Sobriety interlock
First Claim
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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 thermocouple adjacent to and aligned with said port, said thermocouple being connected to said power supply and said ground terminal and having a junction and a temperature output line for electrical signals generated in response to the temperature of a breath sample flowing through said port, said thermocouple having means for heating the junction thereof to a temperature different from that of a breath sample received in 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 thermocouple 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 level.
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Abstract
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.
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Citations
27 Claims
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1. A sobriety interlock comprising:
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a power supply; a ground terminal; an "ignition on" input terminal; an "OK to drive" output terminal; means defining a breath receiving port; a thermocouple adjacent to and aligned with said port, said thermocouple being connected to said power supply and said ground terminal and having a junction and a temperature output line for electrical signals generated in response to the temperature of a breath sample flowing through said port, said thermocouple having means for heating the junction thereof to a temperature different from that of a breath sample received in 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 thermocouple 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 level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A sobriety testing apparatus comprising:
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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 including a thermocouple carried by the support, said thermocouple having a junction adjacent to and aligned with said port, said temperature 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, said thermocouple having means for heating the junction thereof to a temperature higher than that of a breath sample received in 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, 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 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. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification