iPhone & Android Smartphone Breathalyzers have become popular with people who love their technology and who also enjoy drinking. People enjoy smartphone apps and the perceived convenience (or novelty) of carrying around a simple testing device to warn them when they’ve had too much to drink (or to compare numbers and with their drinking buddies).
There are currently no iPhone or Android Smartphone Breathalyzers that come pre-installed from the factory. All of the current iPhone & Android Smartphone Breathalyzers use aftermarket sensors. This is because the iPhone and most Android smartphones do come with microphones, cameras, video cameras, finger print readers, and accelerometer, they do not come with any sensor that can detect ethyl alcohol or ethanol (the type of alcohol humans prefer to drink).
Infrared-based breath analyzer sensors are too large and expensive to be used in a small plug-in adapter suitable for smartphones, so portable breathalyzers must use silicon oxide sensor (also called a semiconductor sensor) or platinum fuel cell sensors. These sensors need to be replaced or re-calibrated every six months to a year. They are also notoriously inaccurate.
Fortune.com ran an interesting story in December of 2014 on mobile breathalyzer testing and conducted informal testing of the Alcohoot Mobile Breathalyzer, BACtrack Mobile, BACtrack Vio, and Breathometer Breeze. What they found was not surprising: The devices were wildly inaccurate. Some overestimated BAC and others underestimated BAC.
The key think to keep in mind with iPhone & Android Smartphone Breathalyzers is that the might be fun at parties or at the bar, but they really provide nothing more than a false sense of security if they are used to attempt to make a decision as to whether or not to drive after drinking. The devices cannot measure mental and physical impairment, and they really do not accurately measure what they claim to be able to measure and that is the difference between a .07 and .08. The difference between those two numbers is only one one-hundredth of a percent (0.01%) and the machines simply aren’t capable of that accuracy. In Oregon, the difference between a .07 BAC and a .08 BAC could mean an administrative license suspension and the presumption of guilt in a criminal charge of DUI.