Mud water dispenser

 code:

#define trigger 5

#define echo 4

#define Relay 6

float time=0,distance=0;

 

void setup()

{

Serial.begin(9600);

 pinMode(trigger,OUTPUT);

 pinMode(echo,INPUT);

 pinMode(Relay,OUTPUT);

 delay(2000);

}

 

void loop()

{

 measure_distance();

 if(distance<5)

 {

   digitalWrite(Relay,LOW);

 }

 else

 {

   digitalWrite(Relay,HIGH);

 }

 delay(500);

}

void measure_distance()

{

 digitalWrite(trigger,LOW);

 delayMicroseconds(2);

 digitalWrite(trigger,HIGH);

 delayMicroseconds(10);

 digitalWrite(trigger,LOW);

 delayMicroseconds(2);

 time=pulseIn(echo,HIGH);

 

 distance=time*200/20000;

}