Electrochemical sensor device, breath alcohol measuring apparatus and method for determining electrode activity of an electrochemical sensor

Abstract

The invention relates to an electrochemical sensor device (10) for a breath alcohol measuring device (100), a corresponding breath alcohol measuring device (100) and a method for determining the activity of an electrode of an electrochemical sensor. The electrochemical sensor device comprises an electrochemical sensor with at least two electrodes (12, 14). The electrochemical sensor device further comprises a heat source (16). The heat source is arranged such that, when activated, the heat source selectively heats one of the electrodes (12) of the electrochemical sensor.

Description

Technical Field

[0001] The invention relates to an electrochemical sensor arrangement for a breath alcohol measuring device, a corresponding breath alcohol measuring device and a method for determining the activity of an electrode of an electrochemical sensor, for example for measuring the activity of an electrochemical sensor. Background Art

[0002] Breath alcohol measuring devices measure the alcohol concentration in a person's breath. Electrochemical sensors based on the principle of a fuel cell are used in mobile measuring devices, but also in some cases for forensic applications. Due to changes in environmental conditions, in particular due to aging and changes in humidity or concentration of aqueous electrolytes, the sensitivity of electrochemical sensors changes. Drying generally slows down some chemical processes of the sensor and the sensor becomes slower. Rewetting can speed up the sensor again. The drying and rewetting processes are not completely reversible here, so that the sensor degrades over time. The sensor temperature also has an influence on the sensor dynamics. In some alcohol sensors, for example, the sensor speed doubles when the sensor temperature increases by about 12°C. The electrode activity is dependent on the degradation of the electrochemical sensor due to drying.

[0003] The identification of a slow, degraded sensor is usually carried out during calibration, for example by evaluating the sensor speed by filling with a target gas. In this case, for example, the evaluation speed is determined and, if necessary, temperature-compensated.

[0004] The disadvantage of the above method is that the vitality detection can only be performed at the time of adjustment. In the meantime, that is, in the field operation, a slow sensor cannot be detected. However, from the customer's point of view, it is desirable to have an early warning of a weak sensor. Summary of the invention

[0005] There is a need for an improved approach to determining the viability of an electrochemical sensor that is capable of determining the viability in the field.

[0006] This need is taken into account by the electrochemical sensor device and the method according to the independent claims.

[0007] The invention is based on the knowledge that the electrode vitality of an electrochemical sensor can be determined by selectively heating one of the electrodes of the electrochemical sensor, thereby forming a voltage between the electrodes and being able to analyze the current flux formed due to the voltage reduction in order to determine the electrode vitality of the electrochemical sensor. This selective heating of one of the electrodes is performed by a heat source, which is arranged as part of the electrochemical sensor device. Therefore, the corresponding voltage can also be generated on site independently of the calibration device. This property can be used to perform the corresponding vitality determination itself at short intervals. Therefore, the determination of vitality can be triggered regularly or manually by the customer. As a result, in at least some embodiments, reliable vitality recognition can be performed on site without gas testing. As a result, the customer can be warned early to replace the sensor (in the sense of predictive maintenance). In addition, based on the vitality, compensation parameters can be adjusted during operation. As a result, the accuracy of the device can be improved. By adjusting the parameters, the calibration interval can be extended, or in some devices, recalibration can even be completely omitted.

[0008] An embodiment of the present invention proposes an electrochemical sensor device for a breath alcohol measuring device. Here, the electrochemical sensor device is not limited to breath alcohol measurement. On the contrary, the electrochemical sensor device can also be used in other contexts. For example, the electrochemical sensor device can be an electrochemical sensor device for a gas measuring device. The electrochemical sensor device includes an electrochemical sensor with at least two electrodes. The electrochemical sensor device further includes a heat source. The heat source is arranged so that when activated, the heat source selectively heats one of the electrodes of the electrochemical sensor. By selectively heating one electrode, a voltage is generated between the two electrodes. If the electrodes are connected via a measuring resistor, a current flows, which is then analyzed to determine the vitality of the corresponding electrochemical sensor, for example, in field operation.

[0009] In at least some embodiments, the heat source is a light source, such as a light emitting diode (LED). This allows contactless heating of one electrode, whereby the invention can also be used with existing electrochemical sensors without requiring structural changes to the actual sensor. Another advantage of LEDs is that they have a high efficiency and mainly emit light. The light penetrates the plastic housing of the sensor only with low attenuation and is absorbed only at the dark electrodes. Thus, one of the electrodes is selectively heated. This heating also takes place contactlessly. As a result, the energy input can be switched off and on again very quickly, and the sensor reacts with a very steep current measurement curve.

[0010] For example, by selectively heating one electrode, a voltage can be generated between the electrodes. The voltage can in turn result in a current flux that can be analyzed in order to determine the viability of the electrochemical sensor.

[0011] In various embodiments, the electrochemical sensor device further comprises a control device. The control device is configured to determine the activity of an electrode based on the selective heating of the electrode, for example based on the voltage generated and the current flux generated thereby. For example, the control device can be configured to perform the method described below. This enables the electrochemical sensor device or a breath alcohol measuring device having an electrochemical sensor device to determine the activity of the electrode in situ.

