Many law enforcement agencies in the Rochester area conduct breath tests in DWI cases using a machine called the DataMaster, which is manufactured by National Patent Analytical Systems.

While there are a few different versions of the DataMaster currently in use, they all work in essentially the same fashion.

A driver suspected of intoxication will be asked to blow into the machine.

Using computer software, the device measures parameters in the breath sample such as temperature, flow rate, and the amount of air delivered to determine when the air passing through the machine is coming from deep within the driver’s lungs instead of his or her mouth or throat.

Once the machine deems that the breath test sample is appropriate, it uses infrared testing to determine the amount of alcohol present in the sample.

This is accomplished by measuring the amount of interference present in the infrared wavelength centered at 3.44 microns.

3.44 microns is one of the wavelengths that alcohol is known to absorb.

To conduct this measurement, the DataMaster moves a filter into position and measures the decrease in transmission of infrared light in the 3.44 micron range.

After completing the measurement, the device removes the filter and takes another measurement using a filter centered at the nearby wavelength of 3.37 microns.

This second measurement is done to ensure that there is no acetone – which can be present on the breath of diabetics – interfering with the alcohol measurement.

Upon completion of the test, a printer provides a hard copy of the test results.

The breath test can be the most damaging piece of evidence in any DWI case.

If you need an experienced DWI lawyer who understands how the breath test machine works, call us at 585-484-7432.