reduce the energy consumption for the rate-of-rotation sensor when the criterion for switching on the rate-of-rotation sensor is not met most of the time. Steps  300  through  302  correspond to steps  200  to  202  in  FIG. 1 . In a step  303 , a criterion is used that corresponds to a counting event that appears probable. In a step  304 , a decision is then made whether the event count is valid (step  305 ) or will be discarded (step  306 ). 
         [0031]    Another variant of the method is shown in principle in  FIG. 3 . Steps  400  through  402  correspond to steps  200  through  202  of  FIG. 1  or to steps  300  through  302  of  FIG. 2 . In a step  403 , the criterion of the signal from the rate-of-rotation sensor is applied periodically, and in a step  404 , a decision is made whether the counting event is valid (step  405 ) or will be discarded (step  406 ). 
         [0032]    It is therefore clear from  FIG. 3  that the method constitutes an adaptive-periodic variant, in which the signal from the rate-of-rotation sensor is periodically connected at times when a connection criterion is satisfied, in order to further reduce the energy consumption. In this manner, a minimal electrical energy consumption is able to be achieved by this variant. 
         [0033]    In an advantageous manner, a selection of the three different operating modes of the event counter described in  FIGS. 1  through  3  can be set either by a user, for instance via a selection with regard to a related electrical energy consumption. Another option is a fixed allocation of the operating mode to a design of the event counter, for instance in the form of a tablet, a smartphone, a sport wristband, a fitness tracker, etc. 
         [0034]      FIG. 4  schematically illustrates an event counter  100  in a highly simplified manner. It can be seen that event counter  100  includes a first sensor  10  in the form of an acceleration sensor and a second sensor  20  in the form of a rate-of-rotation sensor. Signals from said sensors  10 ,  20  are exchanged among the sensors, and/or supplied to a computer device  30  (e.g., a microcontroller or an ASIC), the signal from the rate-of-rotation sensor being connected only temporarily for an ascertainment of counting events, and as a function of certain criteria. 
         [0035]    The method of the present invention may advantageously be implemented as an algorithm of a software program for computer device  30 ; certain restrictions with regard to the specific development of the algorithm may possibly exist as a function of form factors. 
         [0036]    In summary, the present invention provides an improved method for operating an event counter, by which it is advantageously possible to increase a detection accuracy of counting events, while a related additional electrical energy consumption is minimized. 
         [0037]    For this purpose, the step counter is supplemented by various plausibility queries. If the information received from the acceleration sensor is insufficient to carry out a complete plausibility check, then at least one additional sensor, such as the rate-of-rotation sensor, is connected as well. Of course, it is also possible to use signals from a plurality of sensors for the plausibility checks. 
         [0038]    The detection accuracy can advantageously be optimized in this manner, while keeping the additional electrical energy consumption as low as possible. Overall, the method of the present invention makes it possible to suppress, or at least minimize, a “false positive detection” of step events, in which steps are counted or detected only if they are also actually occurring. In the event that no steps are at hand, they will also not be counted or detected. This contributes to an optimal parameterization of the step counter. 
         [0039]    Although the present invention has been described in the preceding text with the aid of specific exemplary embodiments, it is by no means restricted to these embodiments. One skilled in the art will therefore be able to modify the afore-described features in a suitable manner or combine them with one another without departing from the core of the present invention.