How does it work?
The system draws the driver’s exhaled breath into a sensor that measures the concentrations of alcohol and carbon dioxide present. The known quantity of carbon dioxide in human breath serves as an indicator of the degree of dilution of the alcohol concentration in the exhaled air.
Molecules of alcohol and tracers like carbon dioxide absorb infrared light at specific wavelengths. The Senseair device directs infrared light beams on the breath sample and analyses the wavelengths returned in order to quickly and accurately calculate the alcohol concentration.
We have already implemented one touch-free unit, but we continue to move towards a prototype that can be integrated into a vehicle's dashboard by utilising mirrors to reduce the required optical length of the device. The device is highly sensitive and able to analyse diluted breath samples at dilutions expected from a driver’s natural breath plume.
Testing the prototype
To test the prototype under development, the Driver Alcohol Detection System for Safety (DADSS) Research Program has developed a wet gas breath simulator. The simulator blends gases like carbon dioxide, nitrogen, and oxygen with moisture to create an “exhaled breath” that matches the composition, temperature, and pressure of natural human breath. Ethanol can then be added to the breath at various concentrations. In addition, the Senseair prototype will continue to run through a series of tests with human subjects, as well as durability tests in different environmental situations, from temperature shifts to sudden changes in motion, and interferences (e.g. dust or mechanical shock).
Read more about the project at https://www.dadss.org/breath-based-technology/