Circuit Documentation

Summary

This circuit is designed to monitor plant health by measuring soil moisture and environmental conditions. It uses an ESP32 microcontroller to read data from a humidity sensor and an ultrasonic sensor, control a water pump via a relay module, and communicate with a Blynk application for remote monitoring. The system is powered by a 2x 18650 battery pack.

Component List

Humidity Sensor (YL-69)

• Measures the moisture level in the soil.
• Pins: A0 (Analog Output), D0 (Digital Output), GND (Ground), VCC (Power Supply).

Water Pump

• Pumps water to the plant when activated.
• Pins: Positive (Power Supply), Negative (Ground).

Relay Module (1 Channel)

• Acts as an electrically operated switch to control the water pump.
• Pins: S (Signal), 5V (Power Supply), GND (Ground), NC (Normally Closed), COM (Common), NO (Normally Open).

ESP32 - Expansion Board

• The main microcontroller unit that controls the sensors, relay, and communicates with the Blynk app.
• Pins: Numerous GPIOs, Power (3.3V, 5V), Ground (G), Enable (EN), Voltage (VP, VN), Serial (TX0, RX0).

2x 18650 Battery Pack

• Provides power to the circuit.
• Pins: VCC (Power Supply), GND (Ground).

HC-SR04 Ultrasonic Sensor

• Measures the distance to an object, used here for additional plant monitoring.
• Pins: VCC (Power Supply), TRIG (Trigger), ECHO (Echo), GND (Ground).

Wiring Details

Humidity Sensor (YL-69)

• A0 -> ESP32 VP (Analog Pin)
• VCC -> ESP32 V (Power Supply)
• GND -> ESP32 G (Ground)

Water Pump

• Positive -> Relay Module COM (Common)
• Negative -> ESP32 G (Ground)

Relay Module (1 Channel)

• S -> ESP32 D23 (Digital Pin)
• 5V -> ESP32 V (Power Supply)
• GND -> ESP32 G (Ground)
• NO -> ESP32 VCC (Power Supply)
• COM -> Water Pump Positive

ESP32 - Expansion Board

• VP -> Humidity Sensor A0
• D23 -> Relay Module S
• D19 -> HC-SR04 TRIG
• VCC -> 2x 18650 VCC
• G -> Water Pump Negative, Relay Module GND, HC-SR04 GND, Humidity Sensor GND
• V -> Humidity Sensor VCC, Relay Module 5V, HC-SR04 VCC

2x 18650 Battery Pack

• VCC -> ESP32 VCC
• GND -> ESP32 G

HC-SR04 Ultrasonic Sensor

• VCC -> ESP32 V (Power Supply)
• TRIG -> ESP32 D19 (Digital Pin)
• ECHO -> Not connected in this configuration
• GND -> ESP32 G (Ground)

Documented Code

#define BLYNK_TEMPLATE_ID "TMPL6rlQf3Kxk"
#define BLYNK_TEMPLATE_NAME "plant monitoring sistem"

/* Connections
Relay: GPIO23
Btn:   GPIO27
Soil:  GPIO36 (VP)
PIR:   GPIO18
SDA:   GPIO21
SCL:   GPIO22
Temp:  GPIO19
*/

// Include the library files
#include <LiquidCrystal_I2C.h>
#define BLYNK_PRINT Serial
#include <WiFi.h>
#include <BlynkSimpleEsp32.h>
#include <DHT.h>

// Initialize the LCD display
LiquidCrystal_I2C lcd(0x3F, 16, 2);

char auth[] = "YourAuthToken";  // Enter your Blynk Auth token
char ssid[] = "YourSSID";  // Enter your WIFI SSID
char pass[] = "YourPassword";  // Enter your WIFI Password

DHT dht(19, DHT22);  // (DHT sensor pin, sensor type) GPIO19 DHT22 Temperature Sensor
BlynkTimer timer;

// Define component pins
#define soil 36  // GPIO36 (VP) for Soil Moisture Sensor
#define PIR 18   // GPIO18 for PIR Motion Sensor
int PIR_ToggleValue;

void checkPhysicalButton();
int relay1State = LOW;
int pushButton1State = HIGH;
#define RELAY_PIN_1 23       // GPIO23 for Relay
#define PUSH_BUTTON_1 27     // GPIO27 for Button
#define VPIN_BUTTON_1 V12 

