CA1218734A

CA1218734A - Sobriety interlock

Info

Publication number: CA1218734A
Application number: CA000446576A
Authority: CA
Inventors: Jack Simon
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-02-01
Filing date: 1984-02-01
Publication date: 1987-03-03
Also published as: AU2398484A; JPS59184032A; SE8400511L; GB8402633D0; AU565207B2; GB2139387B; SE8400511D0; NL8400300A; DE3403450A1; SE456811B; FR2585082A1; GB2139387A

Abstract

SOBRIETY INTERLOCK Abstract of the Disclosure Apparatus for detecting alcohol on the breath including a microprocessor programmed to test breath temperature to guard against circumvention of the test. When the temperature test is passed, the breath alcohol concentration is measured. Responsive to the alcohol concentration, the microprocessor either: enables the ignition for a sober driver; enables the ignition for a tipsy but not drunk driver; disables the ignition, and imposes a programmed wait before allowing the test to be attempted again. BBBBB2/9629-1 JLM11-ooo

Description

12~8~39~
The present invention relates to alcohol testing devices and specifically to a device which uses the results of a sobriety breath test -to control a switch in an auto-mobile ignition system or in other machinery.
Description of the Prior ~r-t Automobile driving by intoxicated persons is a serious problem responsible for thousands of accidental deaths and extensive property damage every year, yet despite various preventive efforts the problem has defied 1~ solution. Many schemes have been sugges-ted to prevent drunks from driving, but because the schemes have all involved some driver inconvenience, none has gained wide-spread acceptance. Alcohol intoxication can be detected in various ways, all suffering from some drawback. A
practical preventive test must be executed automatically without supervision.
Reaction time and dexterity test results such as disclosed in U.S. Patents J,665,~4-/ and 3,610,943 respectively depend on individual abilities, are only indirectly related to degree of intoxication, and are not always meaningful. Alcohol intoxication is directly measured in a driver's breath by U.S. Patent 3,186,508 by measuring the optical property change of a chemical solution which is bleached by reacting with alcohol fumes.
This system requires an inconvenient frequent change of the solution. U.S. Patent 3,823,382 tests intoxication directly by an exothermic reaction of chemical granules with alcohol in a breath sample with a mercury thermostat to measure the amount of heat generated. The thermostat must be replaced after a failed test. U.S. Patent 4,093,945, tests intoxication by oxidizing any alcohol in a breath sample and measures the heat given off by a change in the electrical resistance of a sensor. That system is relatively complex and expensive.
In short, prior art drunk-driving prevention devices generally can be evaded, are inaccurate, unreliable, tedious, inconvenient, or complex and prohibitively expensive. For these and other reasons, no drunk-driving prevention system has gained widespread acceptance. There remains, therefore, a real need for a convenient, reliable, and inexpensive sobriety interlock system.
.i. :
. c ~ -- 1 -- ~ ~

kh/~`i j lZ~34 SUMM~RY OF Tl-IE INVE'ITION
_ . . .
It is the principal objec~ of this invention to provide an improved sobriety interlock which takes advantage of a microprocessor to achieve convenient, reliable, and economical control over operation of automobiles or other machinery by i~ebriated persons.
The microprocessor is programmed to make more flexible and advantageous use of breath sensors than ~las previously known. The interlock requires only a simple connection to an elec-trical starter sys-tem and derives its power from the starter system. No chemic~ls are used and rou-tine replacement of material is not required. The microprocessor first tests breath temperature, usi~g a thermocouple, to guard against circumvention of the test. When the -temperature test is passed, the breath alcohol concen-tration is measured based on the balance between adsorption and desorption of ethanol at the surface of a semiconductor sensor. The balance causes a measurable resistance change.
Specifically, the invention includes a source of electrical power and a breath receiving port; a temperature sensor adjacent and aligned with the port, the temperature sensor being connec-ed to a power supply and having a temperature output line for electrical signals generated in response to the temperature of a breath sample flowing through the port; a sas sensor ad]acent to and aligned with the port, the gas sensor being connected to the power supply and the ground terminal and having an alcohol level output line for electrical signals generated in response to the alcohol level of a breath sample flowing through the port; an analog-to-digital converter having a first input connected to the temperature sensor output line, a second input connected to the gas sensor output line, and a plurality of output lines for digital signals indicating the temperature and alcohol level of a breath sample flowing through the port; a microprocessor responsive to an input signal to read the digital signals on the converter output lines and to provide a signal as a function o whether the alcohol level in a breath sample is differe~t from a predetermined value, the computer having a plurality of gauge output lines for providing signals indicating computer operating states.
Responsive to the alcohol concentration, the - microprocessor either: activa-tes a steady green light kh k ~

lZ1~3734 and enables the ignition for a sober driver; activates a blinking yellow light and enables the ignition for a tipsy but not drunk driver; or activates a steady red light, disables the ignition, and imposes a programmed wait before allowing the test to be attempted again. The test may be repeated, after waiting each time until passed.

BRIEF DESCRIPTION OF TXE DRAWINGS
Fig. 1 is a block diagram of the sobriety interlock 10 used with a controlled system 100;

Fig. 2 is a preferred embodiment of the invention showing details of circuits that may be used for the blocks in Fig. l;

Figs. 3, 4, 5, 6, and 7 are examples of alter-native circuits that may be used for the blocks in Fig. l;

Fig. 8 is a side elevational view, partly broken away and in section, of the sobriety interlock, showing the mouthpiece attached to a housing containing the electronic circuitry of the invention; and Fig. 9 is a view similar to Fig. 8 but enlarged to show the placement of a thermocouple relative to a breath port or orifice.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention, a sobriety interlock 10, may be inserted as in Fig. 1 into a system controller, to test a human operator for sobriety and to prevent system use until the test has been passed. For example, the invention may be used in the ignition system 78 (Fig. 2) of an auto-mobile, or in other machinery that should not be operated by intoxicated persons. The sobriety interlock is installed in an automobile 100 by disconnecting line 98 between the key switch 97 and the solenoid in the starter system 99. The ends of disconnected line 98 are reconnected to the X

mab/i J~

~2~73~
input 89 and to the output 96 of an ignition enable circuit 90 controlled by microprocessor 80 (Figs. 1 and 2), preferably Intel Model No. 8048. The interlock uses five volt power line 5 supplied by power supply 40 which is connected directly to the 12 volt car battery, not shown, allowing the interlock to operate regardless of whether key switch 97 is closed.
In low temperatures, contaminants gradually adsorb into, and bias the characteristics of, sensor 14 (Fig. 2), which is preferably Model No. TGS 812 made by the Figaro Engineering Co. Continuous standby activation of heater coil 15 (Fig.

