Arduino Code for Level Monitoring using Buzzer

hardware/Arduino_Level_Buzzer_Code.ino

@@ -0,0 +1,63 @@
+#define trigPin 8 //ultrasonic sensor
+#define echoPin 9
+#include <LiquidCrystal.h>
+
+LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
+int BUZZER = 10 ;
+
+void setup(){
+      int duration,distance,percentage,heightTank;
+      Serial.begin (9600);
+      pinMode(trigPin,OUTPUT);
+      pinMode(echoPin,INPUT);
+      lcd.begin(16,2);
+      lcd.print("HELLO");
+        pinMode(BUZZER,OUTPUT);
+}
+
+void loop(){
+      int duration,distance,percentage,heightTank,deviation;
+      // We can change the next 2 lines.
+      // The first one is the max. level of the water.
+      // The next one is how high the sensor is above that max. level.
+      heightTank=65;
+      deviation=4;
+
+      digitalWrite(trigPin,HIGH);
+      delayMicroseconds(1000);
+      digitalWrite(trigPin,LOW);
+      duration=pulseIn(echoPin,HIGH);
+      distance=(duration/2)/29.1;
+      percentage=100-(((distance-deviation)*100)/heightTank);
+      Serial.println(distance);
+      Serial.println(percentage);
+      lcd.clear();
+      lcd.setCursor(0,0);
+      lcd.print("Current tank");
+      //lcd.print(distance);
+      //lcd.print(" cm");
+      lcd.setCursor(0,1);
+      lcd.print("level: ");
+      lcd.print(percentage);
+      lcd.print(" %");
+      delay(1000);
+
+      digitalWrite(BUZZER,HIGH);
+     static unsigned long lastBuzzer = 0;
+
+      if(percentage > 99 && lastBuzzer == 0) {
+      lastBuzzer = millis();
+}
+
+      if(percentage > 99) {
+      if(millis() - lastBuzzer < 15000L) {
+        digitalWrite(BUZZER,HIGH);
+        delay(100);
+        digitalWrite(BUZZER,LOW);
+        delay(100);
+    }
+}      else  {
+       digitalWrite(BUZZER,LOW);
+       lastBuzzer = 0;
+}
+  }