Published with permission from the book, DUI/DWI: The History of Driving Under the Influence, David N. Jolly. Outskirts Press (2009)
The DUI Guide: DUI Evidentiary Breath Test Devices
Smith & Wesson, the original manufacturers of the Breathalyzer, began production of a new unit in 1981. The Model 2000 was the company’s first attempt at a breath alcohol machine using the principle of infrared absorption. The Model 2000 also contains a “microprocessor" which programs the machine through a sequence of internal controls during the course of the test.
The machine uses a “balanced light concept" similar to the original Breathalyzer models which is designed to assure that changes in power line voltage should not affect BAC readings. As a result the Model 2000 has both a dual channel design and a split channel design which is used in an attempt to guarantee some measure of specificity for ethyl alcohol and to isolate energy changes which result from the presence of ethyl alcohol in a sample. Unlike the original Breathlyzer model the Model 2000 contains no moving parts, except for the mechanical printout assembly. Both the light filters and the temperature are fixed.
Compared to the original Breathalyzer models the Model 2000 is a sophisticated machine and it is this relative sophistication that is the source of some of its problems. Infrared analysis is a physical measurement and as such it is a non-chemical means of analying a breath sample.
Other potential problems with the Model 2000 is that it may be susceptible to radio frequency interference (RFI) and humidity. Interestingly, prior to the sale of the company to National Draiger the humidity detector was removed from all of its machines. A possible error would be if there was too much humidity in the breath sample a false high reading can result.