2) by heater driver 70 keepsalcohol sensor 14 free of contami-nation.

One begins the sobriety test by turning the key in ignition switch 97. Referring to Fig. 2, the current in line 89 passes through clipper 26 which clips spikes and smooths the voltage level to produce an "ignition on" signal on line 27. "Ignition on" signal 27 resets processor 80 and starts it on a routine such as the program in Appendix A, which works with an Intel 8048 as processor 80. First, a "heater on"
signal is applied through line 71 to driver circuit 70 for several minutes to heat coil 15 and sensor 14 from standby to ready condition. Computer 80 may activate heater driver 70 by a 12 volt supply from line 41 alternated with, or instead of, 5 volt line 5 in order to heat sensor 14 faster. During the heat-up period, computer 80 blinks the three LEDs 85 in rotation. Each LED preferably has its cathode connected through a 220 ohm resistor to a computer I/O pin, and its anode connected to the 5 volt supply. Even when free of previous contamination, the sensitivity of alcohol sensor 14 is affected by temperature.

Heater coil 15 maintains the sensor at a known constant temperature to minimize the effect of ambient air temperature. Heater 15 is turned off by a low voltage on driver 70, which pulls the base of mab/~

~L~21873~

transistor 74 low and prevents it Erom t~1rning on the transistor. A high voltage on driver 70 provides sufficient current through resis-tor 73 and the base and emitter of transistor 74 for the transistox to conduct 'i cu~rent to its grounded emitter from collector line 75, heater coil 15, and 5 volt supply 5 (or 12 volt supply 41). If alcohol sensor output line 16 were connected directly (not shown) to one of -the computer input pins, the computer could measure -the voltage drop across semiconductor sensor l4 to determine its resistance and thereby its tempera-ture, indicating whether the sensor is ready.
When the sensor is heated and ready for a test, green LED 81 lights steadily. The prospective driver then breathes into port l2. To guard against circumvention of the sobriety interlock, a breath temperature sensor 20, preferably a type J monolithic thermocouple amplifier model AD594 by the Analog Devices Co., is used to measure the air temperature in '0 breath port 12. Temperature sensor 20 varies the voltage on line 22 according to the (breath) tempera~
ture at point 2l in breath port l2. To determine whether the temperature in port 12 is within a ~5F
range around normal 98DF human breath temperature, the ~5 line 22 test voltage is compared by temperature compa-rators 60 against a temperature floor reference 37 and a ceiling reference 39. The temperature references may be supplied through adjustable SK ohm resistors 36 and 38 in a reference voltage supply circuit 30~
Floor reference voltage 37, representing 95F, is applied to the negative input terminal of comparator 67, and ceiling voltage 39, representing 105F, is applied to the positive input of comparator 69. The temperature test voltage 22 is applied through respective resistors 23 and 24, both preferably 12K
ohms, to the positive input of floor comparator 67, and to the negative input of comparator 69. Temperature ~aZ1~734 voltages 22 above ~he floor and below th~? ceilint3 cause both comparators 67 and h9 to act as sources of c~rrent flowing ou-l: through resisl,o.r 65~ pre~:e.labl.y 9.1K ohms, to supply vol.t.age li.ne 5~ T]l:is reslllts .in greater than i 5 volts on i'Temp O~" line 68, which acts as a "w.ired AND" gate providing inpul. tv pin C28 of computer 80, Althouyh the tempera-ture indication voltage on li.ne 22 will always satisfy at least one of the comparisons and that comparator w.ill ~aise ~he voltage Oll line 68, .if the line 22 voltage does no-t also satisfy the other comparison, that other comparator will act as a sink and pull the line 68 voltage bel.ow the s:ignal thres~lold of computer illpUt pin C29. When l'trem~ OK" line 68 has remained high for the programmed number of seconds r LED display 85 change.s from steady green to all three blinklng in unison while the alcohol level is tested for about 1.5 seconds.
Rather than using compaLators 50 and 60, voltaye reference supply 30, and their output lines, `~0 A-D converter 25 may be used to supply digitized values of temperature 22 and alcohol 16, Computer 80 is thus self--cal.ibrating and would then compare against values stored internally, The proportion of alcohol present in the breath is measured by gas sensor 13. Sensor 13 in-cludes a tin dioxide semiconductor 14 whose resistance is changed by absorption and desorption of ethanol according to the gaseous concentration at the sensor surface ~as well as the resistance being changed by temperature). The sensor output voltage on line 16 indicates the ethanol concentration. Current flowing to ground through resistors 17 and 19, preferably 1.5K
ohms and 6.8K ohms respectively, reduces the voltage from line 16 to a lower voltage in line 18.
. 35 Empirical tests have determined that the -' breath of a person having a blood alcohol level of 0.05% (tipsy, but not considered legally impaired) will lZ1~373~

