We don't always have a breathalyser handy. However, our smartphones are never too far away, and soon they could be very useful in the case of alcohol consumption. For almost four months a team of researchers from the University of Pittsburgh tried to find out whether it was possible for a phone to determine one’s blood-alcohol level.To do this, they called on 22 volunteers, all under the age of 21. The participants were not to use drugs during the 24 hours prior to the experiment. In addition, they were not to consume caffeine 4 hours before the test began. How did the experiment work?Each participant consumed a number of caipiroskas (a cocktail made with vodka, lime, and brown sugar) until they reached 0.08% of the legal blood alcohol level in the United States. Once the drinks were finished, each volunteer had a smartphone placed on his or her lower back.Once installed, the phones analysed the participants' gait thanks to an application called ‘Phyphox.’ The scientists then asked them to walk in a straight line before retracing their steps. The results were impressive: in 90% of the cases, the analysis of the gait showed that there was a link between alcohol consumption and the ability to walk straight. This app is still in its infancy, but researchers are optimistic about what comes next. Smartphones may soon be our breathalysers!