water level sensor HW-038

				
					#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// OLED screen settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Pin definitions
#define WATER_SENSOR A0
#define RED_LED 2
#define YELLOW_LED 3
#define GREEN_LED 4
#define BUZZER 5

// Modified water level threshold settings（100,150,200）
#define LOW_LEVEL 100     
#define MEDIUM_LEVEL 150  
#define HIGH_LEVEL 200   

// Buzzer parameter
#define BUZZER_LOW_FREQ 800
#define BUZZER_MED_FREQ 1200
#define BUZZER_HIGH_FREQ 1600
#define BUZZER_DURATION 300

// Water level enumeration
enum WaterLevel {
  WATER_NONE,    
  WATER_LOW,    
  WATER_MEDIUM,  
  WATER_HIGH     
};
// Global variables
int sensorValue = 0;
WaterLevel currentLevel = WATER_NONE;
WaterLevel previousLevel = WATER_NONE;
unsigned long lastBlinkTime = 0;
bool redLedState = false;
void setup() {
  // Initialize pin
  pinMode(RED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  digitalWrite(BUZZER, LOW);
  // Initialize serial port
  Serial.begin(9600);
  // Initialize OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  // Display startup information
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Water Level Monitor");
  display.print("Thresholds: ");
  display.print(LOW_LEVEL);
  display.print(",");
  display.print(MEDIUM_LEVEL);
  display.print(",");
  display.println(HIGH_LEVEL);
  display.display();
  turnOffAllLeds();
  delay(2000);
}
void loop() {
  // Read sensor
  sensorValue = analogRead(WATER_SENSOR);
  Serial.print("Sensor: ");
  Serial.println(sensorValue);
  // Determine water level
  currentLevel = getWaterLevel();
  
  // Control LED
  controlTrafficLights(currentLevel);
  // Trigger buzzer when water level changes
  if(currentLevel != previousLevel) {
    triggerBuzzer(currentLevel);
    previousLevel = currentLevel;
  }
  // Update display
  displayWaterLevel();
  delay(100);
}
// Get water level
WaterLevel getWaterLevel() {
  if(sensorValue >= HIGH_LEVEL) {
    return WATER_HIGH;
  } else if(sensorValue >= MEDIUM_LEVEL) {
    return WATER_MEDIUM;
  } else if(sensorValue >= LOW_LEVEL) {
    return WATER_LOW;
  } else {
    return WATER_NONE;
  }
}
// LED control level
void controlTrafficLights(WaterLevel level) {
  switch(level) {
    case WATER_LOW:
      digitalWrite(GREEN_LED, HIGH);
      digitalWrite(YELLOW_LED, LOW);
      digitalWrite(RED_LED, LOW);
      break;
    case WATER_MEDIUM:
      digitalWrite(GREEN_LED, HIGH);
      digitalWrite(YELLOW_LED, HIGH);
      digitalWrite(RED_LED, LOW);
      break;
    case WATER_HIGH:
      if(millis() - lastBlinkTime > 500) {
        redLedState = !redLedState;
        digitalWrite(RED_LED, redLedState);
        digitalWrite(YELLOW_LED, LOW);
        digitalWrite(GREEN_LED, LOW);
        lastBlinkTime = millis();
      }
      break;
    default:
      turnOffAllLeds();
      break;
  }
}
// Turn off all LED
void turnOffAllLeds() {
  digitalWrite(RED_LED, LOW);
  digitalWrite(YELLOW_LED, LOW);
  digitalWrite(GREEN_LED, LOW);
}
// Trigger buzzer
void triggerBuzzer(WaterLevel level) {
  unsigned long startTime = millis();
  unsigned int frequency;
  switch(level) {
    case WATER_LOW: frequency = BUZZER_LOW_FREQ; break;
    case WATER_MEDIUM: frequency = BUZZER_MED_FREQ; break;
    case WATER_HIGH: frequency = BUZZER_HIGH_FREQ; break;
    default: return;
  }
  // Generate sound
  while(millis() - startTime < BUZZER_DURATION) {
    digitalWrite(BUZZER, HIGH);
    delayMicroseconds(500000 / frequency);
    digitalWrite(BUZZER, LOW);
    delayMicroseconds(500000 / frequency);
  }
  digitalWrite(BUZZER, LOW);
}
// OLED display
void displayWaterLevel() {
  display.clearDisplay();
  
  // Display value
  display.setTextSize(2);
  display.setCursor(0, 10);
  display.print("Value: ");
  display.println(sensorValue);
  // Display water level status
  display.setTextSize(1);
  display.setCursor(0, 35);
  display.print("Level: ");
  switch(currentLevel) {
    case WATER_LOW: display.println("LOW"); break;
    case WATER_MEDIUM: display.println("MEDIUM"); break;
    case WATER_HIGH: display.println("HIGH!"); break;
    default: display.println("NONE"); break;
  }
  // Display threshold information
  display.setCursor(0, 50);
  display.print("Thresh: ");
  display.print(LOW_LEVEL);
  display.print(",");
  display.print(MEDIUM_LEVEL);
  display.print(",");
  display.print(HIGH_LEVEL);
  
  display.display();
}