cause the sensor l~l co procll~ce 3.1 volts on line 18 Testing a person hav;ng a O.lO% blood alcohol l.evel.
will producc 1..9 volts on line 18.. Re.Ference voltacJe supply c.ircuit 30 prov;des alcohol re:~exence vo:Lta(3es ; 33 and 35, equal to these level~, de.rived through variable resistors 32 and 34 by whic:h the .references may be calibrated. Comparator 55 compares the alcoho~
level voltage on line 18 agai.nst the 0.05% (lowe:r) standard on line 35, and produces a current in i-ts l~ output line 56 through resistor 57 according to the outcome of the compar:ison. An alcohol level less than low reference 35 causes comparator 55 to act as a current sink, reducing the voltage in Line 56 to Less than 5 volts. Conversely~ a test result voltage 18 L5 greater than low reference 35 causes comparator 55 to act as a cur.rent source raising the voltage :in line 56 above 5 volts.
Comparator 53 operates similarly ~o cause a currellt through preferably 9.2K ohm resistor 52 and .20 produce less than 5 volts in line 54 for alcohol test results less -than the high reference in :line 33, and more -than 5 volts in line 54 :For test results greater than reference line 33.
Microprocessor 80 uses the temperature verification signal 68 and the alcohol level comparison results 54 and 56 to decide whether the sobriety test has been passed. An al.cohol level below 0.05~ acti--vates the green LED continuously, and a high voltage "OK to Drive" signal output on line 88 preferably through a 1~ ohm resistor 47. A high signal on line 88 to the base of transistor 91, preferably a 2N4401, and preferably current from the 5 volt supply through a lOK
ohm resistor 48, cause the transistor to conduct current through its collector and a coil 92 in relay 93, preferably an AROMAT HBZE. Current flowing in coil 92 creates a magnetic field which attracts arms 94 ~2~l8~34 ~owards contacts 95, completing the circuit around disconnectecl line 98.
~ blood alcohoL leveL between 0 05~ and 0 1U~
provides a "tipsy" flashing yellow LED 82 which l-ne~ns that the vehicle should be drlven with cau-tion. ~ high "OK to Drive" signal enables relay 93~
If the blood alcohol level is above 0O10%, ~he brea~h -test is failed and interlock 10 will not allow the car 100 to be startedO "OK to Drive" line 88 L0 i5 held low, and red LED 83 blinks. The key switch 97 must be turned off and back on again to bring computer 80 to a 1'power up" condition and to re~start the test.
A four minute "long warm up" must be endured while heater 15 clears the sensor and hopefully the Xidneys clear the blood, of alcohol contamination.
A preferred embodiment of the structure defining the mouthpiece and the support for the elec-`
tronic circuitry of sobriety interlock 10 is shown in Figs. 8 and 9. This structure includes a housiny 110 ~o which is of a suitable material, such as rigid plastic r and which is rugged in construction. The housing is provided to contain and to protect the circuit boards and other electronic components contained therewithin against damage, such as in the event that the housing is dropped on a surace. One of the circuit boards 112 is shown in Fig. 8 within housing 11~ A cable 114 having leads 116 extending outwardly therefrom connects the electronic circuitry with an external power source, such as the battery of a vehicle, and also connects the circuitry with the ignition system of the vehicle.
Housing 110 has a tubular neck 118 to which a tubular extension 120 is secured. Member 120 is rigid and can be formed from any suitable material, such as aluminum. For purposes of illustration, extension 120 includes a metallic member 121; such as of aluminum and a rigid plastic member 123 secured to and extending outwardly from one end of member 121. The outer ~L2~8734 su.rface of mernber 1~1 has annular ribs 122 thereon tv help ;n dissipating heat absorbed in the member, Sensor l4 is rnounterl in any su.itab].e rnanlle:r~
such as by a press fit wit.hin member 121. near the oul:er open end thereo, Gas se~so.r 14 is adjacent ~o a .number of spaced openings 124 through member 1.21 so that -the space 126 adjacent to the out~r ~ace of gas sensor l4 communicates with tlle atmosphere to assist in cleaning -the sensor as hereinafter described.
.n Member 123 conta;ns a -tubular, heat insulat-ing element 130 typically of cork for shieldi.ng a portion of the breath temperature sensor 20 which i.s coupled by leads 132 to the circuitry in housing 110, leads 132 extending through member 120 as do a pair of leads ~not shown) coupled with gas sensor 14. Such leads are connected to the circuitry contained in housing 110~ Ternperature sensor 20 includes a thermo-couple 134 shown in more detail in Fig. 9.
A mou-thpiece member 136 is secured to the ~o outer end of member 123 and has an outer end 138 over which the mouth is placed for blowing a breath sampl~
into mouthpiece member 136, An internal bore 140 ;.II
mouthpiece 136 contains a tubular element 142 havins a fluid flow passage 144 therethrough, whereby the breath sample under pressure in bore 140 can enter the space 146 containing thermocouple 134.
Thermocouple 134 is shown in its preferred location in Fig. 9 at the downstream end of passage 144. It can be seen from Fig. 9 that the thermocouple junction 135 is physically at the end of passage 144.
The reason for this is that the thermocouple will be immediately sensitive to the temperature of the breath before the breath expands into space 146 and is thereby cooled.
Thermocouple 134 has a heating element 148 in heat exchange relationship thereto at a location spaced a short distance, such as .25 to .50 inch, from 121~734 junction 135 as shown in Fig. 9 HeateL 148 comprises d heating coil within a vacuum envelope 150 surrounding ~ portion of thermocouple l34. The purpose o~ heating coil 1~8 is to eliminate the tendency for sobriety ~; interlock 10 to automatically turn itsel~ on if the ambient temperature was about 98F. To eliminate this problem, the heater 148 is placed ;n heat exchange relationship to the thermocouple, specifically to both wires thereof, to heat the thermocouple to a tempera-ture above the 98~ normal breath -temperature. For example, it can be heated to 130~F and this is con trolled by microprocessor 80 so tha-t the temperature of the heated portion of the thermocouple remains at about 130F. A small transistor can be switched on and off lS to regulate and stay at this temperature level, this heating being done by conduction to the junction 135 of the thermocouple. Thus, when a person blows into mouthpiece member 136 with the breath temperature at about 98F, the thermocouple cools down from the 130F
temperature so that sobriety interlock 10 can then commence a valid test.
Another important feature of the structure shown in Figs. 8 and 9 is the use of passage 144 which typically has a diameter of .075" to .130"; Thus~
~S passage 144, which provides, in effect, a small orifice, forces a person to blow into the mouthpiece such that a slight air pressure is developed in t~he mouthpiece member This forces the lips of the person to maintain an air seal about the mouthpiece member so as to prevent outside air from entering the brea-th sample directed into and -through passage 144. Outside air would otherwise alter the results of the operation of sobriety interlock 10.
Passage 144, because it has a finite length, directs the breath flow onto the thermocouple junction 135 and then through extension 120 and onto gas sensor 14. To do this, a temperature of 95F must be sensed . . . ~

