Design and Retrofitting of a Contactless Hand Washing Machine

ABSTRACT Hand washing is perhaps the most effective way to avoid the transmission of diseases. Within the Department of Electrical/Electronic Engineering, there is a challenge in upholding hand hygiene due to the malfunctioning of automatic handwashing machines, each exhibiting various faults. The automatic hand washing system was successfully designed and implemented using an Arduino Nano, ultrasonic sensor, LED, LCD, buzzer, water pump, soap pump, relay module, and a stable power supply. The system works with the principle, when a user places their hands near the sensor unit, the sensor detects the hands and sends a signal to the control unit. The control unit then activates the relays in the switchboard, which in turn power the water and soap pumps. The display unit shows the current operation (e.g., "awaiting user detection"), and the indicator unit provide additional signals. After the hands are removed or after a set duration, the control unit turns off the pumps and updates the display to indicate that the machine is ready for the next user. The power unit ensures that all components are supplied with the necessary voltage levels throughout the process. The system effectively achieved its goal of providing a touchless hand-washing experience, responding accurately to hand detection, and dispensing the correct amounts of soap and water.