The goal of this project was to make use of some old components and to improve my poor Autodesk Inventor skills. I designed a simple 3D printable tank filled with a mixture of alcohol and water.
Dispenser is powered by one Li-Ion cell or from charger.
Proximity of hand is detected by a cheap ultrasonic sensor HC-SR04. PIC16F1786 measures the length of echo pulse from HC-SR04 and activates the pump if the hand is aprox. 4 cm from the sensor. The display shows the number of uses and the voltage of battery.
Enjoy this project?