1;~18734 1 l hy the the~mocoupl.e for a pe~iod of a-t l~ast four seconds so that a deep lung breath sample is measured.
~ince opellings 124 (Fig. 8) ar.e provided i.n ~ember l.~l, the gas sensor will be in Eree ai.r which is essenti.a.l for cleanup of the sensor. With the use o~ openings 12~, it is possible to conduct a first test and have the senso:~ cleaned up in order to make a next test i less than .l5 seconds~
Ano-ther feature of the present inverltion with respect to the cleanup of gas sensor 14 involves the use of a fre~uency (about 10 to 100 Hz) controlled voltage source applied to the sensor during the cleanup period. This frequency controlled voltage source is used instead of a steady voltage source to heat the sensor. Ordinarily, with a steady voltage, the cleanup period is about ten seconds as recommended by the manufacturer of the yas sensor. By using a frequency controlled, variable vo:Ltage source ~enerated by microprocessor 80 to heat the sensor, this cleanup time is cut to less than five seconds. It is also possible to improve the accuracy o:E the gas sensor results~
This is done by using the microprocessor R0 -to check the level at which gas sensor 14 is cleaned up to, at -the time a test is started. This starting point has a significant bearing on the results of an alcohol breath test. In the analog to digital version of sobrietv interlock 10, compensation for any variation to starting point can be adjusted automatically by the mic.roprocessor 80.
Details have been disclosed to illustrate the invention in a preferred embodiment of which adaptions and modifications within the spirit and scope of the invention will occur to those skilled in the art. The scope of the invention is limited only by the following - claims.
The program can also contain in software an option such that, if a vehicle is not operated for 48 ~Z18734 .l:la hours or othe.r time pe.r:iod~ t.he autorrlatic c.leaning cycle for the gas sensor i.s overridden t:o preverlt the drain on the battery of the vehi.cle which supplies powe.r t~ the circu:itry. Thus, the circuit shuts ltself off. The only disadvantage of this is that clean:i.ny o~
the gas sensor may take a minute when the vehicl.e is next operated rather than 10 seconds for nor~al operation~
A con-trol program for: use with interlock :LO
is shown on the follow;n~ pag~s.

." . _.___ _ , ..................... _ , . ......... . . . . .
~....... ' '' .

:~Z~8734 REGISI`ER USAtE
REGISTER ~ANK ZERO

3 ~ 1 0 } _ _ . _ _ _ _ _ _ _ _ . .. . _ .. ,, .. , _, _ _ . , .. ~
I COUNTER USED BY LON~ARI~IUP AI~V GRACE~AlT
..... . . . , .-- .

, -- , _ ~,, -- , , _ _ _ _ _ _ _ , , _,, -- , _ _ _ _ _ _ _ _ _, _ _ _ _, _ , _ _ , ,, _ +
~ UTILITY COUNTER USED BY PURGE ETC
_, ,, _ _ _ _ _ _-- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ,_, _, _ _ _ ~
I - COU~TER FOR ~AIT 1 SEC BUT A~ORT IGN ON/OFF ~OUTINES
~ . . .. ., . ., . _ _ _ _ ._ _ ._ _ , ._ _ _ _ _ _ _ ,_ ,_ . _ _ _ _ _ _ _ .. _ _, .. _. _ _, . .. , ... . ._ _ _ ~
~ USED TO SAVE A DURING CLOCK INTERRUPT
~. _ ... , .. . , . . _ _ _ _ _ _ _ , _ _ _, _ _ _ _ _ _ _ _ _ .. , _ ... _ . _ , ...... , .. .. _ _ ~
OUTPUT VALUE TO SEND TO Pl ~ _ _ , _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ , _ , _ _ _ , _ _ _ _ +
~ OUTPUT VALUE TO SEND TO P2 ~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ,_ _ _ _ _ _ , _ _ _ _ _ _ +
ipr~ ALC>~51 ¦ ¦ALC10 lALC05 ¦TE;-lPOK ¦IGN ON ¦
! BREAT~ TEST RESULTS ¦ INPUT STATUS
.~ ,, . _ . . _ . . . ,_ _ _ _ ._ _ ,_ _ _ _ _ _ _ _ _ _ . _ ._ _ _ _ _ _ _ _ . ., ,_ _ _ .. _ _ _ _ _ , . _ _ . _ _ _ ,, ~ .. _ ., . _ ,_ ,_ +

R ~ISTER BANK ON
6 5 4 3 ~ 1 0 * _ _ _ . , ._ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ ,_ _ _ _ _ _ _ _ ,_ _ _ ,_ _ _ _ _ _ ._, . _ _ ._ _ _ _ ~
I RE~ ¦YELLOW ¦ GREEN ¦ RED ¦YELLOW ¦ GREEN ¦ CYCLE ¦ BLINK ¦
¦ BASIC LED PATTERN ¦ CURRENT EED PAT~ERN J LED ACTIVIT~ l ~______ _____________________ _________________________ ________~
I DO-~.N COUNTE~ USED BY TICK TO CONTROL LED TIMING
_ _ , _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ +

_ _. ~ _ _ _ _ _ _ _ _ _ ._ _ _ _ _ . _ _ _ _ _ . ., .. _,, _ _ _ _ ._ ._ ._ _~ _ . _ _ _ _ _ _ _ , _ _ _ _ _ _ _, _ _ _ _ +

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ , _ _ _ _ _ _ _ _ , _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ +

