An Alcohol-Sensing Medallion for a Stag Party Weekend

If you choose to go out and enjoy adult beverages with your friends, you’ll of course need to take the proper precautions so that you don’t endanger yourself or others. Probably the best thing would be to plan on a designated driver, cab, or rideshare.

There are, of course, sensors that will tell you how much alcohol is in your system. Relying on these for safety seems like an unwise proposition, but as a bit of a gag — like this medallion that measures alcohol content in units of “Geoffreys” — an amateur breathalyzer could certainly be entertaining.

Creator “No George” built this wearable sensor for Geoffrey, a “special friend who needs supervision on a night out,” to use on his stag weekend. The device is powered by an ESP32 dev board with a LiPo charger, and contains an on/off switch, a button to start things off, and a small port for blowing into. Once it takes a reading, measurements such as “1.6 Geoffreys” are displayed on the E Ink screen (or were, as it broke during use), and there’s a ring of NeoPixel-style LEDs arranged on the outside to make his state more obvious.

While the gadget “is not accurate or consistent,” it does provide “some decent entertainment,” so it seems to have served its purpose before breaking. If nothing else, the bright ring was perhaps useful as a safety light to make Geoffrey more noticeable — if the cape and pink hat weren’t enough. Code for the project is up on GitHub.