// Create three variables for pressure
double T, P;
char status;

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);  // Initialize the LCD with 16 columns and 2 rows
  lcd.backlight();
  pinMode(PIR, INPUT);

  pinMode(RELAY_PIN_1, OUTPUT);
  digitalWrite(RELAY_PIN_1, LOW);
  pinMode(PUSH_BUTTON_1, INPUT_PULLUP);
  digitalWrite(RELAY_PIN_1, relay1State);

  Blynk.begin(auth, ssid, pass, "blynk.cloud", 80);
  dht.begin();

  lcd.setCursor(0, 0);
  lcd.print("  Initializing  ");
  for (int a = 5; a <= 10; a++) {
    lcd.setCursor(a, 1);
    lcd.print(".");
    delay(500);
  }
  lcd.clear();
  lcd.setCursor(11, 1);
  lcd.print("W:OFF");
  
  // Call the function
  timer.setInterval(100L, soilMoistureSensor);
  timer.setInterval(100L, DHT22sensor);
  timer.setInterval(500L, checkPhysicalButton);
}

// Get the DHT22 sensor values
void DHT22sensor() {
  float h = dht.readHumidity();
  float t = dht.readTemperature();

  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  Blynk.virtualWrite(V0, t);
  Blynk.virtualWrite(V1, h);

  lcd.setCursor(0, 0);
  lcd.print("T:");
  lcd.print(t);

  lcd.setCursor(8, 0);
  lcd.print("H:");
  lcd.print(h);
}

// Get the soil moisture values
void soilMoistureSensor() {
  int value = analogRead(soil);
  value = map(value, 0, 4095, 0, 100);  // ESP32 has a 12-bit ADC
  value = (value - 100) * -1;

  Blynk.virtualWrite(V3, value);
  lcd.setCursor(0, 1);
  lcd.print("S:");
  lcd.print(value);
  lcd.print(" ");
}

// Get the PIR sensor values
void PIRsensor() {
  bool value = digitalRead(PIR);
  if (value) {
    Blynk.logEvent("pirmotion", "WARNING! Motion Detected!"); // Enter your Event Name
    WidgetLED LED(V5);
    LED.on();
  } else {
    WidgetLED LED(V5);
    LED.off();
  }
}

BLYNK_WRITE(V6)
{
 PIR_ToggleValue = param.asInt();  
}

BLYNK_CONNECTED() {
  // Request the latest state from the server
  Blynk.syncVirtual(VPIN_BUTTON_1);
}

BLYNK_WRITE(VPIN_BUTTON_1) {
  relay1State = param.asInt();
  digitalWrite(RELAY_PIN_1, relay1State);
}

void checkPhysicalButton() {
  if (digitalRead(PUSH_BUTTON_1) == LOW) {
    // pushButton1State is used to avoid sequential toggles
    if (pushButton1State != LOW) {
      // Toggle Relay state
      relay1State = !relay1State;
      digitalWrite(RELAY_PIN_1, relay1State);
      // Update Button Widget
      Blynk.virtualWrite(VPIN_BUTTON_1, relay1State);
    }
    pushButton1State = LOW;
  } else {
    pushButton1State = HIGH;
  }
}

void loop() {
  if (PIR_ToggleValue == 1) {
    lcd.setCursor(5, 1);
    lcd.print("M:ON ");
    PIRsensor();
  } else {
    lcd.setCursor(5, 1);
    lcd.print("M:OFF");
    WidgetLED LED(V5);
    LED.off();
  }

  if (relay1State == HIGH) {
    lcd.setCursor(11, 1);
    lcd.print("W:ON ");
  } else if (relay1State == LOW) {
    lcd.setCursor(11, 1);
    lcd.print("W:OFF");
  }

  Blynk.run();  // Run the Blynk library
  timer.run();  // Run the Blynk timer
}

Note: Replace YourAuthToken, YourSSID, and YourPassword with your actual Blynk Auth token, WiFi SSID, and WiFi password, respectively.