~__ _______ -- ---_ ____________________ ____,_________ ______~
I COUI~TER USED BY WAIT .01 SEC"
* _ ~ -- +
I CCUNTER USED BY .~AIT .Ol SEC
+_________ ___ _ ____ ___________________________________+
I COUNTER USED BY `:AIT 1 SEC~ l _ _, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _-- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ , i~ 3~ .. 1218734 . . . . . .. . . .. . . ......... . . .. . .. .. ... . .. .. . .. . .. .. .. ..
I E5 pOWE~ON SEL l-lB0 PO~ER ON COI~ES H~RE
~1l J~P POWERUP
2 g 3 ~3 RETR DUt~l~Y 1N'r~R~1JP'r SER~tR

i S4 J1~P 'rlCK CL.OCK TICK SERV~R
~0 0 Eli PO~ERUP- SEL ~B0 l C~ SEL RB0 2 B~ MOV R5~0F

4 BE 1~0V R6,~00 '5 a~ I
'6 3F MOV R7~r00 7 `3~
~8 23 1~0V A~7D
>9 7D
7A 62 1-10V T~A
~B 55 STRT T
2C 25 EN TCNTr 2D 00 NOY_ -2E` 0e NOP

54 i,ONG~AR~1'JP~ CALL SETL.CYCI,E START LEDS CYCLING
31 ~0 33 54 CALL ~EATON TURN ON HEATER
3~
3~ IIOV R0, ~F0 START 4 I~INU'rE T~MEOUT
;35 F0 ;36 74 L~;Ul: _ CALL WAlTlSEC WAlT 1 SECOND
~3~
~3~ E8 DJNZ R0~LWUl LOOP TILL 4 MINUTES UP-~3C, 3~ 1 ~3~ ~3~ NOP
33~ a0 NOP
3 3 ~ 3 N O P
~)3~ ~0 NOP
a3~ ~0 NO~
~3~; ~0 NOP
040 54 IGNOFF: CALL SETLCYCLE START LEDS CYCLING
041 D~ I o 042 BD l'lOV R5, ~ EF

D44 BE ~IOV R6~00 D4S 130 . I

047 4a . I
04El 00 NOP
04g .00 NOP
~4A FF MOV A~R7 ~4P . 12 . JB0 IGI~ON
~4C ' 60 D4D 04- ' J~'~P IGNOFF

~ o P

14 .(GNON: CAL,L SHOR'I'\~RI~UP

S~ ` CALL. BL,INKGRN
0~1 1 NOP
~0 NOP.
3~ CALI. '~s~l~BR~A
; ~0 NOP
J ~ NOP .
~ ~ MOV A,R7 3 F2 JB7 ~RUNK
' D2 J~6 TIPSY
-~' 78 00 ~OP
a 00 SOBER: NOP
~ 54 CALL S'rEADYGRN

4 ~0 NOP
~0 NOP
6 04 Jl~P ~RIVE
'7 80 18 00 TIPSY: NOP
1~ U0 NOP
7A 54 CALL. 8LI~KYEL

7D 0~ NOP
7E 00 ~ NOP
54 DRIVE: CALL HEATOF~
882 F8E ~OY A,R6 ;83 43 ORL A,~10 '8~ AE 110V R6,A
,8G 00 WAlTIGNOFF: NOP
18-~ 00 NOP
~8~ FE` JB0 WAITIGNOFF
,88A 8064 J~1P GRhCE
08~ B0 0A1 00 DRUNK: NOP
aA2 ~ 54 CALL BLINKRED
ZA4 FF DRUNKl: JB~ DRUNKl 0A6 A4 1 / y ~Z~8734 BA l'lOV R2, " 0 F.A DJI`~0 R2 t ~' A~
0`'1 J~P 1,ONG`~JARi`1lJP
3~ 1 .

F ~i~ACE. I`~IOV A,R~i DISA131,E STAR'~'ER
58 ANL A, ~ EF
AE J~OV R6,P.
I 54 . CALL HEATON
3 B13 ~lOV R0,nF0 4-~1INU'l`E GRACE PERIOD
3 74 GRACE~AIT: CAL.L ~JlSBAlON ~ ( W~
3~ 1 12 JB0 DRIVE IF lGN ON, GO S'rAR'r CAR
D E 8 DJNZ R 0 ~ G RA C E1~1 A I T
. E B%

:0 10 ~0 5~ SHORT'~'ARMUP: CALL HEATON
D~ 10 D.f B8 MOV R0, ~ 20 D3 .~0 04 FF SWULOOP I~OV A, R7 D' 37 CPL A
D~ JB0 Sl~lUEXI'r ~D- DC~ ¦
`D~ 74 - CALL ~lSE3AIO
3D~ 2~ 1 )Dl~ E8 DJN2 R0, S`.~ULOOP
JDI' D~43 SI~UEXIT~ RET

l00 Ç30 TESTBRrATH: NOP
l0 1 00 NOP
l02 00 NOP

10-~ FF MOV A,R7 105 53 ANL A, ~ E3F
107 AF I~OV R7 ~ A

1 0 9 0 0 h'A I TS TAB LE: M OV R 2, '' 3 2 1 D t~ ws LOO P: ~i ov A, F~7 J~S--.~ I
,. J~ XII' JB1 WAlTSTABI,F: .
~ I , J' 7~ CAI.L. WAI'r01 1~?
XA D~NZ R2 ~.St.OO~ .
.
~ NOP .
B~ ~IOV R~ 9~ S'rAR'I' AL.COHOI, TEST .
9~ I .
~F AL{N~OOP ~OV A,R7 , 12 JB0 TBEXIT .

32 J81 WAlTSTABLE

NOP

53 ANL A,~0C

97 SI~AP A
~F ORL A,R7 AF MOV R7, A
NOP
0~ I~OP
74 CALL ~AIT01 EA DJN~ R2jALCLOOP
lA
0~ NOP

~0 NOP
34 'I'BRET: CALL BLINKALI.