[0012] In some embodiments, the electrochemical sensor device further comprises a graphic output unit for outputting information about the vitality of the sensor. Here, the information about the vitality of the electrode is determined based on selectively heating one electrode. For example, the control device can be configured to output information about the vitality of the sensor via the graphic output unit. This can provide information about the vitality to a user of the electrochemical sensor device, such as a breath alcohol measuring device. Based on this information, it can be realized for the user to determine when to adjust or update the sensor, or whether the electrochemical sensor is still accurate enough.

[0013] Furthermore, an embodiment of the present invention provides a breath alcohol measurement device comprising an electrochemical sensor arrangement. Thus, the breath alcohol measurement device is capable of testing the vitality of the integrated electrochemical sensor.

[0014] In addition, an embodiment of the present invention proposes a method for determining the activity of an electrode of an electrochemical sensor. The method includes: activating a heat source within a predetermined time period to selectively heat one of the electrodes of the sensor. In addition, the method includes: determining the current flux between the electrodes of the electrochemical sensor. The current flux is based on the voltage caused by the heat source selectively heating one electrode. Therefore, there is a current measurement resistance between these electrodes. In addition, the method includes: determining the activity of the sensor based on the signal shape of the current. Such a method can be performed by a component that can be integrated in a device including an electrochemical sensor, thereby enabling the electrochemical sensor to be tested on site.

[0015] In some embodiments, the method further comprises providing information about the vitality of the sensor via a graphical output unit. Based on this information, it is possible for the user of the electrochemical sensor to determine when to calibrate or update the sensor, or whether the electrochemical sensor is still sufficiently accurate.

[0016] For example, the information about the vitality of the sensor can include information about the estimated remaining duration of the availability of the electrochemical sensor taking into account a preset minimum measurement accuracy. This allows the user to estimate how long he can still operate the corresponding sensor in the device.

[0017] In various embodiments, the method is performed by a device comprising an electrochemical sensor and a heat source. Here, the method can be configured as part of a self-test of the device. This enables regular testing of the electrochemical sensor without the need for a separate testing device.

[0018] In some embodiments, the method further comprises determining a compensation parameter based on the activity of the sensor. The compensation parameter describes the extent to which the activity of the sensor affects the measurement of the sensor. In addition, the method may comprise performing a measurement with the electrochemical sensor taking into account the compensation parameter. For example, for a given sensor activity, the extent to which the measured value deviates from the actual value may be known. This knowledge may be used to determine the compensation parameter based on the determined activity of the electrochemical sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Some examples of the device and / or method are explained in more detail below with reference to the accompanying drawings. In the drawings:

[0020] Figure 1 A schematic diagram showing an embodiment of an electrochemical sensor device and a breath alcohol measurement apparatus having such an electrochemical sensor device;

[0021] Figure 2a A flow chart illustrating one embodiment of a method for determining electrode viability of an electrochemical sensor;

[0022] Figure 2b A schematic block diagram of an embodiment of a control device for determining electrode activity of an electrochemical sensor is shown;

[0023] Figure 3a shows measurements of an electrochemical sensor in an exemplary test setup;

[0024] Figure 3b shows measurements of healthy and dry electrochemical sensors in another exemplary test setup;

[0025] Figure 3c shows ethanol curves for a live and dry electrochemical sensor in another exemplary test setup; and

[0026] Figure 4 The results of measurements from an experimental setup are shown, in which the electrodes of an electrochemical sensor were heated alternately by an LED and a soldering iron in a contactless manner. DETAILED DESCRIPTION

[0027] Various examples are now described in more detail with reference to the accompanying drawings. In the accompanying drawings, the thickness of lines, layers and / or regions may be exaggerated for clarity.

[0028] Other examples may encompass modifications, equivalents, and alternatives that fall within the scope of the present disclosure. Throughout the description of the drawings, the same or similar reference numerals represent the same or similar elements, which may be implemented identically or in a modified form when compared to each other, and which provide the same or similar functions.

[0029] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, these elements may be directly connected or coupled, or connected or coupled via one or more intermediate elements. When two elements A and B are combined using "or", it should be understood that all possible combinations are disclosed; that is, only A, only B, and A and B, unless otherwise explicitly or implicitly defined. Alternative expressions for the same combination are "at least one of A and B" or "A and / or B". The same applies, mutatis mutandis, to combinations of more than two elements.

[0030] The present disclosure relates to an electrochemical sensor device, for example for use in a breath alcohol measuring device, and a method for determining the sensor viability of an electrochemical sensor, in particular an alcohol sensor, in situ via thermal excitation, for example by means of light (e.g. from an LED). The test can be performed at any time and does not require the use of a test gas.

