Hands-free Hand Sanitizer Dispenser

Screenshot of the circuit
Screenshot of the code

With the threat of COVID-19, it is more important than ever to maintain hygiene and prevent the spread of germs through surfaces. The handles of bottles of soap, hand sanitizer, and other similar dispensers are the most susceptible to becoming contaminated and serving as a vector for infectious disease transmission. Thus, our project consists of an Arduino-powered automatic hand sanitizer dispenser. Keep in mind that this project is easily adaptable to many other hands-free uses including bottles of soap, condiment dispensers at restaurants, water fountains, etc.

The circuit consists of a ping sensor as the sensor and a micro servo motor and LED as the actuators. When a user moves their hand close to the ping sensor, the LED will turn on to indicate to them that the motion sensor has been activated. At the same time, the micro servo motor will rotate a full 90 degrees once, pushing down the bottle’s nozzle, dispensing the hand sanitizer, and returning to its original position in a period of about three seconds. This three second process will happen once and only once regardless of whether the user has kept their hand in the original position or moved it repeatedly.

A micro servo motor is particularly useful in this context because the motor will rotate exactly 90 degrees every time, so there is no need to worry about configuring the distance rotated or that the motor will become misaligned over time. By attaching the micro servo directly above the bottle of hand sanitizer (or a similar pump-activated bottle) and pointing the sensor towards the area just below the nozzle, this project is very easy to implement for public or personal use. The system can be placed in a fixed public location (like at the entrance to a restaurant, classroom, or other common space) or simply near the front door of a user’s home. The only requirement is a steady 5V USB power source for the Arduino.