TECHNICAL FIELD

The field of this Invention relates generally to systems for analyz¬ ing breath samples of humans. More particularly, this Invention re¬ lates to systems employing a person's breath sample to develop both a (1) breath signature signal for identifying certain characteristics of the person and (2) an alcohol signal produced by detecting the presence of alcohol.

BACKGROUND ART

As background , the Applicant notes that various schemes have been devised for analyzing human breath samples to obtain information about a person, particularly information relating to the person's percent blood alcohol concentration (BAC ) . However , shortcomings and deficiencies still exist in the technology.

Specifically, existing breath analysis techniques simply do not provide approaches for gathering information other than BAC about the person from a breath sample. Examples of existing technology are dis- cussed below .

U. S . Patent 4, 093, 945 to Collier et al discloses a breath testing system for alcohol intoxication breath testing. The system includes (1) a breath input unit, (2) a controller which delivers a sample of deep lung breath to (3) an evaluator including an alcohol detector and an output apparatus. The controller includes a breath flow sensing means to insure that a deep lung breath sample is tested. A passing signal

to insure that a deep lung breath sample is tested. A passing signal cannot be obtained unless (a) the predetermined continuous and unin¬ terrupted flow has occurred, and (b) the resulting sample tests below a predetermined flow value. U. S . Patent 4, 317, 453 to Heim et al discloses a system for test¬ ing a person's breath for the determination of its alcohol content. The system first determines when the breathing air is at a condition in which breath testing results will be effected. This is done by arrang¬ ing a capacitor in a breathing tube through which the breathing air is detected.

First, the capacitor is heated to a predetermined temperature. Then the breathing air is directed over it so as to cool the capacitor until it has attained a predetermined temperature change. This tem¬ perature change is such that it will take place when the person's breathing air has its desired consistency.

When this occurs, the breathing air is then directed into a test chamber, in which it is tested to determine the constituency of the breathing air, particularly the percentage of alcohol which it contains. The device for testing the person's breath also contains a test chamber connected to the tube with a control means. This control means senses the temperature of the capacitor and then permits the flow of the gas into the test chamber only after a predetermined temperature drop has occurred.

U. S. Patent Application with Serial Number 06/494, 301, filed May 13 , 1983 by Brian P. Elfman and Lawrence T. Rojahn, now abandoned, discloses an apparatus for measuring the blood alcohol concentration (BAC) of an individual. The apparatus includes (1) a gas vapor sen¬ sor for receiving and analyzing the alcohol concentration in the breath of the individual, (2) an analog-to-digital converter, and (3) a gas analyzer for detecting the rate of change of the signal generated by the sensor.

When the rate of change of the signal is at or near zero, thereby indicating the breath is deep lung air, the sensor signal is transposed to a BAC reading in the BAC look-up table. The BAC read- ing is then compared to a pre-recorded level obtained from a memory, to determine the intoxication level of the individual. A flow sensor can be provided to assure that the individual is expelling a sufficient

volume of air to assure a good reading. An auto ignition gate can be provided to disable a vehicle if the individual is found to have a BAC reading above a predetermined level which indicates intoxication.

While the above technology does offer laudable approaches and solutions with respect to the particular situation each addresses, none of them individually or in combination disclose or suggest the Invention defined in the appended Claims of this present case. Specifically, the following problems persist despite the efforts of the existing technol¬ ogy. All the above approaches are specifically directed to determining the BAC of a person in order to prevent that person from operating a vehicle if he is inebriated. No additional information can be determined by these systems from the breath sample. These systems are not sophisticated enough to accurately and reliably screen users to ensure that only an authorized person is tested.

Existing breath analyzing equipment, to provide a breath sample test result which can be introduced into evidence in a drunk driving prosecution, (a) must be built to very precise specifications, (b) are large and not easily transportable, and (c) are sensitive and thus require frequent servicing in order to remain precisely calibrated. As a result, the available equipment is quite expensive.

Because the accurate equipment is not easily transportable, an arresting police officer faces a race against time in getting an in¬ ebriated person to the equipment's location quickly enough that a person's body does not metabolize the alcohol prior to a BAC test.