[0031] The electrochemical sensor works as a fuel cell. Under the action of ethanol, for example, it electrochemically burns with oxygen in the air and releases electrical energy. In an exemplary implementation, the current is measured with the aid of a 4.3 ohm shunt resistor and a precise 24-bit Delta-Sigma converter. Currents in the nanoampere range are measured here, which means that low-noise measuring electronics are required.

[0032] If an electrochemical sensor is in thermal equilibrium, no voltage is applied to its electrodes and therefore no current flows. The measured value is 0. However, if one electrode of the sensor is heated more than the other, that is, if a temperature gradient exists in the sensor, a thermoelectric voltage is generated, which manifests itself in the form of a current flux. The zero point of the sensor in the device is thereby shifted. This process is generally undesirable, so that for precise measurements, the sensor must be in thermal equilibrium so that its zero point does not drift.

[0033] If two identical electrodes in an electrolyte are irradiated with UV light to different degrees, a voltage can be measured between the two electrodes. This effect was discovered by Alexandre Edmond Becquerel in 1839 and is described in his honor as the Becquerel effect. However, electrochemical sensors, and especially alcohol sensors, are nothing more than such batteries. If an electrochemical sensor is irradiated with UV light, a voltage is generated across the electrodes. The reason for this is that, by irradiation, electrons are raised to higher energy levels due to the absorption of photons. These lead to an increased potential in the electrochemical sensor.

[0034] Both effects, i.e. the current flux due to thermovoltage and due to photovoltage, can be used in the present invention. On the one hand, the thermovoltage is generated by briefly heating the sensor on one side, and on the other hand, the photovoltage is generated by irradiation with UV light. Both short-term voltage generation leads to current curves, which can be evaluated accordingly.

[0035] If the sensor loses balance thermally or optoelectronically, a fast sensor can quickly compensate for the disturbance. A slow sensor needs more time to do this. In addition, the dynamics of a poor sensor appear different.

[0036] Figure 1 Schematic diagram of an embodiment of an electrochemical sensor device 10 and a breath alcohol measuring device 100 having such an electrochemical sensor device 10 is shown. As mentioned above, the same principle can also be applied to the electrochemical sensor device of the gas sensor. Accordingly, Figure 1 Also shown is a gas sensor 100 having such an electrochemical sensor device 10. The electrochemical sensor device comprises an electrochemical sensor 1 with at least two electrodes 12, 14. Figure 1 As shown in FIG, the electrochemical sensor also includes an electrolyte. Figure 1In the embodiment of the present invention, the electrochemical sensor is held in a membrane 13 arranged between a first electrode 12 and a second electrode 14. Here, the electrochemical sensor can be, for example, an electrochemical fuel cell suitable for measuring ethanol in human breath. Alternatively, the electrochemical sensor can be an electrochemical sensor for detecting gas. To this end, the electrochemical sensor device can also include a third electrode, such as a reference electrode. In addition, the electrochemical sensor device 10 includes a heat source 16. The heat source is arranged so that when activated, the heat source selectively heats exactly one of the electrodes of the electrochemical sensor. Optionally, the electrochemical sensor device also includes a control device 20, and an output device 18. Here, the control device can be configured to perform measurements with the aid of an electrochemical sensor. To this end, the electrochemical sensor device can also optionally include a measuring resistor 15 arranged between the terminals of the two electrodes. The output device can be controlled by the control device to output measurement results and other information. In addition, the control device can be configured to control the heat source. Therefore, the control device can be coupled to the electrodes, the heat source and the optional output device, for example.

[0037] The electrochemical sensor comprises two electrodes 12, 14. These electrodes are referred to in the electrochemical sensor as measuring electrode and counter electrode, for example. Based on the current flux between the two electrodes, the measurement is usually performed with the aid of the electrochemical sensor. In this case, during the measuring operation of the electrochemical sensor, an electric potential is generated between the electrodes. When used in a breath alcohol measuring device, the integral of the current curve of the current measured between the electrodes obtained thereby is proportional to the breath alcohol (ethanol in the breath gas) and can be used in a subsequent processing step to determine the breath alcohol. Here, the integral of the current flux corresponds to the charge, which is a measure of the alcohol concentration. For example, a measuring resistor 15 can be used for the measurement.

[0038] In addition, the electrochemical sensor device includes a heat source 16, which is arranged so that it selectively heats one of the electrodes of the electrochemical sensor when activated. In other words, the heat source is configured to selectively heat one of the two electrodes. Here, "selectively" means that the heat source is arranged so that the heat source heats one of the two electrodes more than the other electrode, for example, so that the heat energy absorbed by one electrode is at least twice the heat absorbed by the other electrode, and / or so that due to heating, the temperature increase at one electrode is, for example, in degrees Celsius, at least twice the temperature increase at the other electrode. Ideally, when the heat source is activated, only one electrode is heated, but this is only the case in a few implementations due to the thermal radiation of the one electrode. It is only important here that one of the two electrodes is heated more than the other electrode, so that an electric potential is generated between the electrodes. By selectively heating the one electrode, a voltage is generated between the electrodes. Different types of heat sources and different heat transfer implementations are considered here.

