7 in 1 Soil Sensor not working properly

Projects Programming
1

Using the JXCT 7 in 1 sensor paired with RS485 and Arduino. It is supposed to give me NPK, Temp, Moisture, EC and PH but I cannot get any values for NPK or EC and I am getting values that don't make sense for PH.

Here is the specs for the sensor https://drive.google.com/file/d/1VcihqE6h_v_EGGeEb5uXc7iv5M9U-5g9/view

Here is my code. Need Guidance.

#include <AltSoftSerial.h>

// RO to pin 8 & DI to pin 9 when using AltSoftSerial
#define RE 6
#define DE 7

const byte temp[] = {0x01,0x03, 0x00, 0x13, 0x00, 0x01, 0x75, 0xcf};//
const byte mois[]  = {0x01,0x03,0x00,0x12,0x00,0x01,0x24,0x0F};
const byte econ[] = {0x01,0x03, 0x00, 0x15, 0x00, 0x01, 0x95, 0xce};
const byte ph[] = {0x01,0x03, 0x00, 0x06, 0x00, 0x01, 0x64, 0x0b};//0x0B64

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];
AltSoftSerial mod;

float envhumidity = 0.0, envtemperature = 0.0, soil_ph = 0.0, soil_mois = 0.0, soil_temp = 0.0;
byte val1 = 0, val2 = 0, val3 = 0, val4 = 0,val5 = 0, val6 = 0, val7 = 0;

void setup() {
  Serial.begin(115200);
  mod.begin(9600);
  pinMode(RE, OUTPUT);
  pinMode(DE, OUTPUT);

  // put RS-485 into receive mode
  digitalWrite(DE, LOW);
  digitalWrite(RE, LOW);

  delay(3000);
}

void loop() {
  val1 = moisture();
  soil_mois = val1/10.0;
  delay(1000);
  soil_temp = temperature()/10.0;
  delay(1000);
  val3 = econduc();
  delay(1000);
  val4 = phydrogen()/10;
  soil_ph = val4;
  delay(1000);
  val5 = nitrogen();
  delay(1000);
  val6 = phosphorous();
  delay(1000);
  val7 = potassium();
  delay(1000);

  Serial.print("Moisture: ");Serial.print(soil_mois);Serial.println(" %");
  delay(1000);
  Serial.print("Temperature: ");Serial.print(soil_temp);Serial.println(" C");
  delay(1000);
  Serial.print("EC: ");Serial.print(val3);Serial.println(" us/cm");
  delay(1000);
  Serial.print("ph: ");Serial.print(soil_ph);Serial.println(" ph");
  delay(1000);
  Serial.print("Nitrogen: "); Serial.print(val5);Serial.println(" mg/kg");
  delay(1000);
  Serial.print("Phosphorous: ");Serial.print(val6);Serial.println(" mg/kg");
  delay(1000);
  Serial.print("Potassium: ");Serial.print(val7);Serial.println(" mg/kg");
  Serial.println();
  delay(3000);
}

byte moisture() {
  // 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(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(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 temperature() {
  // 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(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(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[3]<<8|values[4];
}

byte econduc() {
  // 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(econ); i++) mod.write(econ[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 phydrogen() {
  // 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(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(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 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];
}
2

Hi,
I think this sensor has been a problem for a lot of users.
I'm no expert but if you use the "forum search" in the top right hand of this page you may find some solutions.
Search for JXCT 7 in 1

Hope it helps.. Tom.. :grinning: :+1: :coffee: :australia:

3

Your code is based on a version of my code that I put together before I learnt more about the various NPK sensor variants.

You should start by printing out the raw response messages from the sensor just to make sure that you are getting valid responses, as the code you are using does not carry out all the modbus checks that a proper modbus library would.

Looking at the datasheet you provided, I didn't see a register for K. It's probably a typing error.

I'm on a small screen at the moment so it's difficult to provide links to recent forum discussions, so search for NPK as already suggested.

I would start by trying to receive 1 parameter that you have a good idea if what value should be returned - eg temperature, and get that working first, before adding more parameter requests.

4

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