Additionally, these systems have difficulty in accurately detect¬ ing attempts to deliver bogus breath samples to them , for example in the case where inebriated person #1 has a breath sample delivered by a sober person #2. The opportunity also exists to introduce a bogus breath sample originating in a compressed air bottle or having been fil¬ tered prior to being subjected to a BAC test.

These are only a few of the problems which have not been adequately resolved by the existing technology. Because of these problems, it became necessary to devise the Invention (1) disclosed by example below, and (2) defined in the appended Claims.

DISCLOSURE OF THE INVENTION

Solutions and advantages are offered by this Invention which resolve many of the deficiencies still present in the existing technology.

Broadly summarized, the Invention is a system for analyzing a breath sample, the apparatus comprising the following six (6) elements:

(1) means for sensing the pressure, the temperature and the humidity of the breath sample and in response generating a breath sig¬ nature signal;

(2) means for sensing the alcohol content, if any, of the breath sample and in response generating an alcohol signal;

(3) means providing a breath reference;

(4) means providing an alcohol reference which includes an al¬ cohol threshold level;

(5) means for comparing the breath signature signal with the breath reference and in response generating one of (i) a valid signal if the breath signature signal substantially matches within a pre-selected range or envelope and (ii) an invalid signal if the breath reference sig¬ nal does not substantially match the breath reference within the pre¬ selected range or envelope; and (6) means for comparing the alcohol signal with the alcohol reference and in response generating one of (i) a passing signal if the alcohol signal is less than the threshold level and (ii) a failing signal if the alcohol signal equals or exceeds the threshold level.

Additional features offered by this Invention, but not sum- marized above are (1) described by example below and (2) defined and scoped in the appended Claims.

This Invention expands and improves the technology of breath analysis, to thereby permit the control and acquisition of new and more sophisticated information about the person giving the breath sample. A key feature and advantage of this Invention is that, on the basis of a single breath sample from a particular person, a breath sig^ nature signal can be generated for that particular person.

This Invention employs a simple, sophisticated and inexpensive transducer to measure the temperature, pressure and humidity of a breath sample. The transducer then integrates these values together to produce a single output breath signature signal in the form of a frequency spectrum for the person delivering the sample.

, Previously existing technology requires complex apparatus to measure temperature, pressure and temperature together; these values are then manipulated by complex mathematical formulas to obtain infor¬ mation about the breath sample. Complex flow meters are used to en- sure delivery of a deep breath sample. The only value measured by existing technology is the BAC, and that is measured with a chemical sensor.

In contrast, this Invention performs a simple joint measurement of temperature, pressure and humidity combined, integrates this measurement, and produces as an output the breath signature signal. This is done in addition to measuring the alcohol in this breath sample.

This Invention is rugged, accurate, reliable, easily calibrated and supplies breath sample information that can be used by the prosecution in a drunk driving adjudication. When installed in a vehicle and interlocked into the vehicle's ignition system, it would be impossible for an inebriated person to start the vehicle.

Other advantages offered by this Invention are described by ex¬ ample below and defined by the appended Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 schematically shows how the Invention processes breath sample information; Fig. 2 is a hardware schematic diagram;

Fig. 3 shows an alternative comparator arrangement; Fig. 4 illustrates breath sample analysis; and

Figs. 5 and 6 illustrate installation of the inventive apparatus in an automobile.

BEST MODE OF CARRYING OUT THE INVENTION

This Detailed Description, which incorporates the accompanying Drawings briefly described above, offers specific examples (i.e. , embodiments) of how to practice the Invention, but it does not actually define the Invention. Instead, the Invention is defined by the num-

bered paragraphs of the appended Claims. This Detailed Description sets forth the best modes presently contemplated by the Inventor for making and using the claimed Invention. Further, this Detailed

Description is intended for facilitating, through example, the under- standing of the Invention defined in the Claims.