[0039] For example, the heat source can be a light source, such as an LED, or a halogen-based light source or an incandescent lamp. Such LEDs have different advantages for current applications. First, it is achieved that one electrode is heated within a predetermined time period without having to consider heat propagation via a heat conductor, because the light passes through the housing and is mainly absorbed directly on the electrode. In order to be able to evaluate fast dynamics, thermal interference (excitation) should only exist for a short time. Thermal heating based on the principle of heat conduction may not be very suitable, but it will also lead to the desired success. Bright LEDs, especially blue LEDs, have proven to be particularly suitable as radiation sources. These can provide up to 6W of power and more than 70% radiation efficiency during this period. Experiments have also shown that the energy of UV-LEDs is sufficient to generate voltage, especially photoelectric voltage. The advantage of LED excitation is that thermal energy can be directed to the sensor in a targeted and very short time. The power can actually be turned on and off again without delay. In addition, a light source such as an LED can be completely located outside the electrochemical sensor, so that the scheme can also be applied to conventional electrochemical sensors.

[0040] For example, heat transfer or photoelectric influence on electrodes can be implemented wirelessly. Here, wireless is understood as the affected electrode is not wired to a heat source or light source. In other words, the transfer of heat and / or light energy is carried out contactlessly, or generally speaking, the energy transfer is carried out wirelessly and contactlessly. For example, LEDs, thermal radiators, light bulbs or induction can be used here. A light source, such as an LED, can be arranged here so that the light emitted when the light source is activated is absorbed by one electrode but not by the other electrode. In other words, the light source can be oriented so that the light emitted when the light source is activated is directed to the one electrode. The other electrode can be shielded by the light emitted by the light source, for example, by the one electrode. For this purpose, the one electrode 12 can be arranged, for example, between the light source 16 and the other electrode 14.

[0041] Alternatively to the light source, other types of heat sources, such as resistive heaters, can also be used. In these cases, heat can be transferred to one electrode by means of a heat conductor. In other words, a heat source can be used in combination with a heat conductor to heat exactly one of the electrodes.

[0042] In some embodiments, as described above, the electrochemical sensor device includes a control device 20. The control device can generally be configured to perform measurements with the aid of the electrochemical sensor. The control device can also be configured to determine the activity of the electrode based on the selective heating of the one electrode. To this end, the control device can be configured to activate a heat source on the one hand to generate a voltage between the electrodes. On the other hand, the control device can be configured to measure the current flow based on the generated voltage and determine the activity of the electrochemical sensor based on this. Therefore, the control device can be configured to determine the activity of the electrode without using a test gas. To this end, the control device can be configured, for example, to perform Figure 2aTherefore, more details on determining vitality will be combined with Figure 2a The method is introduced.

[0043] In general, as mentioned above, the control device 20 can also be used to perform measurements with the aid of an electrochemical sensor. To this end, the control device 20 can be configured to set the potential between the electrodes of the sensor during the measurement operation. In an electrochemical fuel cell, the potential of the measuring electrode is relative to the reference electrode, that is, the potential is the potential difference between the potential of the reference electrode and the potential of the measuring electrode. Therefore, one of the electrodes of the electrochemical sensor can be a measuring electrode, and the other electrode can be a reference electrode. The potential on the measuring electrode can be set, for example, via a so-called constant potential regulating circuit, that is, a circuit that generates a current between the measuring electrode and the counter electrode to set the potential. For example, the control device may include a constant potential regulating circuit or another regulating circuit, which is suitable for setting the potential. Alternatively, the electrochemical sensor can be used as a pure fuel cell, and the current flux is determined in the fuel cell. In addition, the control device can be configured to perform the measurement of the current between the measuring electrode and the counter electrode during the measurement operation.

[0044] In at least some embodiments, the electrochemical sensor device or a device comprising an electrochemical sensor device, such as a breath alcohol measuring device, comprises a graphics output unit. A variety of types of graphics output units are conceivable here. For example, the graphics output unit can be a screen, such as a liquid crystal display or a screen based on organic light-emitting diode (OLED) technology. Alternatively, the graphics output unit can be based on a seven-segment display or one or more status LEDs. The graphics output unit can be used to output information about the vitality of the sensor. For example, the control device can be designed to output information about the vitality of the sensor via the graphics output unit. In this case, the information about the vitality of the electrode is determined based on selectively heating the one electrode. Further details about this are provided in conjunction with Figure 2a The method is introduced.

[0045] In an embodiment, the control device 20 may correspond to any controller or processor or programmable hardware component. For example, the control device 20 may also be implemented as software programmed for the corresponding hardware component. In this regard, the control device 20 may be implemented as programmable hardware with correspondingly adjusted software. Any processor, such as a digital signal processor (DSP), may be used here. The embodiment is not limited to a specific type of processor here. Any processor or multiple processors may be considered for implementing the control device 20.

[0046] Further details and aspects of the electrochemical sensor device or breath alcohol measurement apparatus are described in conjunction with the schemes or examples described before or after, such as Figure 2. The electrochemical sensor device or breath alcohol measurement apparatus may include one or more additional optional features corresponding to one or more aspects of the proposed scheme or described examples as described before or after.

