Based on fuzzy control technology,this paper uses AT89C51 microcontroller to design a kind of intelligent ultrasonic humidifier.The hardware part mainly includes the power supply conversion circuit,the water shortage protection circuit,the oscillation circuit,the reset circuit,the key circuit,the temperature sensor and the display module design.The humidity of humidifier can be set through an external button.The humidity and the humidity set can be seen through the display module.Relying on the fuzzy control technology can avoid the adjusting difficulty of the traditional humidifier.This techn...