Fig. 1 shows an Overview of method and apparatus 20 for analyzing a breath sample 22. Included is a first means 24 for sensing the temperature, the pressure and the humidity of the breath sample

22, and in response generating as an output a breath signature signal 26.

Also included is a second means such as sensor 28 for sensing the alcohol content if any of the breath sample 22 , and in response generating an alcohol signal.

A third means such as breath reference 32 is stored in computer memory for providing a breath reference. A fourth means, e. g. an al¬ cohol reference 34, is stored in computer memory for providing an al¬ cohol reference and includes an alcohol threshold level 36 , in this case established at 0.025% BAC.

A fifth means, for example a first comparator 38, is used for comparing the breath signature signal ^« 26 with the breath reference 32. In response, comparator 38 generates either (1) a valid signal, shown as a plus sign enclosed in a circle and indicated as a "yes" with a reference numeral 40, of the breath signature signal ^' 26 substantially matches within a pre-selected range (shown in Fig. 1 as a passing en- velope 42) stored in breath reference 32; or (2) an invalid signal, shown in Fig. 1 as a minus sign enclosed in a circle indicating a "no" and labeled with reference numeral 44, if the breath signature signal 26 does not substantially match the breath reference 32 within the pre¬ selected range of 42. Finally included is a sixth means, for example a second com¬ parator 46 , for comparing the alcohol signal 30 with the alcohol reference 34. In response, comparator 46 generates one of the following: (1) a passing signal shown as a plus sign enclosed in a circle indicating a "yes" and labeled with reference numeral 48, if the alcohol signal 30 is less than the threshold level 36 ; or (2) a failing signal, shown as a minus sign enclosed in a circle and labeled with a reference numeral 50 , if the alcohol signal 30 equals or exceeds the

threshold level 36.

In addition, System Details offer other features and structures which are provided by this Invention to further enhance its usefulness. These System Details are fully described below . The Invention has a seventh means, shown as a computer memory 52, storing certain test results performed by the breath analysis. These test results include the breath signature signal 26 , the alcohol signal 30, the response of the fifth means (comparator 38) in comparing the breath signature signal with the breath reference 32, the response of the sixth means (comparator 46) in comparing the alcohol signal with the alcohol reference 34, and the date and time when breath sample 22 was analyzed. A time clock 54 and a date clock 56 provide the respective time and date of the performance of each breath analysis. Further included can be an eight means for preventing the use of apparatus 20 by an unauthorized person. In one case, this function is provided by a ^* keyboard 58 having number keys for inputting a Per¬ sonal Identification Number (PIN) . This PIN is coupled to a "recognize PIN" component 60 within the system's controller electronics, for iden- tifying a user as being a valid user. This eighth means is expandable to include use of the validity test results performed by comparator 38 to confirm that a valid breath sample is analyzed by transducer 24 and sensor 28.

The ninth means, for example a digital display unit 62, is employed for numerically displaying alcohol signal 30 and the sixth means (comparator 46) response (i.e. , "P" for "Pass" and "F" for "Fail") in comparing alcohol signal 30 with alcohol reference 34.

A grouping of first, second, third and fourth respective status lights 64 , 66 , 68 and 70 serve as a tenth means for displaying a plurality of status indicators regarding the apparatus 20 and the breath sample 22. The status indicators include a plurality of differently colored lights which variously cycle to being in the states of "steady on" , "flashing on" , and "steady off".

The colors selected for these lights are red, green, amber and blue. At the beginning of a test sequence, all lights are off. The am¬ ber light is then activated into the "flashing on" state; the system is checking itself to make sure that it is operating correctly for taking a

test. If the blinking continues, it means a test can be taken, but the system needs to be checked because of some malfunction, for example to replace a power supply. However, if the amber lights goes to a "steady on" condition, then the system is malfunctioning and no test can be properly taken. If the system is operating correctly, the amber light will then move to the "steady off" condition to indicate that the system is functioning properly.

