DIY dispenser for who hand sanitizer
Easy do it yourself solution for a hand sanitizer dispenser. It consists of a mouth shower pump and a ultrasonic sensor controlled by an arduino trinket.
The sensor detects if someone holds his hand below the dispenser. Then a relay is triggered to start the mouth shower pump. To limit the current of the pump it is powered by a LM317. This way any power supply up to 16V will work (consider a heat sink for the LM317 for higher voltages).