[0047] Figure 2a A method for determining an electrochemical sensor, such as Figure 1 Flow chart of one embodiment of a method 200 for activating an electrode of an electrochemical sensor. The method includes: activating 210 a heat source, such as Figure 1 A heat source 16, or a radiation source, is provided to selectively heat one of the electrodes of the sensor, for example Figure 1 The method further comprises determining 220 a current flux between electrodes of the electrochemical sensor. The current flux is based on a voltage caused by selectively heating one electrode by a heat source or by selectively irradiating one electrode by a UV light source. The method further comprises determining 230 the activity of the sensor based on a signal shape of the current flux.

[0048] Figure 2b 1 shows a schematic block diagram of an embodiment of a corresponding control device 20 for determining the electrode activity of an electrochemical sensor. Figure 1 In conjunction with the control device 20 described above, for example, the control device may include an interface 22 and one or more processors 24 coupled to the interface. Here, the functions of the control device may be provided by one or more processors, wherein the detection and output of signals such as for and / or by the electrode, heat source or output device are performed via the interface. The control device 20 is configured to perform Figure 2a In this respect, the function of the control device will also be explained below with reference to this method. In general, the method can be performed, for example, by a device comprising an electrochemical sensor and a heat source, for example by a control device of the device. In this case, the device can be, for example, a breath alcohol measuring device.

[0049] The method comprises: activating 210 a heat source within a predetermined time period to selectively heat one of the electrodes of the sensor. Activating the heat source may, for example, comprise providing a control signal to the heat source or to a power source of the heat source to activate the heat source. Alternatively, activating the heat source may comprise: providing power to the heat source, for example when sufficient current can be supplied to the heat source directly from a control device. For example, it may be the case that the heat source is an LED that can operate at a power of several watts. In some embodiments, a thermal effect may be used to generate a voltage between the electrodes. Additionally or alternatively, a photoelectric effect may be used. Thus, the heat source may be controlled so that in order to generate a voltage between the electrodes, one of the electrodes is excited thermally by the heat source within a predetermined time period or also photoelectrically, for example by emitting light onto the one electrode.

[0050] The method further comprises determining 220 a current flux between electrodes of the electrochemical sensor. Figure 1 As described in conjunction with the above, the current flux is based on the voltage caused by the selective heating of the one electrode by the heat source. The current flux can be determined in this case in a measuring mode of an electrochemical sensor device, which includes an electrochemical sensor, similarly to the measurement of the current between the measuring electrode and the counter electrode. In this case, the measured current can be recorded via a plurality of sampling points (samples) and stored in a memory, such as a memory of a control device, for subsequent analysis.

[0051] Furthermore, the method comprises determining 230 the vitality of the sensor based on the signal shape of the current. The signal shape of the current flux can be determined here, for example, based on a plurality of recorded sampling points. Thus, determining the vitality of the sensor can comprise determining the signal shape based on a plurality of recorded sampling points of the measured current. If the signal shape is available, one or more parameters of the signal shape can be analyzed to determine the vitality of the electrochemical sensor.

[0052] The parameter is related to the length of time required for the generated voltage to decrease again. Thus, the vitality of the sensor can be determined based on the time interval between a first moment when the voltage is generated and a second moment when the current flux drops below the threshold value after the voltage has been generated. In this case, the time interval can indicate the vitality of the electrode. The shorter the time interval, the "faster" the electrochemical sensor is and the higher the vitality of the sensor.

[0053] Additionally or alternatively, the shape of the signal peak can be used to determine the activity of the sensor. For example, the activity of the sensor can be determined based on the height or steepness of the signal peak in the signal shape. The higher the signal peak, or the steeper the signal peak, the higher the activity of the sensor. Alternatively or additionally, the part of the signal shape after the signal peak can be taken into account. An electrochemical sensor with high activity can be identified, for example, by the fact that the signal peak is followed by an undershoot, which is not visible in a dry electrochemical sensor. Therefore, the activity of the electrode can be determined based on the undershoot in the signal shape after the signal peak in the signal shape.

[0054] In various embodiments, the method further comprises: providing 240 information about the vitality of the sensor via a graphic output unit. Various implementations of the graphic output unit have been combined herein. Figure 1 Introduced. In particular, the graphic output unit can be a screen, a seven-segment display or a graphic output unit based on one or more LEDs. The information about the vitality of the sensor can here represent the vitality of the sensor in different ways. In a first implementation, the information about the vitality of the sensor can indicate whether the electrochemical sensor is sufficiently energetic (and thus sufficiently accurate or fast enough to be used in field operation). In this case, the information about the vitality of the sensor can be displayed, for example, via a single LED (where, for example, the green light of the LED means that the electrochemical sensor is sufficiently energetic, and the red light of the LED means that the electrochemical sensor is no longer sufficiently energetic). In another implementation, more than two states can be distinguished. Thus, for example, the information about the vitality can indicate one of three states - good, medium or poor, or "no defect", "still sufficient vitality (but no longer defective)", "no longer sufficient vitality". In this case, the corresponding information about the vitality can also be output via an LED (such as "green", "yellow", "red") or via the screen of the device. The vitality of the sensor can also be output via the screen of the device in the form of a percentage display or a bar graph. For example, if the vitality of the electrode violates a threshold value, for example if the status is "still sufficiently vital" or "no longer sufficiently vital", or if a calculated percentage value violates a threshold value, the output may be provided. In other cases, no output may be provided. In a different implementation, the vitality recognition may be performed on-site, wherein in the case of a weak sensor, a warning may be given to the customer in a timely manner in the sense of preventive maintenance. For example, a regular vitality check may be performed, for example at device startup.

