This article was taken from the May 2015 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
How we tested
Three breathalysers were tested at 0.8 blood alcohol content (BAC), the limit in England, Wales and Northern Ireland, and at 0.5 BAC, the limit in Scotland and France. An ethanol and distilled-water mixture was used to attain even readings, and results were checked against a police-spec Dräger Alcotest 6510 breathalyser.
AlcoSense Elite
The AlcoSense Elite has an auto–clean mechanism that blows out any boozy breath following each use. After taking 19 seconds to warm up, it delivered a reading of 0.76 when tested with the 0.8 BAC solution – the closest of any to the police-grade device. Blown through with the lesser 0.5 BAC, it returned an exact reading. What's its secret? The higher voltage improves its accuracy. 9/10 £59.99
0.8 BAC solution 0.76 BAC 0.5 BAC solution 0.5 BAC Batteries required 3 x AAA
Breathometer
This fits into a smartphone's headphone jack to transform your iOS or Android device into a personal breathalyser. Just follow the on-screen instructions and breathe. The concept is clever, but the execution is poor. You don't breathe directly into this device; rather, your mouth needs to be 5cm away, and you blow towards it. The readings were dangerously low, so this one is best avoided. 3/10 $49.99 (£32) breathometer.com
AlcoProof Breathalyser
In France, the law demands all drivers carry blood-alcohol equipment in their vehicles. The AlcoProof uses potassium dichromate crystals to measure BAC, turning green as they oxidise in the presence of alcohol. As it's designed to detect the French alcohol limit, there is no indicator for 0.8 BAC. But with the 0.5 BAC solution, it sat just above the 0.5 line – an impressive result for something so simple and comparatively inexpensive. 7/10 £6.95 (for two)
This article was originally published by WIRED UK
