Tag Archives: DIY Bathroom Alarm

DIY alarm shames those who don’t wash their hands

Did you know that researchers have found that only two in three people use soap when cleaning their hands, while one in 10 skip the sink altogether? At one time or another, we’ve all come across that sign in a public restroom reminding you (and employees) to wash your hands. Undoubtedly after seeing those signs, you’ve also wondered just how often the message gets ignored. Wonder no more! A recent Maker project has sought out to cure this gross behavior by shaming the 10% who fails to wash their hands upon leaving a bathroom with this alarm powered by an Arduino Uno.


The DIY alarm uses piezo sensors attached the bathroom door, toilet and sink to detect entry, flow of water and whether or not the sink has been used after the toilet was flushed. The ATmega328-powered unit monitors each of these sensors and sounds an alarm if a bathroom patron tries to leave without washing up. More embarrassing? This will alert everyone in the room that the individual didn’t wash their hands.


Lessons learned: Always wash your hands… and there really are endless possibilities when it comes to AVR 8-bit and 32-bit ARM-based Arduino boards.

Want to learn how to make a DIY alarm for your restroom? You can find detailed instructions on the project’s official Instructables page and by watching MAKE’s tutorial video below.