[0055] In some embodiments, in addition to information about the current vitality of the sensor, the information about the vitality may also include information about a prediction of the course of change of the vitality. Such a prediction may be useful because the vitality of the sensor has an impact on the accuracy of the sensor - if only the vitality of the sensor changes, the estimated accuracy will also change. Therefore, based on the prediction, it can be determined how long the sensor still has sufficient accuracy, taking into account a preset minimum measurement accuracy. For example, the signal shape can be used to determine not only the current vitality of the sensor, but also how long the sensor still has sufficient vitality. To this end, determining 230 the vitality of the sensor may include: predicting the vitality of the sensor, for example based on the change of the signal shape and the corresponding determined sensor vitality in multiple measurements, wherein the multiple measurements are performed, for example, over several days, weeks or months. For example, predicting the vitality of the sensor may include performing a time series prediction based on the change of the sensor vitality in multiple measurements. For this purpose, a fitting algorithm may be used, for example. Based on the prediction, it can be determined how long the sensor is expected to be used, taking into account a preset minimum measurement accuracy. For example, a lookup table can be used to infer a prediction of the estimated accuracy of the electrochemical sensor from the prediction of the vitality of the sensor. The estimate can then be compared with the preset minimum measurement accuracy. Thus, the information about the vitality of the sensor can include information about the estimated remaining duration of the electrochemical sensor taking into account a preset minimum measurement accuracy. Here, the information about the estimated remaining duration of availability can have a granularity of several months, for example, and the estimate can also be interpreted conservatively. For example, the information about the estimated remaining duration of availability can indicate that the electrochemical sensor is still available for at least the displayed number of months before the electrochemical sensor must be maintained or replaced. Here, the output can also be provided if the estimated remaining duration is less than a threshold value.

[0056] In some embodiments, the determined vitality of the sensor can also be used to adjust the measurement results performed by means of the sensor, and thus improve the accuracy. As already introduced above, the accuracy of the sensor depends on the vitality of the sensor. Here, in many cases there is a correlation between the vitality of the sensor and the deviation of the measurement result. For example, the deviation can be subject to the type of structure-if the vitality of the sensor is known, a compensation parameter can be calculated from it to compensate for this deviation. Therefore, the method can include determining 250 compensation parameters based on the vitality of the sensor. The compensation parameter can describe the extent to which the vitality of the sensor affects the measurement of the sensor. Therefore, the adjustment of the compensation parameter can be performed to improve the accuracy. Thus, due to the improved accuracy, longer calibration intervals can be achieved. For example, the compensation parameter can describe the above-mentioned deviation. In this way, the compensation parameter can be calculated, for example, based on the determined vitality, such as based on a mathematical function or based on another query table. In addition, the method can include performing 255 measurements with the aid of an electrochemical sensor taking into account the compensation parameter. Here, the measurement result of the measurement can be based on the compensation parameter. By using the proposed scheme, the vitality parameter can be determined on the spot, and the compensation parameter required for evaluating the measurement result of the alcohol measurement can be adjusted. The accuracy of the measurement is thus improved. Furthermore, the improved accuracy can be used to calculate the estimated remaining duration of usability of the electrochemical sensor. Thus, the calibration interval can also be extended. In some embodiments, the accuracy can also be determined on-site without alcohol, or the calibration can be tracked on-site, for example based on compensation parameters.

[0057] The determination of the vitality can be triggered by different motives. For example, the determination of the vitality can be performed at regular moments, for example when the device is started. Here, for example, the determination of the vitality can be part of a self-test of the device. In other words, the method can be performed by the device, which includes an electrochemical sensor and a heat source and correspondingly includes a control device. The method, such as determining the vitality of the sensor, can be formed as part of a self-test of the device. The self-test of the device can be performed, for example, when the device is started or at the request of a user of the device.

[0058] In some embodiments, the determination of the vitality can also be used to determine whether the sensor is correctly connected and functioning. This can be achieved, for example, by means of a functional test, in which it is checked whether a potential can be established between the electrodes and whether a current flux can be measured between these electrodes. In addition, the proposed solution can replace physical sensor identification, for example by evaluating the sensor response to a voltage pulse. Here, the present invention is not limited to alcohol sensors, but the present invention can also be applied to other electrochemical sensors. The method may include performing a functional test on the electrochemical sensor, wherein the functional test is based on determining the vitality of the electrodes. If it is determined that a current flux is measured between the electrodes when determining the electrode vitality, it can be considered that the functional test is passed.

