npk_azzah.ino

#include <Wire.h>
#include <RTClib.h>
#include <SD.h>
#include <SoftwareSerial.h>

RTC_DS3231 rtc;
const int chipSelect = 10;
File dataFile;

#define RE 7
#define DE 6

const byte nitro[] = {0x01, 0x03, 0x00, 0x1e, 0x00, 0x01, 0xe4, 0x0c};
const byte phos[] = {0x01, 0x03, 0x00, 0x1f, 0x00, 0x01, 0xb5, 0xcc};
const byte pota[] = {0x01, 0x03, 0x00, 0x20, 0x00, 0x01, 0x85, 0xc0};
byte values[11];
SoftwareSerial mod(2, 3);

void setup() {
  Serial.begin(9600);
  mod.begin(9600);
  pinMode(RE, OUTPUT);
  pinMode(DE, OUTPUT);

  // Set the RTC to the desired date and time
  rtc.begin();
  //rtc.adjust(DateTime(__DATE__, __TIME__)); // Replace with the correct date and time

  // Initialize the SD card
  Serial.print("Initializing SD card...");
  if (!SD.begin(chipSelect)) {
    Serial.println("Initialization failed!");
    while (1);
  }
  Serial.println("Initialization done.");
}

void loop() {
  DateTime now = rtc.now();

  // Print date and time to Serial Monitor
  Serial.print("Date: ");
  Serial.print(now.year(), DEC);
  Serial.print('/');
  Serial.print(now.month(), DEC);
  Serial.print('/');
  Serial.print(now.day(), DEC);
  Serial.print(" Time: ");
  Serial.print(now.hour(), DEC);
  Serial.print(':');
  Serial.print(now.minute(), DEC);
  Serial.print(':');
  Serial.print(now.second(), DEC);
  Serial.println();

  byte val1, val2, val3;
  val1 = nitrogen();
  delay(250);
  val2 = phosphorous();
  delay(250);
  val3 = potassium();
  delay(250);

  Serial.print("Nitrogen: ");
  Serial.print(val1);
  Serial.println(" mg/kg");
  Serial.print("Phosphorous: ");
  Serial.print(val2);
  Serial.println(" mg/kg");
  Serial.print("Potassium: ");
  Serial.print(val3);
  Serial.println(" mg/kg");
  delay(2000);

  // Log data to SD card
  logDataToSDCard(now, val1, val2, val3);
}

byte nitrogen() {
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(10);
  if (mod.write(nitro, sizeof(nitro)) == 8) {
    digitalWrite(DE, LOW);
    digitalWrite(RE, LOW);
    for (byte i = 0; i < 7; i++) {
      values[i] = mod.read();
      Serial.print(values[i], HEX);
    }
    Serial.println();
  }
  return values[4];
}

byte phosphorous() {
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(10);
  if (mod.write(phos, sizeof(phos)) == 8) {
    digitalWrite(DE, LOW);
    digitalWrite(RE, LOW);
    for (byte i = 0; i < 7; i++) {
      values[i] = mod.read();
      Serial.print(values[i], HEX);
    }
    Serial.println();
  }
  return values[4];
}

byte potassium() {
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(10);
  if (mod.write(pota, sizeof(pota)) == 8) {
    digitalWrite(DE, LOW);
    digitalWrite(RE, LOW);
    for (byte i = 0; i < 7; i++) {
      values[i] = mod.read();
      Serial.print(values[i], HEX);
    }
    Serial.println();
  }
  return values[4];
}

void logDataToSDCard(DateTime now, byte val1, byte val2, byte val3) {
  dataFile = SD.open("DATALOG.txt", FILE_WRITE);
  if (dataFile) {
    dataFile.print(now.timestamp());
    dataFile.print(",");
    dataFile.print(now.hour(), DEC);
    dataFile.print(":");
    dataFile.print(now.minute(), DEC);
    dataFile.print(":");
    dataFile.print(now.second(), DEC);
    dataFile.print(",N:");
    dataFile.print(val1);
    dataFile.print(" mg/kg,P:");
    dataFile.print(val2);
    dataFile.print(" mg/kg,K:");
    dataFile.print(val3);
    dataFile.println(" mg/kg");
    dataFile.close();
  } else {
    Serial.println("Error opening file.");
  }
}