Next, the blue light begins blinking, to indicate that apparatus 20 is preparing itself for taking a test. This can take anywhere from about five (5) seconds to about sixty (60) seconds, depending on such conditions as when the last test was taken, the state of the power supply, and the temperature. When the system is ready to accept a test, the blue light changes to the "steady on" condition. Then, at the end of a test, the blue light goes to the "steady off condition to indi- cate that a sufficient breath sample has been delivered to permit an adequate test.

If the test passes, then the green light achieves a "steady on" condition. Conversely, if the breath sample fails, the red light cycles to the "steady on" condition. A power supply 72 serves as an eleventh means for supplying power to the apparatus 20.

A sampler 74 serves as a twelfth means for receiving the breath sample 22. Sampler 74 comprises a housing 76 formed to be grasped in the hand (not shown) of a person, and transported to the mouth (not shown) of the person who is to deliver the breath sample 22, the twelfth means (sampler 74) defining within itself a hollow chamber 78 for receiving the breath sample 22.

Twelfth means 74 further includes a mouthpiece 80 which is removably mountable to the housing 76 to be in fluid communication with the chamber 78. The mouthpiece 80 includes an integral trap 82 for removing moisture and particulate matter (not shown) if any entrained in the breath sample as the breath sample moves from the person toward the chamber 78.

An ignition enable 84 is a switch which functions as a thirteenth means for interlocking the apparatus 20 into a starter system or ignition

86 of an engine 88 of a powered machine. The thirteenth means igni¬ tion 84 is formed to prohibit operation of the starter system or ignition

86 unless both of the following occurs: (1) the response generated by the fifth means comparator 38 , when comparing the breath signature signal 26 with the breath reference 32, is a valid signal; and (2) the response generated by the sixth means comparator 46, when comparing the alcohol signal 30 with the alcohol reference 34, is a passing signal. A detector 90 is a fourteenth means for coupling the apparatus 20 to a powered machine or engine 88 to detect one of (1) the machine is operating and (2) the machine is not operating.

Security hardware 92 serves as a fifteenth means for installing the apparatus 20 in a vehicle so the apparatus is accessible for a per¬ son to deliver a breath sample while being sufficiently secure to inhibit tampering with the apparatus by the person. A fiber optic cable 94 is coupled between a light emitter 96 and a light receiver 98. These three items are recessed below the surface of sampler 74. Screws 100 are each penetrated by a hole 102 defined in the screw neck. If an attempt is made to unscrew screw 100 , hole 102 will pass light through fiber op¬ tic cable 94 so detector 98 will indicate that sampler 74 has been breached. This security hardware system 92 can be used to secure all pieces of apparatus 20 into a powered vehicle. Another means for security installation of the apparatus in a vehicle is to separate the apparatus into sub-systems or components which are isolated from one another. In a vehicle 104 , some components are mounted on a dashboard 106, including sampler 74, display 62 , and cradle 108 for holding sampler 74 when not in use. In Fig. 5 the com- ponents are drawn with solid lines.

Other components are installed behind the dashboard so they are isolated from a user. These components are drawn in Fig. 6 as dashed boxes and dashed lines. A junction box 110 serves as a switch for communicating the components with each other. Sampler 74 is coupled with a visible cable 112 to a port 114 provided to penetrate dashboard

106 for coupling sampler 74 to junction box 110. As is typical, an igni¬ tion switch 116, operable by a key, is recessed into the automobile's steering column below a steering wheel 118. A hidden cable 120 couples ignition switch 116 to junction box 110. Hidden cables 122, 124 and 126 respectively connect junction box 110 to ignition 86 , the controller electronics 128 for operating apparatus 20, and 72 which in this case is a 12 volt rechargeable automobile battery.

Fig. 5 shows the system components of apparatus 20, and the parts of automobile 104 with which the components interact, as solid lines. As Fig. 5 illustrates, electronics 128 can also b installed behind the rear passenger seat 130 in front of trunk compartment 132. Alter- natively, electronics 128 can be installed beneath the floor surface of trunk compartment 132. In Fig. 6 , digital display 62 is coupled to junction box 110 through a cable 143. In Fig. 5 , a cable 136 would connect respective controller 128 to junction box 110.