[0059] For example, the interface 22 may correspond to one or more inputs and / or one or more outputs for receiving and / or transmitting information, such as in the form of digital bit values ​​based on code within a module, between modules, or between modules of different entities.

[0060] In an embodiment, one or more processors 24 may correspond to any controller or processor or programmable hardware component. For example, the functionality of one or more processors 24 may also be implemented as software programmed for the corresponding hardware component. Any processor, such as a digital signal processor (DSP), may be used herein. The embodiments are not limited to a specific type of processor herein.

[0061] Before combining, for example Figure 1 The schemes or examples described in the foregoing describe more details and aspects of the method and control device. The method and control device may include one or more additional optional features corresponding to one or more aspects of the proposed schemes or described examples as described above or below.

[0062] Laboratory measurements were performed to validate the method. For this purpose, a device was built to record the raw values ​​of the electrochemical sensor and to operate a blue LED. The LED has been placed over the EC sensor and operated in a current-controlled manner at a reduced power, for example 500 mA, for exactly 1000 ms. This irradiation causes a change in the measured value of the chemical sensor due to the thermovoltage.

[0063] In the first test, measurements were taken on healthy sensors. Figure 3a The measured values ​​300 of a healthy electrochemical sensor 300 in an exemplary test setup are shown. The sensor clearly reacts to the irradiation. After less than a second, the edge of the decay has already crossed the zero line. In addition, a characteristic undershoot can be seen.

[0064] For another experiment, the electrochemical sensor was artificially dried. Subsequently, measurement values ​​310 of a healthy (alive) electrochemical sensor and measurement values ​​320 of a dried electrochemical sensor were generated. Figure 3b The measured values ​​of two sensors are shown.

[0065] The dry sensor shows a significantly changed behavior. The signal peak of the current is reduced. The falling edge has become significantly slower. The undershoot is no longer visible. Based on the dynamics of these changes, a slow sensor can be identified.

[0066] Following the test, the sensor was inflated again with dry gas containing approximately 380 µg / l of ethanol. Figure 3cA comparison of the ethanol curve 330 of a live sensor and the ethanol curve 340 of a dry sensor is shown. The dry sensor becomes significantly slower due to drying, but is still able to make measurements.

[0067] In another test, a soldering iron was used as a heating source. Due to its high temperature, for example 400°C, the soldering iron radiates a considerable part of its energy as thermal radiation. Instead of an LED, the soldering iron was briefly held without contact over the electrochemical sensor. The LED peak (peak point) differs from the soldering iron peak here. The soldering iron peak consists of two superimposed peaks. In the test device, these are not as high as the LED peaks, which also drop faster than the soldering iron peaks. Figure 4 The measurement results of the test setup are shown. Here, the peak 410 is the LED peak and the subsequent peak 420 is the peak caused by the soldering iron. The reason for the signal shape may be that the first fast peak is the result of the IR radiation entering the sensor and causing a temperature rise at the electrode surface. The second peak may be the result of the heating of the sensor housing and the subsequent slow heat conduction. This effect is still valid even if the soldering iron has long been removed again. In contrast, most of the LED radiation penetrates the sensor and reacts directly at the electrode surface, i.e. inside the sensor. Here, a thermoelectric voltage is induced due to the temperature increase. Slow heat conduction effects do not occur. This shows the advantages when using LEDs as radiation sources.

[0068] In another experiment, the housing of the electrochemical sensor was essentially opaque and then illuminated with an LED. In a repeated experiment, only a small portion of the LED light could enter the sensor; instead, the housing heated up. In this case, only slight differences between heating by the soldering iron and heating by the LED could be seen in the corresponding measurements. In this case, the peak height of the LED peak was significantly reduced, and the total duration was increased.

[0069] More details and aspects of the scheme are combined with the previous Figures 1 to 2b The scheme or example described is described. Embodiments of the scheme may include one or more additional optional features corresponding to one or more aspects of the proposed scheme or described example, as described before or after.

[0070] with one or more of the previously detailed examples and appendices Figure 1 The aspects and features described above may also be combined with one or more other examples to replace the same features of another example or to additionally introduce the features into another example.

[0071] In addition, the example may be or relate to a computer program having a program code, which executes one or more of the above methods when the computer program is executed on a computer or processor. The steps, operations or processes of the different methods described above can be performed by a programmed computer or processor. The example may also include a program storage device, such as a digital data storage medium, which is readable by a machine, a processor or a computer and encodes a machine-executable, processor-executable or computer-executable program of instructions. The instructions execute some or all of the steps of the method described above or cause them to be executed. The program storage device may, for example, include or be a digital memory, a magnetic storage medium such as, for example, a disk and a tape, a hard drive or an optically readable digital data storage medium. Other examples may also include a computer, a processor or a control unit, which is programmed to perform the steps of the above methods, or may include a (field) programmable logic array ((F) PLA=(Field) Programmable Logic Arrays) or a (field) programmable gate array ((F) PGA=(Field) Programmable Gate Arrays), which is programmed to perform the steps of the above methods.

