The hand washing liquid dispenser can distribute the liquid on the hand automatically as soon as the hand is placed at the distributor, and I have used in my project this ultrasonic sensor to sense the presence of a hand at the distributor, and also used the engine Servo, where when the ultrasonic sensor senses the presence of a hand in the appropriate distance the servo rotates at an appropriate angle so that it presses the compressor of the distributor. by Suleiman Alothman