Keyboard 58 (Fig . 2) , besides having number keys typical to hand-held calculators, includes additional button keys 138 labeled respectively with letters A, B and C . These buttons can be reserved for adding additional system features in the future as desired. Presently it is contemplated that one button, for example C, will be provided to permit a user to "clear" an incorrect entry through keyboard 58. In controller 128, a clear circuit 140 will be provided to accomplish this function.

It is contemplated that the Fig. 1 power supply 72 will be imple¬ mented as shown in Fig. 2 with 1 12 volt DC car battery 142 and a rechargeable standby plus or minus 6 volt DC sealed lead acid battery, respectively coupled through a cable 144 and a cable 146 to junction box 110. The electronics in controller 128 would include a battery con¬ trol 148 logic that would permit charging of both batteries from engine 88 when detector 90 senses engine 88 is operating. Detector 90 can be coupled, e. g. through a cable 150, to an alternator 152 coupled to en- gine 88.

The 6 volt SLA battery is labeled with reference numeral 154. Batteries 142 and 154 are interconnected in such a way to each other and to controller 128 so battery control 148 ensures that car battery 142 is never connected directly to controller 128. Battery 142 must be electrically isolated from controller 128 so a power surge will not burn up controller 128 or the other electronic components.

Controller 128 electronics include a microprocessor 156, also known as a Central Processing Unit (CPU) , for controlling the logical operations. CPU 156 is coupled to a status light control 158 for operat- ing status indicator lights 64, 66 , 68 and 70. A breath reference range adjust 160 is included to permit the envelope or range of deviations from the breath reference to be changed, to thereby make the sen-

sitivity of breath reference 32 greater or lesser; the breath signature signal 26 will pass or fail depending on how closely it is forced to match the breath reference.

A personal identification number (PIN) register 162 is coupled to microprocessor 156 for comparison with the PIN keyed in by the user on keyboard 58. A read out control 164 is accessible through microproces¬ sor 156 to print out or otherwise display the memory results 52 to a results read out display 166.

In one construction, transducer 24 comprises a thin film of sub- stantially dielectric material 168 sandwiched between a first electrical conductor 170 and a second electrical conductor 172. For this applica¬ tion, transducer 24 has been fabricated from Kynar Piezo film, a spe¬ cially processed polyvinylidene fluoride (PVDF) that purportedly ex¬ hibits the highest piezoelectric and pyroelectric properties of any known plastic. Kynar is a registered trademark of Pennwalt Corporation, 900 First Avenue, King of Prussia, PA, USA 19406.

Fig. 3 shows an alternative construction of comparators which somewhat differs from the Fig. 1 arrangement of first comparator 38 and second comparator 46. In Fig 3 , the first comparator is in the form of an electronic fil¬ ter 174 in which the breath reference 176 having permissible ranges of deviations shown as envelope 42 being stored in filter 174. The sen¬ sitivity of filter 174 can be changed with envelope adjust 160 to expand or narrow envelope 42. In operation, the breath signature signal 26 from transducer 24 is essentially matched against breath reference 176. If signal 26 falls within envelope 42, signal 26 will be seen as a "valid" signal 178. Valid signal 178 trips an enable switch 180, which generates and sends an "okay to test" signal 182 to turn on comparator 146. Second com- parator 46 then operates as previously described.

However, if filter 174 determines that signal 26 is invalid, an invalid signal 184 is issued, which causes the system to stop and there¬ fore not permit ignition enable 84 to function. Ignition 86 cannot be operated. Fig. 4 illustrates the analysis of a breath sample.

Beginning at time equals zero, a person begins breathing into mouthpiece 80. In Region 1 , labeled with reference numeral 186,

transducer 24 generates breath signature signal 26 for matching in com¬ parator 38 against breath reference 32 to determine whether or not this is a valid sample. In typically lest than one second, and on the average within about 100 milliseconds, first comparator 38 makes this determination.

