Passive Buzzer Module

soil humidity module to the environmental humidity is the most sensitive, generally used to detect soil moisture.
module in soil moisture can not reach the setting threshold, DO mouth output high level, when soil moisture more than setting threshold, module D0 output low level;
small plate digital output D0 can be directly connected with the single chip microcomputer, through the single chip microcomputer to detect the high and low level, thus to detect soil moisture;