Optical Breath Alcohol Sensor with Dual-Port Air Input
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Solution Overview
Problem
Current chemical vapor sensors for detecting ethanol in breath have limited lifetimes, are impractical for on-board vehicle use, and require undiluted breath samples, making them unsuitable for long-term, practical drunk driving prevention systems.
Innovation Solution
A chemical vapor sensor system with an air input device, light source, detector, and processor that alternates air samples between a sample input and reference input, using infrared light and dual-element IR detection to measure carbon dioxide and ethanol levels in exhaled breath, allowing for non-contact BAC determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrochemical sensors are used to measure ethanol concentration, then ethanol detection capability is achieved, but sensor lifetime is limited to about three years
Solution Approach 1:
The patent replaces electrochemical sensors with an optical detection system using infrared light sources and detectors. This substitution eliminates the chemical degradation issues inherent in electrochemical sensors, achieving a sensor lifetime of at least ten to fifteen years while maintaining ethanol detection capability through measurement of infrared light absorption by ethanol molecules in breath samples.
2Measurement precision
If metal oxide film sensors are used, then ethanol detection sensitivity is improved, but the sensor requires undiluted breath samples which limits practical application
Solution Approach 1:
The patent changes the detection parameter from direct ethanol concentration measurement in undiluted breath to infrared light absorption measurement. This allows the use of diluted breath samples mixed with ambient air, as the infrared absorption spectrum of ethanol remains detectable. The system measures ethanol by detecting its characteristic infrared absorption at specific wavelengths, enabling practical on-board vehicle use without requiring pure breath samples.
3Measurement precision
If infrared light transmission through driver's extremities is used, then BAC measurement is possible, but the approach is impractical for on-board vehicle use
Solution Approach 1:
The patent extracts the ethanol detection function from complex medical imaging systems and creates a dedicated, simplified breath analysis device. Instead of using infrared transmission through body parts, the system directly samples breath air and measures ethanol concentration through infrared absorption in a compact sensor chamber, making it suitable for installation in vehicles while maintaining BAC measurement capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides sensitive, long-term ethanol detection in breath, enabling effective BAC measurement without physical contact, suitable for on-board vehicle use, with improved sensitivity and accuracy to detect intoxication levels.
Implementation Method 1
An infrared light source and infrared detector are used
Implementation Method 2
The infrared light source emits infrared light
Data Source
AI summary
A chemical vapor sensor system and method are provided, wherein the system includes an air input device, a light source, a detector, a sample chamber, and a processor. The air input device includes at least a sample input port, a reference input port, and an output port. The light source emits light, and the detector receives at least a portion of the emitted light. The sample chamber is in fluid communication with the output port, wherein the air alternatively enters the air input device from the sample input port and the reference input port and enters the sample chamber. The processor receives an output signal from the detector based upon a detection of at least carbon dioxide and ethanol in the air in the sample chamber, wherein the processor determines a blood alcohol content of a person whose breath was received in the sample input port.