In Region 2, labeled with reference numeral 188, sensor 28 measures the alcohol content of the breath sample and generates alcohol signal 30. At knee 190 of breath curve 192 the sampling is complete. The results are stored in computer memory, and second comparator 46 determines whether or not the breath sample passes. A pass signal is delivered to the ignition enable 84 , which permits a vehicle to be started. A fail signal 196 prohibits starting of the vehicle.

On average, about 2.5 to 4.0 seconds will elapse from beginning to end of a test; in some cases may take up to ten (10) or twenty (20) seconds (e. g. , someone with emphysema) .

As illustrated in Fig. 2 , controller electronics 128 can be ex¬ panded as shown with dashed line 198 to encompass components which initially are not integral to the controller. For example, ignition inter¬ lock control 84, standby battery 154 and detector 90 can be directly coupled to controller 128 through respective cables 200, 202 and 204. With this arrangement, these components would not be coupled to junc¬ tion box 110.

In both versions of the controller, a junction box controller is included, shown as reference numeral 206 , to permit microprocessor 156 to control the routing function of junction box 110.

Viewed from a slightly different standpoint, the Invention offers an apparatus 20 for performing a test of a breath sample 22 delivered to a sampler 74 by a person (1) to determine a measure of the alcohol content if any of the breath sample, and (2) to determine one of (i) the alcohol content is less than a predetermined threshold level 36 and thus the breath sample is a passing sample and (ii) the alcohol content is greater than the threshold level 36 and thus the breath sample is a fail¬ ing sample.

The apparatus comprises a first comparator 38 which performs a validity test, to thereby function as a first means for accurately deter¬ mining the precise moment for starting the measurement of the alcohol content. In less than one second, and typically on the order of about

100 milliseconds, comparator 38 compares breath signature signal 26 with breath reference 32. If this produces a positive result, then breath signature signal 26 is found to be "valid" , thus sending a "yes" signal (shown with reference numeral 40) to the enable switch 180. This in turn enables second comparator 46 to commence performing the alcohol threshold "pass- fail" test .

Security hardware 92, previously described, operates as a second means for minimizing tampering with the apparatus 20 by the person in order to prevent the changing of any test result and to prevent damage to the apparatus. Alternatively or additionally, second means can be provided in the form of remotely locating each component of apparatus 20 at various locations in a vehicle, such as behind the dashboard or beneath the floor.

Mouthpiece 80 serves as a third means for providing a hygienic breath sample to sample 74.

The Fig. 5 separate component installation with the components joined by cabling provides a fourth means for easily installing apparatus 20 to interconnect into ignition system 86 of a vehicle 104. The com¬ ponents of apparatus 20 in combination (a) permit ignition system 86 to be started by the person if the person delivers a passing sample, and (b) does not permit the ignition system to be started by the person if the person delivers a failing sample.

The Fig. 6 installation featuring a handheld portable sampler, and the Fig. 1 arrangement of transducer 24, sensor 28 and controller electronics 128, provide a fifth means for performing the test quickly so no more than about ten seconds time elapses from the beginning to the end of the test. Preferably, however, no more than five seconds will elapse between the time a person delivers a test breath sample to sampler 74 and the time apparatus 20 delivers an ignition enable signal from ignition enable 84 to ignition 86 ; therefore, a person delivering a passing sample would be able to start an automobile within about five seconds after entering the automobile to start it.

Memory 52 operates as a sixth means for storing the test results to prevent access by the person who delivers the breath sample. However, memory 52 is designed in such a manner that a person authorized to retrieve the test results can do so (i. e. someone monitor¬ ing another person's breath sample history) . This would allow, for ex-

ample, for Caseload Management by a Probation Officer monitoring the breath sample entry of a person on parole from a drunk driving convic¬ tion.

Mouthpiece 80 is provided with springloaded latches 79 and 81, provided to positively hold mouthpiece 80 securely in place in sampler 74. Mouthpiece 80 is inexpensive and designed for being disposed after a single use; this ensures the delivery of hygienic breath samples. Integral trap 82 is provided with an arrangement of vanes for removing moisture and particulate matter entrained in the breath sample. The system of this Invention, in addition to the apparatus described above, offers a method for analyzing a breath sample 22. This method is comprised of the steps next described below.

Transducer 24 performs the step of sensing the temperature, the pressure and the humidity of the breath sample 22 and in response generating a breath signature signal 26.

Sensor 28 accomplishes the step of sensing the alcohol content if any of the breath sample, and in response generating an alcohol signal 30.

Breath reference 32 serves to do the step of providing a breath reference. Likewise, alcohol reference 36 performs the step of provid¬ ing an alcohol reference which includes an alcohol threshold level 36, which can be changed as desired using threshold level adjuster 37.

First comparator 38 accomplishes, the step of comparing the breath signature signal 26 with the breath reference 32 , and in response generating one of the following: (i) a valid signal 40 if the breath signature signal 26 substantially matches within a preselected range (passing envelopes 42A and 42B ) the breath reference signals (32A and 32B) ; or (ii) an invalid signal 44 if the breath signature sig¬ nal 26 does not substantially match the breath reference in the preselected range.

Finally, the second comparator 46 performs the step of compar¬ ing the alcohol signal 30 with the alcohol reference 34 and in response generating one of the following: (i) a passing signal 48 if the alcohol signal 30 is less than the threshold level 36 ; or (ii) a failing signal 50 if the alcohol signal 30 equals or exceeds the threshold level 36.

As can be seen in Fig 1 , a "yes" signal such as 40 and 48 , shown as a plus sign enclosed in a circle, indicates the desirable

condition; that is, signal 40 shows the breath signature signal 26 ha passed the validity test performed in comparator 38. Conversely, th undesirable condition is indicated by a "no" as with signals 44 and 48, shown as a minus sign enclosed in a circle; for example, signal 4 shows that the breath signature signal 26 did not pass the validity tes performed in comparator 38. The "no" signals 44 and 50 respectivel cause a system stop as at stop 45 and stop 51.

Threshold level 36 is shown in Fig. 1 to be set at 0.025% BA on a scale ranging from a low of 0.00% BAC to a high of 0.25% BAC This low-high range can be expanded; likewise it can be made sensitiv to thousandths of a percent BAC . Further, threshold level adjust 3 can be used to change threshold level 36 to be anywhere on the low high scale. The 0.025% BAC level is sufficiently below 0.10% BAC, th legal definition of being under the influence of alcohol, to protect th public and vehicle operators.

The expression "deep lung air" is synonymous with "alveola air" as defined in ϋ . S . Patent 4 , 316 ,380 to Heim, referenced above This is the portion of air delivered from deep in a person's lung; it i this air that is measured in order to determine a person's % BAC. Thi "deep lung air" is to be distinguished from the air delivered from person's oral cavity and pharylingeal cavity.

Memory 52 (Figs . 1 and 2) record test results including th mere fact that a breath sample was delivered to be analyzed and the to tal number of samples taken. The breath signature signal 26 produced by transducer 24 is i the form of a frequency spectrum.

The following U. S . Patent applications are hereby incorporate by reference into this present application, and form a part of thi application: Application of Brian P. Elfman and Lawrence R. Rojahn, seri number 06/494 ,301 , filed May 13 , 1983, entitled "Device to Preven Drunken Driving: , now abandoned;

Application of Brian P. Elfman, serial number 787, 266, filed Oc tober 15, 1985 , for "A System for Detecting Tampering", now pending; Application of Brian P. Elfman, serial number 791, 327, filed Oc tober 25 , 1985 , for "System for Breath Signature Characterization" , no

Application of Brian P. Elfman et al, serial number 813, 246, filed

December 24, 1985 , for a design entitled "Mouthpiece" , now pending; and

Application of Brian P. Elfman et al, serial number 813, 058, filed December 24 , 1985, for "Integrated Mouthpiece and Moisture Trap", now pending.

The examples discussed above in the Detailed Description il¬ lustrate only a few of the constructions and methods possible according to this Invention. However, it is understood that the following num- bered Claims both (1) define the Invention and (2) establish the scope of the Invention.