With warmer summer months approaching (at least for us in Australian) it is becoming more important to be sun smart. What better way to start being sun smart than to build your own Arduino UV Meter! Impressively this project also has an inbuilt breathalyser! The keychain uses an OLED display a ESP-1 WiFi module along with a number of sensor to read the UV and blood alcohol level and to display this information back to the user.
If you want to find out more about this impressive project check out the instructable from funelab. The instructions are well explained and include instructions on how to 3D print a case which is perfectly designed for the keychain.