Circuit Documentation

Summary

This circuit is designed to monitor water levels and pH values, providing visual and auditory alerts when water levels exceed a certain threshold. It utilizes an Arduino UNO as the central microcontroller to interface with a water level sensor, a pH sensor module (ph4502c), a buzzer, a servo motor, and a Bluetooth module for potential wireless communication. An LED is also included to provide a visual indication of the water level status.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• It has 14 digital input/output pins, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header, and a reset button.

Water Level Sensor

• A sensor that detects the level of water in a tank or other reservoir.
• It has three pins: SIG (signal), VCC (power), and GND (ground).

Tower Pro SG90 Servo

• A small and lightweight servo motor capable of precise control.
• It has three pins: Signal, +5V, and GND.

Buzzer

• An electronic buzzer for audible alerts.
• It has two pins: PIN (signal input) and GND (ground).

HC-05 Bluetooth Module

• A wireless communication module that allows for Bluetooth connectivity.
• It has six pins: Key, VCC, TXD, RXD, State, and GND.

PH Meter (ph4502c)

• A sensor module used for measuring the pH level of a liquid.
• It has six pins: VCC, G1, G2, Po, Do, and To.

LED: Two Pin (red)

• A basic red LED for visual signaling.
• It has two pins: cathode (-) and anode (+).

Resistor

• A 220 Ohm resistor used to limit current to the LED.
• It has two pins: pin1 and pin2.

Wiring Details

Arduino UNO

• D2 connected to Resistor (for LED control)
• GND connected to common ground net
• D10 connected to Buzzer
• D9 connected to Tower Pro SG90 Servo (Signal)
• 5V connected to common VCC net
• A0 connected to PH Meter (Po)
• A5 connected to Water Level Sensor (SIG)
• D7 connected to Water Level Sensor (VCC)
• D1 connected to HC-05 Bluetooth Module (RXD)
• D0 connected to HC-05 Bluetooth Module (TXD)

Water Level Sensor

• SIG connected to Arduino UNO (A5)
• VCC connected to Arduino UNO (D7)
• GND connected to common ground net

Tower Pro SG90 Servo

• Signal connected to Arduino UNO (D9)
• +5V connected to common VCC net
• GND connected to common ground net

Buzzer

• PIN connected to Arduino UNO (D10)
• GND connected to common ground net

HC-05 Bluetooth Module

• VCC connected to common VCC net
• TXD connected to Arduino UNO (D0)
• RXD connected to Arduino UNO (D1)
• GND connected to common ground net

PH Meter (ph4502c)

• VCC connected to common VCC net
• Po connected to Arduino UNO (A0)
• G1 connected to common ground net

LED: Two Pin (red)

• Cathode connected to common ground net
• Anode connected to Resistor (pin2)

Resistor

• Pin1 connected to Arduino UNO (D2)
• Pin2 connected to LED (anode)

Documented Code

#include <Servo.h>

#define BUZZER_PIN 10  // Pin for the buzzer
#define POWER_PIN   7
#define SIGNAL_PIN  A5
#define THRESHOLD   500
#define LED_PIN     2
#define SERVO_PIN   9  // Pin for the servo motor

Servo servo; // create servo object to control a servo
int value = 0; // variable to store the water level sensor value
int angle = 0; // the current angle of servo motor
const int pHSensorPin = A0;

// Calibration values for pH sensor
const float neutralVoltage = 2.5; // Voltage corresponding to pH 7.0 (adjust based on your measurement)
const float scaleFactor = 3.5;    // pH sensitivity (adjust if necessary)

void setup() {
  Serial.begin(9600);
  pinMode(BUZZER_PIN, OUTPUT);  // set buzzer pin as output
  pinMode(LED_PIN, OUTPUT);      // configure D2 pin as an OUTPUT
  pinMode(POWER_PIN, OUTPUT);    // configure D7 pin as an OUTPUT
  digitalWrite(POWER_PIN, LOW);  // turn the sensor OFF
  digitalWrite(LED_PIN, LOW);    // turn LED OFF
  servo.attach(SERVO_PIN);       // attaches the servo on pin 9 to the servo object
  servo.write(angle);            // initialize the servo at 0 degrees
}

void loop() {
  digitalWrite(POWER_PIN, HIGH);  // turn the water level sensor ON
  value = analogRead(SIGNAL_PIN); // read the analog value from the water level sensor
  digitalWrite(POWER_PIN, LOW);   // turn the sensor OFF

  // Display the water level value on the serial monitor
  Serial.print("Water Level: ");  
  Serial.println(value);          // Print the actual water level value
  
  // Read and display the pH sensor value
  int sensorValue = analogRead(pHSensorPin);  // Read the analog value from the pH sensor
  float voltage = sensorValue * (5.0 / 1023.0); // Convert the analog value to voltage
  
  // Adjust the formula to invert pH scaling
  float pHValue = 7.0 - ((voltage - neutralVoltage) * scaleFactor);
  pHValue = constrain(pHValue, 0.0, 14.0); // Constrain pH value to a valid range
  
  Serial.print("pH Value: ");    // Show the pH value on the serial monitor
  Serial.println(pHValue);

  delay(100);  // wait 100 milliseconds
  
  // Water level detection and actions when the value is greater than THRESHOLD (500)
  if (value > THRESHOLD) {
    Serial.println("AMARAN BANJIR! Air melebihi Paras Normal"); // Custom alert message
    digitalWrite(LED_PIN, HIGH);  // Turn LED ON

    // Calculate the siren speed and frequency range based on the water level
    int beepDelay = map(value, 500, 700, 500, 100);  // Faster beeps as value increases
    int freqMin = map(value, 500, 700, 500, 800);  // Lower frequency increases with water level
    int freqMax = map(value, 500, 700, 1000, 1500);  // Higher frequency increases with water level

    // Create a sweeping siren effect between freqMin and freqMax
    for (int freq = freqMin; freq <= freqMax; freq += 50) {
      tone(BUZZER_PIN, freq);  // Start with low frequency and increase
      delay(beepDelay / 10);   // Shorter delay for smooth frequency sweep
    }
    for (int freq = freqMax; freq >= freqMin; freq -= 50) {
      tone(BUZZER_PIN, freq);  // Decrease frequency to create the siren sweep
      delay(beepDelay / 10);   // Same shorter delay
    }

    // Control the servo to rotate to 180 degrees, then back to 0 degrees
    servo.write(180);  
    delay(500);       // Wait for the servo to reach the position
    servo.write(0);

    // Turn off LED after the sequence
    digitalWrite(LED_PIN, LOW);
  }
  else {
    // Turn off LED and stop the buzzer when the water level is below the threshold
    digitalWrite(LED_PIN, LOW);
    noTone(BUZZER_PIN);  // Stop the buzzer
    servo.write(0);      // Keep the servo at 0 degrees
  }
}

This code is designed to run on the Arduino UNO microcontroller. It initializes the connected devices and enters a loop where it reads the water level and pH values, providing alerts and actuating a servo motor if the water level exceeds a predefined threshold. The code includes comments for clarity and can be adjusted for calibration and sensitivity of the pH sensor.