Iam not able to transmit do value from code to thingspeak

while uploading the values to thingspeak iam facinga n issue in updating it to thingspeak . Iam able to transmit other values but not the do value. iam attching the code and the issue is underlined in the code. please help me in communicating to thing speak. Except DO value rest all other values are able to transmit to channel.

/*

WriteMultipleFields

Description: Writes values to fields 1,2,3,4 and status in a single ThingSpeak update every 20 seconds.

Hardware: Arduino Uno WiFi Rev2

!!! IMPORTANT - Modify the secrets.h file for this project with your network connection and ThingSpeak channel details. !!!

Note:

- Requires WiFiNINA library.

- This example is written for a network using WPA encryption. For WEP or WPA, change the WiFi.begin() call accordingly.

ThingSpeak ( https://www.thingspeak.com ) is an analytic IoT platform service that allows you to aggregate, visualize, and

analyze live data streams in the cloud. Visit https://www.thingspeak.com to sign up for a free account and create a channel.

Documentation for the ThingSpeak Communication Library for Arduino is in the README.md folder where the library was installed.

See https://www.mathworks.com/help/thingspeak/index.html for the full ThingSpeak documentation.

For licensing information, see the accompanying license file.

Copyright 2020, The MathWorks, Inc.

*/

#include <WiFiNINA.h>

#include "secrets.h"

#include "ThingSpeak.h" // always include thingspeak header file after other header files and custom macros

// the libraries of the ph sensor and varibles defined

#include <Wire.h>

float calibration_value = 21.34-5.5;

int phval = 0;

unsigned long int avgval;

int buffer_arr[10],temp;

// the libraries of tds sensor and varibles are declared here

#include <EEPROM.h>

#include "GravityTDS.h"

#define TdsSensorPin A1

GravityTDS gravityTds;

float temperature = 25,tdsValue = 0;

//the libraries of dissolved oxygen meter are declared here

#include <Arduino.h>

#define DO_PIN A2

#define VREF 5000 //VREF (mv)

#define ADC_RES 1024 //ADC Resolution

//Single-point calibration Mode=0

//Two-point calibration Mode=1

#define TWO_POINT_CALIBRATION 0

#define READ_TEMP (25) //Current water temperature ℃, Or temperature sensor function

//Single point calibration needs to be filled CAL1_V and CAL1_T

#define CAL1_V (1731) //mv

#define CAL1_T (25) //℃

//Two-point calibration needs to be filled CAL2_V and CAL2_T

//CAL1 High temperature point, CAL2 Low temperature point

#define CAL2_V (1300) //mv

#define CAL2_T (15) //℃

const uint16_t DO_Table[41] = {

14460, 14220, 13820, 13440, 13090, 12740, 12420, 12110, 11810, 11530,

11260, 11010, 10770, 10530, 10300, 10080, 9860, 9660, 9460, 9270,

9080, 8900, 8730, 8570, 8410, 8250, 8110, 7960, 7820, 7690,

7560, 7430, 7300, 7180, 7070, 6950, 6840, 6730, 6630, 6530, 6410};

uint8_t Temperaturet;

uint16_t ADC_Raw;

uint16_t ADC_Voltage;

uint16_t DO;

uint16_t dissolved;

int16_t readDO(uint32_t voltage_mv, uint8_t temperature_c)

{

#if TWO_POINT_CALIBRATION == 0

uint16_t V_saturation = (uint32_t)CAL1_V + (uint32_t)35 * temperature_c - (uint32_t)CAL1_T * 35;

return (voltage_mv * DO_Table[temperature_c] / V_saturation);

#else

uint16_t V_saturation = (int16_t)((int8_t)temperature_c - CAL2_T) * ((uint16_t)CAL1_V - CAL2_V) / ((uint8_t)CAL1_T - CAL2_T) + CAL2_V;

return (voltage_mv * DO_Table[temperature_c] / V_saturation);

#endif

}

//wifi and api keys are declared here

char ssid[] = SECRET_SSID; // your network SSID (name)

char pass[] = SECRET_PASS; // your network password

int keyIndex = 0; // your network key Index number (needed only for WEP)

WiFiClient client;

unsigned long myChannelNumber = SECRET_CH_ID;

const char * myWriteAPIKey = SECRET_WRITE_APIKEY;

