You may soon be able to check whether you’re over the legal limit with the help of a temporary tattoo.
A group of nanoengineers from the University of California have developed a tiny wearable device that can check your alcohol level in real time.
Made of flexible wires and electronics that can be stuck onto your skin, the prototype device will keep tabs on your drinking and send your level of wastedness straight to your smartphone.
It works by releasing a chemical onto your skin that makes you produce sweat. This is then analysed for its ethanol content and the results can be monitored on the corresponding app within 10 minutes.
As one of the researchers involve in the project tells Techradar, “one component releases a chemical that stimulates perspiration on the skin below the patch. Another component senses changes in the electrical current flowing through the generated sweat, which measures alcohol levels and sends them to the user’s cell phone."

The device will detect ethanol levels in your sweat that it will use to tell your smartphone how wasted you are (American Chemical Society) Source: American Chemical Society
While still a prototype, initial testing seems positive with a paper published by the American Chemical Society stating that “on-body results with human subjects show distinct differences in the current response before and after alcohol consumption, reflecting the increase of ethanol levels.”
It remains to be seen whether the temporary tattoo will make it to the market, but there are a host of other products - including this wristband - that claim to do the same thing.