74 CALL WlSBA:[O
7~1 CALL W15BA~O
2~ 1 00 ~OP
OP

D5 B],~NKALL: SEL RB1 ~8 - I~OV R0,~D
E~I) I -D5 SETLCYCLE: SEL RBl BB ~OV R0,-~26 B9 ~OV Rl,~01 ~1 I /~ "' ' 12~8~734 C~ , ".,1.. ~.

~5 13LINKGRN~ SEL RBl BB l'lOV R0/~5 FU '.-~EATON: I~OV A,R5 43 ORI. A,N10 I
MOV R5,~
~-3 RET

E`~ HEATOFF: MOV A,R5 ~ $3 ANL A,~EF
3 AD . ~IOV R5,A
_ ~3 RÉT

0 ~5 LEDSOFF: SEL RBl 1 B8 MOV RQ,~0 .4 83 RET

~ ~5 STADYGRN~ SEL RBl ~ MOV R0,~4 2(~24 SEL RB0 3~ DS BLINKYEL. SEL RBl 31 B8 MOV R~,~43 38 D5 BLINKRED: SEL RBl 39 B8 lviOV R0,~9 333~C 83 SEL RB0 .
40 0~ PURGE: NOP

44 B8 ~OV R0,~05 CYCLE 5 SECONDS ON
4~ 5 / ~

. .

~L873~
1 2 J B0 L'UI~ .X.I i ~ I
74 CAI.L WlSBAlO~

E8 DJNZ R0,PONLOOP
'~6 ~3~ CALL HEA'I'OF`F
OV P~0, ~j ~0 E~ P~!PELOOP~ MOV AIR7 ~ JB0 PURGEXlT

7~ CALL WlSBAIO~I
3~ 1 ~ - DJNZ R~,PO~ELOOP

~3 Pl;RGEX:I'r~ RET

O5 WAXTlSEC: SEL RB1 MOV R7,~64 74 ~`i]SECI,OOP: CALL WAI~01SEC
D5 SEL RBl EF DJNZ R7,WlSECLOOP
~4 7 D5 ;~AITDlSEC: SEL RBl BE MOV R6,~08 0~ 1 BD W01SECLOOP: ~OV R5)~FA
E~ DJN~ R5,*
lS
EE. DJN~ R6,W01SECLOOP
1'~ 1 ~ 83 RET

3 00 WlSBAIO: NOP

2 BB I~OV R3,~6 3 6~ 1 4 7~ WlSBAIOLP: CALL WAIT~lSEC
6 FF MOV A,R7 8 12 JB~ WlSBAIORET

i23L8734 ~; ~, D,~ Z ~ L ~ J
B3 WlSBAIORET: RET

00 Wl:`BAION: NOP
B0 MOV R3, ~ f 4 74 Wl'iBAlOI\lLP: CALL WAI'r0:1SEC
FF tlOV A, Rl 12 J B 0 W l SB A I ON R ET

EB riJNZ R3,~15BAIONLP

83 ~'lSBAIONRET- KErr C5 TICK: SEL RB0 C I~OV Rq, A
F F MOV A,R7 53 ANL A,l,F0 AF - MOV R7,.
09 IN A, Pl 9 4F ORL A,R7 AF ~OV R7, A
B 23 MOV A, D`7D
E6 2 1~1 OV 'r, A
E`39 OUT Pl ,A
~l~E OUT P2,A
.2~0 l\lOP

:6~ig I~OP

~5 Dl)LE:DS: SEL RBI
E9 DJNZ Rl, DONELEDS

1 J~i~ L~ L 1 1. 1~ ~Z18734 32 J~1 CYCLE
53 Sl`EADY: ANL A,~E3 ~9 t~OV Rl,A

RR A
-53 ANL A,#lC
. 1~
~ 6~ J~P SETLED
L
~ A9 ~LINK: MOV R1,A
?. 7-7 RR A

-~7 RR A
~ 53 hNL A,~lC
7 lC
3 D9 XRL A~R1 9 53 A~ nlC
A lC
a 54 J~P SETLED

0 A9 CYCLE: MOV R1,A
1 E7 ~ RL A
2 53 A~L A,~18 3 1~5 14 96 J~ SETLED
~5 90 ;6 23 MOV A ~04 57 0~ - I
~8 64 . J~P SETLED
3g 90 A8 SETL.ED: ~OV R0/A
31 F9 I~OV A,R1 3~ 53 ANL A,~E3 94 48 ORL A~R0 96 B9 MOV R1,~0A
97 ~A
98 C5 DONELEDS: SEL RB0 99 FD i~OV A~R5 9A 43 ORL A~E0 .9B E0 i9C AD MOV R5,A
59D F~ I~OV A~R7 ;9F E6 JNC DONETICK
5Al O0 NOP

~A~ 00 NOP

~ D5 F~ I~OV A ~ ~0 lZl !3734 53 ANL A~ $ lC
lC
E~ Rl.o P~
~7 RL A

~D XRL A, RS
Al~ I~OV R5, A
0~ NOP
~ I`lOP
FC DOI`lETlC~ lOV A jR~

t ~ t Y. ~ * * * * * * EN D O F PR OG R AI`I * * ~ .~ * ~ * ~ l * * A ~ * ~ * :'' * h * *

~2/
;''` ' :~Z~87:~4 ' ,~, r SOLlF::RLIZER PROGRAM FLOW CHART
* ~ ,; .': * J~ t; ff * * * ~ * * * * * * ~ * * * * * * * * * * * ~ k * * * ~ A * -* ~ * * * ~ * * * * * * * * * ~ * * -,~ * r.

