Circuit Documentation

Summary

The circuit in question is designed to monitor and control a water system, featuring sensors for pH, turbidity, temperature, and water level. It includes an Arduino Nano as the central microcontroller, interfaced with various sensors and output devices such as a relay module, a buzzer, an OLED display, a water pump, and a pneumatic solenoid valve. The system reads sensor data, displays values on the OLED, and activates the pump and valve based on predefined threshold values.

Component List

Arduino Nano

• Microcontroller board based on the ATmega328P
• Offers a variety of digital and analog I/O pins
• Used as the central processing unit of the circuit

pH Sensor (ph4502c)

• Measures the pH level of the water
• Outputs an analog signal proportional to the pH level

Turbidity Module

• Measures the turbidity of the water
• Provides an analog output corresponding to the water's turbidity

DS18B20 Temperature Sensor

• Digital temperature sensor
• Measures the temperature of the water

Water Level Sensor

• Detects the water level in a tank or reservoir
• Outputs an analog signal based on the water level

Water Pump

• Electric pump for moving water
• Controlled by the Arduino via a relay

OLED 1.3" Display

• Small screen for displaying sensor readings and status information
• Communicates with the Arduino via I2C protocol

12V Pneumatic Solenoid Valve

• Electrically controlled valve for controlling air or water flow
• Actuated by the Arduino through a relay

12V Battery

• Provides power to the water pump and solenoid valve

1 Channel 5V Relay Module (x2)

• Electrically operated switch that allows the Arduino to control high power devices
• One relay controls the water pump, and the other controls the solenoid valve

Buzzer

• Emits an audible alert under certain conditions
• Controlled directly by the Arduino

Wiring Details

Arduino Nano

• GND connected to the common ground net
• D2 connected to DS18B20 Temperature Sensor OUT
• D3 connected to Relay Module (Solenoid Valve) IN
• D4 connected to Relay Module (Pump) IN
• D5 connected to Buzzer PIN
• 5V connected to the common 5V net
• A5 connected to OLED SCL
• A4 connected to OLED SDA
• A2 connected to Water Level Sensor SIG
• A1 connected to Turbidity Module OUT
• A0 connected to pH Sensor Po

pH Sensor (ph4502c)

• VCC connected to the common 5V net
• G1 and G2 connected to the common ground net
• Po connected to Arduino Nano A0

Turbidity Module

• VCC connected to the common 5V net
• GND connected to the common ground net
• OUT connected to Arduino Nano A1

DS18B20 Temperature Sensor

• VCC connected to the common 5V net
• GND connected to the common ground net
• OUT connected to Arduino Nano D2

Water Level Sensor

• VCC connected to the common 5V net
• GND connected to the common ground net
• SIG connected to Arduino Nano A2

Water Pump

• VCC connected to 12V Battery (+)
• GND connected to Relay Module (Pump) N.O.

OLED 1.3" Display

• VCC connected to the common 5V net
• GND connected to the common ground net
• SCL connected to Arduino Nano A5
• SDA connected to Arduino Nano A4

12V Pneumatic Solenoid Valve

• VCC connected to Relay Module (Solenoid Valve) N.O.
• GND connected to 12V Battery (-)

12V Battery

• + connected to Water Pump VCC and Relay Module (Solenoid Valve) COM
• - connected to Pneumatic Solenoid Valve GND and Relay Module (Pump) COM

1 Channel 5V Relay Module (for Solenoid Valve)

• VCC+ connected to the common 5V net
• VCC- (GND) connected to the common ground net
• IN connected to Arduino Nano D3
• N.O. connected to Pneumatic Solenoid Valve VCC
• COM connected to 12V Battery (+)

1 Channel 5V Relay Module (for Pump)

• VCC+ connected to the common 5V net
• VCC- (GND) connected to the common ground net
• IN connected to Arduino Nano D4
• N.O. connected to Water Pump GND
• COM connected to 12V Battery (-)

Buzzer

• PIN connected to Arduino Nano D5
• GND connected to the common ground net

Documented Code

#include <Wire.h>                        // For OLED Display
#include <Adafruit_GFX.h>                 // For OLED Display
#include <Adafruit_SSD1306.h>             // For OLED Display
#include <OneWire.h>                      // For DS18B20 Temperature Sensor
#include <DallasTemperature.h>            // For DS18B20 Temperature Sensor

#define SCREEN_WIDTH 128                  // OLED display width
#define SCREEN_HEIGHT 64                  // OLED display height
#define OLED_RESET -1                     // Reset pin (not used)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Pin Definitions
#define PH_SENSOR_PIN A0                  // pH Sensor connected to A0
#define TURBIDITY_SENSOR_PIN A1           // Turbidity Sensor connected to A1
#define WATER_LEVEL_SENSOR_PIN A2         // Water Level Sensor connected to A2
#define TEMP_SENSOR_PIN 2                 // DS18B20 Temperature Sensor on digital pin 2
#define RELAY_SOLENOID_PIN 3              // Relay for Solenoid Valve on digital pin 3
#define RELAY_PUMP_PIN 4                  // Relay for Pump on digital pin 4
#define BUZZER_PIN 5                      // Buzzer connected to digital pin 5

// DS18B20 Sensor Setup
OneWire oneWire(TEMP_SENSOR_PIN);
DallasTemperature sensors(&oneWire);

// Threshold values (You can adjust these based on your requirements)
float pHThresholdLow = 6.5;               // Lower pH threshold
float pHThresholdHigh = 8.0;              // Upper pH threshold
int turbidityThreshold = 300;             // Turbidity threshold (analog value)
int waterLevelThreshold = 500;            // Water level threshold (analog value)

// Variables
float pHValue;
int turbidityValue;
int waterLevelValue;
float temperatureValue;

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);

  // Initialize the OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {  // Initialize OLED with I2C address 0x3C
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);  // Loop forever if the display initialization fails
  }
  
  // Clear the display
  display.clearDisplay();
  display.display();

  // Initialize the DS18B20 temperature sensor
  sensors.begin();

  // Set pin modes for the relay, buzzer, etc.
  pinMode(RELAY_SOLENOID_PIN, OUTPUT);
  pinMode(RELAY_PUMP_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  // Turn off relays and buzzer at startup
  digitalWrite(RELAY_SOLENOID_PIN, LOW);
  digitalWrite(RELAY_PUMP_PIN, LOW);
  digitalWrite(BUZZER_PIN, LOW);
}

void loop() {
  // Read sensor values
  pHValue = analogRead(PH_SENSOR_PIN);
  turbidityValue = analogRead(TURBIDITY_SENSOR_PIN);
  waterLevelValue = analogRead(WATER_LEVEL_SENSOR_PIN);

  // Get temperature readings
  sensors.requestTemperatures();
  temperatureValue = sensors.getTempCByIndex(0);

  // Display readings on the OLED
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);

  display.print("pH: ");
  display.println(pHValue);

  display.print("Turbidity: ");
  display.println(turbidityValue);

  display.print("Water Level: ");
  display.println(waterLevelValue);

  display.print("Temperature: ");
  display.println(temperatureValue);

  display.display();

  // Control relays and buzzer based on thresholds
  if (pHValue < pHThresholdLow || pHValue > pHThresholdHigh || turbidityValue > turbidityThreshold) {
    digitalWrite(RELAY_SOLENOID_PIN, HIGH);  // Open solenoid valve
    digitalWrite(BUZZER_PIN, HIGH);          // Turn on buz