6 in 1 JXCT Multi-parameter Soil Sensor using Arduino Nano

Other Hardware Sensors
69

Another problem that I encounter is when I'm using the display codes for the OLED. I get nothing from the Serial Monitor and the OLED is not lighting up.

Here is my updated code:

#include <AltSoftSerial.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
 
#define SCREEN_WIDTH 128    // OLED display width, in pixels
#define SCREEN_HEIGHT 64    // OLED display height, in pixels
#define OLED_RESET -1       // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
 
// RO to pin 8 & DI to pin 9 when using AltSoftSerial
#define RE 6
#define DE 7
 
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};

const byte ph[] = { 0x01, 0x03, 0x00, 0x06, 0x00, 0x01, 0x64, 0x0b };  // New
const byte mois[] = { 0x01, 0x03, 0x00, 0x12, 0x00, 0x01, 0x24, 0x0F };
const byte temp[] = { 0x01, 0x03, 0x00, 0x01, 0x00, 0x01, 0xD5, 0xCA }; 
 
byte values[11];
AltSoftSerial mod;

float soil_ph = 0.0, soil_moisture = 0.0, soil_temp = 0.0;
byte val1 = 0, val2 = 0, val3 = 0, val4 = 0, val5 = 0, val6 = 0;
 
void setup() {
  Serial.begin(9600);
  mod.begin(4800);
  pinMode(RE, OUTPUT);
  pinMode(DE, OUTPUT);
 
  // put RS-485 into receive mode
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);
 
  //Initializing and Configuring OLED display
//  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); //initialize with the I2C addr 0x3C (128x64)
//  delay(500);
//  display.clearDisplay();
//  display.setCursor(25, 15);
//  display.setTextSize(1);
//  display.setTextColor(WHITE);
//  display.println("Soil NPK Sensor");
//  display.setCursor(25, 35);
//  display.setTextSize(1);
//  display.print("Initializing");
//  display.display();
//  delay(3000);
}
 
void loop() {
  byte val1, val2, val3, val4, val5, val6;
  val1 = nitrogen();
  delay(300);
  val2 = phosphorous();
  delay(300);
  val3 = potassium();
  delay(300);
  val4 = phydrogen() / 10;  // New
  soil_ph = val4;
  delay(300);
  val5 = moisture();
  soil_moisture = val5 / 10.0;
  delay(300);
  val6 = temperature();
  soil_temp = temperature() / 10.0;  // New
  delay(300);

  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");
  Serial.print("ph: ");  // New
  Serial.print(soil_ph);
  Serial.println(" ph");
  Serial.print("Moisture: ");
  Serial.print(soil_moisture);
  Serial.println(" %");  //
  Serial.print("Temperature: ");
  Serial.print(soil_temp);
  Serial.println(" C");
  Serial.println();  // New
  delay(2000);

//  display.clearDisplay();
//
//  display.setTextSize(1);
//  display.setCursor(0, 5);
//  display.print("N: ");
//  display.print(val1);
//  display.setTextSize(1);
//  display.print(" mg/kg");
//
//  display.setTextSize(1);
//  display.setCursor(0, 15);
//  display.print("P: ");
//  display.print(val2);
//  display.setTextSize(1);
//  display.print(" mg/kg");
//
//  display.setTextSize(1);
//  display.setCursor(0, 25);
//  display.print("K: ");
//  display.print(val3);
//  display.setTextSize(1);
//  display.print(" mg/kg");
//
//  display.setTextSize(1); // New
//  display.setCursor(0, 35);
//  display.print("pH: ");
//  display.print(soil_ph);
//  display.setTextSize(1);
//  display.print(" pH");
//
//  display.setTextSize(1);
//  display.setCursor(0, 45);
//  display.print("Moisture: ");
//  display.print(soil_moisture);
//  display.setTextSize(1);
//  display.print(" %");
//
//  display.setTextSize(1);
//  display.setCursor(0, 55);
//  display.print("Temperature: ");
//  display.print(soil_temp);
//  display.setTextSize(1);
//  display.print(" C"); // New
//
//  display.display();
}
 
byte nitrogen() {
  // clear the receive buffer
  mod.flushInput();
 
  // switch RS-485 to transmit mode
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(1);
 
  // write out the message
  for (uint8_t i = 0; i < sizeof(nitro); i++ ) mod.write( nitro[i] );
 
  // wait for the transmission to complete
  mod.flush();
  
  // switching RS485 to receive mode
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);
 
  // delay to allow response bytes to be received!
  delay(200);
 
  // read in the received bytes
  for (byte i = 0; i < 7; i++) {
    values[i] = mod.read();
    Serial.print(values[i], HEX);
    Serial.print(' ');
  }
  return values[4];
}
 
byte phosphorous() {
  mod.flushInput();
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(1);
  for (uint8_t i = 0; i < sizeof(phos); i++ ) mod.write( phos[i] );
  mod.flush();
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);
// delay to allow response bytes to be received!
  delay(200);
  for (byte i = 0; i < 7; i++) {
    values[i] = mod.read();
    Serial.print(values[i], HEX);
    Serial.print(' ');
  }
  return values[4];
}
 
byte potassium() {
  mod.flushInput();
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(1);
  for (uint8_t i = 0; i < sizeof(pota); i++ ) mod.write( pota[i] );
  mod.flush();
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);
// delay to allow response bytes to be received!
  delay(200);
  for (byte i = 0; i < 7; i++) {
    values[i] = mod.read();
    Serial.print(values[i], HEX);
    Serial.print(' ');
  }
  return values[4];
}

byte phydrogen() {
  // clear the receive buffer
  mod.flush();
  // switch RS-485 to transmit mode
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(1);

  // write out the message
  for (uint8_t i = 0; i < sizeof(ph); i++) mod.write(ph[i]);

  // wait for the transmission to complete
  mod.flush();

  // switching RS485 to receive mode
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);

  // delay to allow response bytes to be received!
  delay(1000);

  // read in the received bytes
  for (byte i = 0; i < 7; i++) {
    values[i] = mod.read();
    Serial.print(values[i], HEX);
    Serial.print(' ');
  }
  return values[4];
}

byte moisture() {
  // clear the receive buffer
  mod.flush();

  // switch RS-485 to transmit mode
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(1);

  // write out the message
  for (uint8_t i = 0; i < sizeof(mois); i++) mod.write(mois[i]);

  // wait for the transmission to complete
  mod.flush();

  // switching RS485 to receive mode
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);

  // delay to allow response bytes to be received!
  delay(1000);

  // read in the received bytes
  for (byte i = 0; i < 7; i++) {
    values[i] = mod.read();
    Serial.print(values[i], HEX);
    Serial.print(' ');
  }
  return values[4];
}

byte temperature() {
  // clear the receive buffer
  mod.flush();

  // switch RS-485 to transmit mode
  digitalWrite(DE, HIGH);
  digitalWrite(RE, HIGH);
  delay(1);

  // write out the message
  for (uint8_t i = 0; i < sizeof(temp); i++) mod.write(temp[i]);

  // wait for the transmission to complete
  mod.flush();

  // switching RS485 to receive mode
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);

  // delay to allow response bytes to be received!
  delay(1000);

  // read in the received bytes
  for (byte i = 0; i < 7; i++) {
    values[i] = mod.read();
    Serial.print(values[i], HEX);
    Serial.print(' ');
  }
  return values[3] << 8 | values[4];
}