+ ~ , . :
PO~ER ON I
*.___ _ _ _ ___ __ __~ ..
~ _ _ _ _ _ _ _ _ _ _ _ ~ ~:
¦ START CLOCK ¦ ..
¦ 10 MS~ TICK ¦
:.
., t -- -- ~ :
¦SET L.E.D.. CYCLING ¦ .
~_ __ _ _ ___ _ __ _ _ .____ _ ~.~
~_______ ______ ~ .
¦TURN ON HEATERS¦
_____._____ _____~

._ ._ _ _-- .---------- ---- . ------------ -- -- -- -t j'~AIT 2 MINUTES TO HEAT UPi .
t ---------- -- ------ .--- -- -- .-- _ _ _ . . _ . ._ ~ ~
.~
.~ _________ __________ _ __ . _ _~ .
t'l`:~ t'N OF~ WAIT TILL IGI~IITION ON I .
CYCLE HEATER OE`F & ON ¦ .
} _ _ ._ _ _ _ ._ .

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ tTION O~ SET GREEN L. E.D. FLASHING¦ ., ~.______._ ________________ .. ~ ..
.~
~________._________________~
¦l.YAIT FOR TEI~P. OK & STABLE¦ .

~_________________.___ ___.._~.

~_______ _ ___ __ _ __. _ _,. ______. . _ ,~, TEST ALCOHOL FOR 1 SECo I .
I IF TEMPTo NOT OK~ GO aAcK TO ¦ .
¦ PREVIOUS STEP S ET ALL L . E ~ D . ¦ :
¦ FLASHINC FOR 1 SECOND ; . .
, . ~__ ______________ ___________._,~ .
t -- -------------------------i ~ - - - ALCOHOL LEVEL?---- I
~_________--____--__________----------+ X

.. ~.. , . , . U~ ." . 1 V
<.10 T(, Sl~3ER 1'0 TI PSY 1'0 ORUI`l~
'~
O~IER~ TIPSY:
.. _ . .. ~ . .. _ _ .. _ . .~ _ ._ _ _ ._ .,. . _ _ _ ~ ,~ _ _ _ . _ _ _ ._ _ _ _ _ _ _ . _. ~
TURN ~IEM L.E.D. ON STEADILYII START FLASHING YELLOW LED I
~ t _ _ ~ +
I ENABLE STARTER
_ _ _ _ _ _ _ _ _ -- ~
I

~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~
I WAIT FOR IGNITION TO GO OEE I -t . __ _____ _ ~

~___-____ ________ ____ ________~
¦WAIT 1 MINUTE, IF IGNITION TURNS I
IBACK ON, GO BACK TO PREVIOUS STEP¦
.~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .. _ _ . .. . _ _ _ _ _ .~
.~ _ _ .. _ _ _ ._ _ _ _ t I TO IGNITION OFF
_ _ _ _ _ _ _ _ _ _ _ _ _ _ ~ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ . . . _ . . +
I?RiJ~K- ------->I STEADY RED L.E.D, I
~_____________ _______+
I

f _ __________ _ I ~AIT EOR IGNITION OFF I
~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~ *

CLOCK (ONCE EVERY .01 SECOND
*******~*************************
+_______________._________ _____~
¦TEST ALL INPUTS & RECORD VALUES¦
+____________________________.__.~
t -- --_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ +
IHAS E~OUGH TIME ELASPED TO CHANGE L.E.D.?¦-^---NO----+
__________________.________ __ _ ___ ___ ~, I
YES l *____________ _ __ __ +
¦CHANGE L~E.D.STATE AS APPROPRIATE¦
+ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _-- t ^
~___________________+
IS IGNITION ON ? ¦ <----------------------------------~ .
+___________________+
YES / \ NO
+___. _________________+ ~_______________________+
I ENABLE L.E.D.S I ¦ DISABLE L.E.D.S
t ~ +
/
+_______________________+
I EXIT I ~ ~
~ + cSC .a **A******~*********~***********~***********A*****~******~********~*~

Claims

CLAIMS:

1. A sobriety interlock comprising:
a power supply;
a ground terminal;
an "ignition on" input terminal;
an "OK to drive" output terminal;
means defining a breath receiving port;
a temperature sensor adjacent and aligned with said port, said temperature sensor being connected to said power supply and said ground terminal and having a temperature output line for electrical signals generated in response to the temperature of a breath sample flowing through said port;
a gas sensor adjacent to and aligned with said port, said gas sensor being connected to said power supply and said ground terminal and having an alcohol level output line for electrical signals generated in response to the alcohol level of a breath sample flowing through said port;
an analog-to-digital converter having a first input connected to the temperature sensor output line, a second input connected to the gas sensor output line, and a plurality of output lines for digital signals indicating the temperature and alcohol level of a breath sample flowing through the port;
a microcomputer responsive to a signal at the "ignition on" terminal to read the digital signals on the converter output lines and to provide a signal at said "OK to Drive" terminal as a function of whether the alcohol level in a breath sample is different from a predetermined value, the computer having a plurality of gauge output lines for providing signals indicating computer operating states.

2. An interlock as in claim 1 further comprising:

a clipper circuit connected to said "ignition on" terminal;
an "ignition enable" circuit connected to said "OK to Drive" line;
and wherein said clipper circuit is adapted to be connected to the key switch in a motorized vehicle, and said "ignition enable" circuit is adapted to be connected between the key switch and the starter solenoid in the vehicle.

3. An interlock as in claim 1 further comprising a heater drive circuit connected between said power supply and said gas sensor, said driver circuit being responsive to a signal from said computer to provide a current to said gas sensor, and wherein said gas sensor has a heating element powered by the heater drive.

4. An interlock as in claim 1 further comprising:
a separate indicator connected to each of the plurality of gauge output lines of the computer.

5. An interlock as in claim 1 wherein said analog to digital converter comprises:
a voltage reference circuit connected between said power supply and said ground terminal and having separate output lines on which said reference circuit provides electrical signals indicative of each of:
an alcohol high reference;
an alcohol low reference;
a breath temperature high reference;
a breath temperature low reference;
an alcohol comparator circuit connected to the alcohol sensor output line and having a first comparator connected to compare the alcohol sensor output to the alcohol high reference;

a first alcohol output line to which the first comparator applies a signal indicative of the high comparison result, a second comparator connected to compare the alcohol sensor output to the alcohol low reference; and a second alcohol output line to which the second comparator applies a signal indicative of the low comparison result;
a temperature comparator circuit connected to the temperature sensor output line and having a third comparator connected to compare the temperature sensor output to the temperature high reference;
a fourth comparator connected to compare the temperature sensor output to the temperature low reference; and a temperature output line to which said temperature comparator applies a signal indicative of the temperature comparison results.