[0072] The functions of the various elements shown in the drawings, including any functional blocks referred to as "mechanisms", "mechanisms for providing signals", "mechanisms for generating signals", etc., may be implemented in the form of dedicated hardware, such as "signal providers", "signal processing units", "processors", "controllers", etc. and as hardware capabilities for executing software in conjunction with associated software. When provided by a processor, the functions may be provided by a single dedicated processor, a single commonly used processor, or a plurality of separate processors, some or all of which may be used in common. However, the term "processor" or "controller" is not limited to hardware specifically capable of executing software, but may include digital signal processor hardware (DSP hardware; DSP=Digital Signal Processor), network processors, application specific integrated circuits (ASIC=Application Specific Integrated Circuit), field programmable gate arrays (FPGA=Field Programmable Gate Array), read-only memories (ROM=Read Only Memory), random access memories (RAM=Random Access Memory) and non-volatile storage devices (memory) for storing software. Other hardware, conventional and / or custom hardware, may also be included.

[0073] For example, a block diagram may represent a rough circuit diagram that implements the principles of the present disclosure. Similarly, a flow chart, sequence diagram, state transition diagram, pseudo code, etc. may represent various processes, operations, or steps, which are, for example, substantially represented in a computer-readable medium and thus executed by a computer or processor, whether or not such a computer or processor is explicitly shown. The methods disclosed in the specification or claims may be implemented by components having mechanisms for performing each of the various steps of the method.

[0074] It should be understood that the disclosure of multiple steps, processes, operations or functions disclosed in the specification or claims should not be interpreted as being in a specific order unless explicitly or implicitly indicated differently, such as for technical reasons. Therefore, the disclosure of a step or function by multiple steps or functions is not limited to a specific order unless these steps or functions are not interchangeable for technical reasons. In addition, in some examples, a single step, function, process or operation may include and / or be decomposed into multiple sub-steps, functions, processes or operations. Unless these sub-steps are explicitly excluded, such sub-steps may be included and are part of the disclosure of the single step.

[0075] Furthermore, the following claims are hereby incorporated into the detailed description, where each claim can stand on its own as a separate example. Although each claim can stand on its own as a separate example, it should be noted that although a dependent claim in the claims may refer to a specific combination with one or more other claims, other examples may also include a dependent claim combined with the subject matter of any other dependent or independent claim. Such combinations are expressly suggested herein, and no specific combination is intended unless otherwise stated. In addition, features of a claim are also included for any other independent claim, even if the claim is not directly dependent on the independent claim.

Claims

1. A method (200) for determining the viability of an electrode of an electrochemical sensor in an electrochemical sensor device, the method comprising: activating a heat source for a predetermined period of time to selectively heat one of the electrodes of the sensor; determining a current flux between electrodes of the electrochemical sensor, wherein the current flux is based on a voltage caused by the heat source selectively heating the one electrode; as well as Based on the signal shape of the current flux, the activity of the sensor is determined.

2. The method according to claim 1, Also includes: Information about the activity of the sensor is provided via a graphical output unit.

3. The method according to claim 2, The information about the vitality of the sensor comprises information about an estimated remaining duration of availability of the electrochemical sensor taking into account a predefined minimum measurement accuracy.

4. The method according to any one of claims 1 to 3, The method is performed by a device comprising the electrochemical sensor and the heat source, wherein the method is performed as part of a self-test of the device.

5. The method according to any one of claims 1 to 3, further comprising: A compensation parameter is determined based on the activity of the sensor, wherein the compensation parameter describes the extent to which the activity of the sensor affects the measurement of the sensor, wherein the method further comprises performing a measurement by means of the electrochemical sensor taking into account the compensation parameter.

6. An electrochemical sensor device (10) for use in a breath alcohol measuring apparatus (100), the electrochemical sensor device comprising: An electrochemical sensor having at least two electrodes (12; 14); and Heat source (16); Control device (20); The invention is characterized in that the heat source is arranged so that when activated, the heat source selectively heats one of the electrodes (12) of the electrochemical sensor, The control device is designed to determine the activity of the electrode based on the selective heating of the one electrode, ie based on the voltage generated between the electrodes by the selective heating and the current flow generated thereby.

7. The electrochemical sensor device according to claim 6, The heat source is a light emitting diode (LED).

8. The electrochemical sensor device according to claim 6 or 7, The control device is designed to carry out the method according to claim 1 .

9. The electrochemical sensor device according to claim 6 or 7, comprising: A graphic output unit is provided to output information about the activity of the sensor, wherein the information about the activity of the electrode is determined based on the selective heating of the one electrode.

10. A breath alcohol measurement device comprising an electrochemical sensor arrangement according to any one of claims 6 to 9.

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