// Initialize our values

int number1 = 0;

int number2 = random(0,100);

int number3 = random(0,100);

int number4 = random(0,100);

String myStatus = "";

void setup() {

Serial.begin(9600); // Initialize serial

gravityTds.setPin(TdsSensorPin);

gravityTds.setAref(5.0); //reference voltage on ADC, default 5.0V on Arduino UNO

gravityTds.setAdcRange(1024); //1024 for 10bit ADC;4096 for 12bit ADC

gravityTds.begin(); //initialization

while (!Serial) {

; // wait for serial port to connect. Needed for Leonardo native USB port only

}

// check for the WiFi module:

if (WiFi.status() == WL_NO_MODULE) {

Serial.println("Communication with WiFi module failed!");

// don't continue

while (true);

}

String fv = WiFi.firmwareVersion();

if (fv != "1.0.0") {

Serial.println("Please upgrade the firmware");

}

ThingSpeak.begin(client); //Initialize ThingSpeak

}

void loop() {

// Connect or reconnect to WiFi

if(WiFi.status() != WL_CONNECTED){

Serial.print("Attempting to connect to SSID: ");

Serial.println(SECRET_SSID);

while(WiFi.status() != WL_CONNECTED){

WiFi.begin(ssid, pass); // Connect to WPA/WPA2 network. Change this line if using open or WEP network

Serial.print(".");

delay(5000);

}

Serial.println("\nConnected.");

}

// TDS sensor values starts from here

gravityTds.setTemperature(temperature); // set the temperature and execute temperature compensation

gravityTds.update(); //sample and calculate

tdsValue = gravityTds.getTdsValue(); // then get the value

Serial.print(tdsValue,0);

Serial.println("ppm");

delay(1000);

// ph meter values and code here

for(int i=0;i<10;i++)

{

buffer_arr[i]=analogRead(A0);

delay(30);

}

for(int i=0;i<9;i++)

{

for(int j=i+1;j<10;j++)

{

if(buffer_arr[i]>buffer_arr[j])

{

temp=buffer_arr[i];

buffer_arr[i]=buffer_arr[j];

buffer_arr[j]=temp;

}

}

}

avgval=0;

for(int i=2;i<8;i++)

avgval+=buffer_arr[i];

float volt=(float)avgval*5.0/1024/6;

float ph_act = -5.70 * volt + calibration_value;

Serial.println(ph_act);

delay(1000);

// dissolved oxygen meter starts from here

Temperaturet = (uint8_t)READ_TEMP;

ADC_Raw = analogRead(DO_PIN);

ADC_Voltage = uint32_t(VREF) * ADC_Raw / ADC_RES;

Serial.print("Temperaturet:\t" + String(Temperaturet) + "\t");

Serial.print("ADC RAW:\t" + String(ADC_Raw) + "\t");

Serial.print("ADC Voltage:\t" + String(ADC_Voltage) + "\t");

Serial.println("DO:\t" + String(readDO(ADC_Voltage, Temperaturet)) + "\t");

delay(1000);

// set the fields with the values

ThingSpeak.setField(1, ph_act);

ThingSpeak.setField(2, tdsValue);

ThingSpeak.setField(3, float(DO));

ThingSpeak.setField(4, Temperaturet);

// figure out the status message

if(number1 > number2){

myStatus = String("field1 is greater than field2");

}

else if(number1 < number2){

myStatus = String("field1 is less than field2");

}

else{

myStatus = String("field1 equals field2");

}

// set the status

ThingSpeak.setStatus(myStatus);

// write to the ThingSpeak channel

int x = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);

if(x == 200){

Serial.println("Channel update successful.");

}

else{

Serial.println("Problem updating channel. HTTP error code " + String(x));

}

// change the values

number1++;

if(number1 > 99){

number1 = 0;

}

number2 = random(0,100);

number3 = random(0,100);

number4 = random(0,100);

delay(15000); // Wait 20 seconds to update the channel again

}

Answer 1

[NAGUBATHULA SATYA SRIRAM]

cleared the issue Just declared DO value and transmitted the value.

[Christopher Stapels]

Thanks for letting us know, glad to hear you got it working.

[WAN MUHAMAD BAQIR BIN MAHDI]

hi, can u share with me the new coding where u declared the DO? thank you in advance.