6. A sobriety interlock as set forth in claim 1, wherein said port defining means comprises a mouthpiece member having a fluid passage therein for receiving a breath sample, said temperature sensor being near the downstream end of said fluid passage.

7. A sobriety interlock as set forth in claim 6, wherein the temperature sensor includes a thermocouple having a junction near the downstream end of said fluid passage.

8. A sobriety interlock as set forth in claim 7, wherein the junction of the thermocouple is in the fluid passage at said downstream end thereof.

9. A sobriety interlock as set forth in claim 8, wherein the thermocouple has means spaced from the junction for heating the same so that the junction will be at a temperature different from the temperature of a normal breath sample passing through said filled passage.

10. A sobriety interlock as set forth in claim 9, wherein said heating means includes a sealed envelope surrounding a portion of the thermocouple, and an electrically actuated heating device within the envelope in heat exchange relationship to the thermo-couple.

11. A sobriety interlock as set forth in claim 9, wherein is included a heat insulating tubular member in surrounding relationship to said heating means.

12, A sobriety interlock as set forth in claim 6, wherein is included a tubular extension secured to the mouthpiece and extending outwardly therefrom, said temperature sensor extending through at least a portion of said extension, said gas sensor being in said extension downstream of the temperature sensor with reference to the direction of flow of a breath sample passing through the extension.

13. A sobriety interlock as set forth in claim 6, wherein is included a housing coupled to the outer end of the extension, said housing containing said converter and said microcomputer, said housing being of a size and weight to permit it to be hand-held as a person blows into the mouthpiece member to deliver a breath sample thereto.

14. A sobriety testing apparatus comprising:
a support;

an elongated, tubular mouthpiece mounted on the support and extending outwardly therefrom, said mouthpiece having a breath-receiving port;
means defining a source of electrical power;
a temperature sensor carried by the support adjacent to and aligned with said port, said tempera-ture sensor being coupled with said power source and having a temperature output line for electrical signals generated thereby as a function of the temperature of a breath sample passing through said port;
a gas sensor carried by the support adjacent to and aligned with said port, said gas sensor being coupled with said power source and having an alcohol level output line for electrical signals generated thereby as a function of the alcohol level of a breath sample passing through said port;
an analog-to-digital converter having a first input connected to the temperature sensor output line, second input connected to the gas sensor output line, and a plurality of output lines for digital signals indicating the temperature and alcohol level of a breath sample passing through the port; and a microcomputer responsive to an input signal for reading the digital signals on the converter output lines and to provide an output signal indicative of whether the alcohol level in the breath sample passing through said portion is different from a predetermined level, the computer having a plurality of gauge output lines for providing signals indicating computer operat-ing states.

15. An interlock as in claim 14, further comprising:
a clipper circuit, an enable circuit, said clipper circuit adapted to be connected to a switch, and said enable circuit is adapted to be connected between the switch and another operable electrical component.

16. Apparatus as in claim 14, further comprising a heater drive circuit connected between said power source and said gas sensor, said driver circuit being responsive to a signal from said computer to provide a current to said gas sensor, and wherein said gas sensor has a heating element powered by the heater drive.

17. Apparatus as in claim 14, further comprising:
a separate indicator connected to each of the plurality of gauge output lines of the computer.

18. Apparatus as in claim 14, wherein said analog to digital converter comprises:
a voltage reference circuit connected to said power source and having separate output lines on which said reference circuit provides electrical signals indicative of each of:
an alcohol high reference;
an alcohol low reference;
a breath temperature high reference;
a breath temperature low reference;
an alcohol comparator circuit connected to the alcohol sensor output line and having a first comparator connected to compare the alcohol sensor output to the alcohol high reference;
a first alcohol output line to which the first comparator applies a signal indicative of the high comparison result;
a second comparator connected to compare the alcohol sensor output to the alcohol low reference; and a second alcohol output line to which the second comparator applies a signal indicative of the low comparison result;

a temperature comparator circuit connected to the temperature sensor output, line and having a third comparator connected to compare the temperature sensor output to the temperature high reference;
a fourth comparator connected to compare the temperature sensor output to the temperature low reference, and a temperature output line to which said temperature comparator applies a signal indicative of the temperature comparison results.

19. Apparatus as set forth in claim 14, wherein said mouthpiece has a fluid passage therein for receiving a breath sample, said temperature sensor being near the downstream end of said fluid passage.

20. Apparatus as set forth in claim 19, wherein the temperature sensor includes a thermocouple having a junction near the downstream end of said fluid passage.

21. Apparatus as set forth in claim 20, wherein the junction of the thermocouple is in the fluid passage at said downstream end thereof.

22. Apparatus as set forth in claim 21, wherein the thermocouple has means spaced from the junction for heating the same so that the junction will be at a temperature different from the temperature of a normal breath sample passing through said fluid passage.

23. Apparatus as set forth in claim 22, wherein said heating means includes a sealed envelope surrounding a portion of the thermocouple, and an electrically actuated heating device within the envelope in heat exchange relationship to the thermocouple.

24. Apparatus as set forth in claim 22, wherein is included a heat insulating tubular member in surrounding relationship to said heating means.

25. Apparatus as set forth in claim 19 wherein said support includes a tubular extension secured to the mouthpiece and extending outwardly therefrom, said temperature sensor extending at least a portion of said extension, said gas sensor being in said extension downstream of the temperature sensor with reference to the direction of flow of a breath sample passing through the extension.

26. A sobriety interlock as set forth in claim 19, wherein said support includes a housing coupled to the outer end of the extension, said housing containing said converter and said microcomputer, said housing being of a size and weight to permit it to be hand-held as a person blows into the mouthpiece member to deliver a breath sample thereto.