Everyone has that one friend who never knows when to stop. Well now that friend may just have a solution to their drinking habits. Scientists have created a tattoo that can tell you when you have had too much to drink.
The way they do it is by measuring the alcohol level in your sweat. Once the device that is tattooed on you senses the alcohol content it sends a signal to you phone which tells you if you are too drunk. Source
This could greatly impact things like drunk driving, alcoholism, and overdosing. Maybe it could no more effective than a friend telling you when to stop. Regardless there should always be a designated driver.
One problem is that even though the tattoo device can tell you when you have had too much, it can not force you to stop. It is ultimately your choice if you want to continue drinking. I think this type of thing would help people who are trying to watch their alcohol consumption, who know they have little self control. However, it could be really expensive to get the device and many people who would benefit from it are in a lower class and may not be able to afford it.