#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Wire.begin(23, 22);
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
}

void loop() {
  
  int nitrogen = analogRead(32); 
  int phosphorus = analogRead(33); 
  int potassium = analogRead(34); 

  float nitrogenPercentage = (float(nitrogen) / 1023.0) * 100.0;
  float phosphorusPercentage = (float(phosphorus) / 1023.0) * 100.0;
  float potassiumPercentage = (float(potassium) / 1023.0) * 100.0;

  // Read soil moisture value
  int16_t moistureValue = analogRead(35); 
  float moisturePercentage = (float(moistureValue) / 1023.0) * 100.0;
  String moistureStatus = moisturePercentage < 15.0 ? "DRY" : moisturePercentage > 80.0 ? "WET" : "OK";

  // Display NPK Levels
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("N:");
  lcd.print(nitrogenPercentage, 1);
  lcd.print(" P:");
  lcd.print(phosphorusPercentage, 1);
  lcd.setCursor(0, 1);
  lcd.print(" K:");
  lcd.print(potassiumPercentage, 1);

  delay(2000);


  lcd.clear();
  lcd.print("Soil: ");
  lcd.print(moistureStatus);
  lcd.setCursor(0, 1);
  lcd.print("Moisture: ");
  lcd.setCursor(10, 1);
  lcd.print(moisturePercentage, 1); 

  delay(2000);
}


soil_sensor.ino

diagram.json

#include "wokwi-api.h"
#include <stdio.h>
#include <stdlib.h>

typedef struct {
  pin_t pin;
  float moisture;
} chip_data_t;

void chip_timer_callback(void *data) 
{
  chip_data_t *chip_data = (chip_data_t*)data;
  float moisture = attr_read(chip_data->moisture);
  float volts = 5 * (moisture / 4096.0);
  pin_dac_write(chip_data->pin, volts);
}

void chip_init() 
{
  chip_data_t *chip_data = (chip_data_t*)malloc(sizeof(chip_data_t));
  chip_data->moisture = attr_init("moisture", 2910.0);
  chip_data->pin = pin_init("A0", ANALOG);

  const timer_config_t config = 
  {
    .callback = chip_timer_callback,
    .user_data = chip_data,
  };

  timer_t timer_id = timer_init(&config);
  timer_start(timer_id, 1000, true);
}


soil_sensor.chip.c

Soil Sensor

soil_sensor.chip.json

# Wokwi Library List
# See https://docs.wokwi.com/guides/libraries

# Automatically added based on includes:
LiquidCrystal I2C
# ---
ArduinoJson


libraries.txt

NPK Sensor

npk.chip.json

#include "wokwi-api.h"
#include <stdio.h>
#include <stdlib.h>

typedef struct {
  pin_t nitrogen_pin;
  pin_t phosphorus_pin;
  pin_t potassium_pin;
  float nitrogen_level;
  float phosphorus_level;
  float potassium_level;
} chip_data_t;

void chip_timer_callback(void *data) {
  chip_data_t *chip_data = (chip_data_t*)data;
  
  float nitrogen = attr_read(chip_data->nitrogen_level);
  float phosphorus = attr_read(chip_data->phosphorus_level);
  float potassium = attr_read(chip_data->potassium_level);
  
  float nitrogen_volts = 5 * (nitrogen / 1023.0);
  float phosphorus_volts = 5 * (phosphorus / 1023.0);
  float potassium_volts = 5 * (potassium / 1023.0);
  
  pin_dac_write(chip_data->nitrogen_pin, nitrogen_volts);
  pin_dac_write(chip_data->phosphorus_pin, phosphorus_volts);
  pin_dac_write(chip_data->potassium_pin, potassium_volts);
}

void chip_init() {
  chip_data_t *chip_data = (chip_data_t*)malloc(sizeof(chip_data_t));
  chip_data->nitrogen_level = attr_init("nitrogen", 400.0);
  chip_data->phosphorus_level = attr_init("phosphorus", 300.0);
  chip_data->potassium_level = attr_init("potassium", 200.0);
  
  chip_data->nitrogen_pin = pin_init("Nitrogen", ANALOG);
  chip_data->phosphorus_pin = pin_init("Phosphorus", ANALOG);
  chip_data->potassium_pin = pin_init("Potassium", ANALOG);

  const timer_config_t config = {
    .callback = chip_timer_callback,
    .user_data = chip_data,
  };

  timer_t timer_id = timer_init(&config);
  timer_start(timer_id, 1000, true);
}
