Hi Everyone. Below is the sketch that I was working with to measure pH using a V1.1 DFRobot pH probe.
/*
Sketch generated by the Arduino IoT Cloud Thing "Untitled"
https://create.arduino.cc/cloud/things/584000aa-aa07-49f8-a3df-3b397cf809a7
Arduino IoT Cloud Variables description
The following variables are automatically generated and updated when changes are made to the Thing
float pHVal;
Variables which are marked as READ/WRITE in the Cloud Thing will also have functions
which are called when their values are changed from the Dashboard.
These functions are generated with the Thing and added at the end of this sketch.
*/
#include "thingProperties.h"
#define SensorPin A2 //pH meter Analog output to Arduino Analog Input 0
#define Offset -2.00 //deviation compensate
#define LED 13
#define samplingInterval 20
#define printInterval 800
#define ArrayLenth 40 //times of collection
int pHArray[ArrayLenth]; //Store the average value of the sensor feedback
int pHArrayIndex=0;
void setup() {
// Initialize serial and wait for port to open:
Serial.begin(9600);
// This delay gives the chance to wait for a Serial Monitor without blocking if none is found
delay(1500);
pinMode(LED,OUTPUT);
Serial.begin(9600);
Serial.println("pH meter experiment!"); //Test the serial monitor
// Defined in thingProperties.h
initProperties();
// Connect to Arduino IoT Cloud
ArduinoCloud.begin(ArduinoIoTPreferredConnection);
/*
The following function allows you to obtain more information
related to the state of network and IoT Cloud connection and errors
the higher number the more granular information you’ll get.
The default is 0 (only errors).
Maximum is 4
*/
setDebugMessageLevel(2);
ArduinoCloud.printDebugInfo();
}
void loop() {
ArduinoCloud.update();
// Your code here
static unsigned long samplingTime = millis();
static unsigned long printTime = millis();
static float pHValue,voltage;
if(millis()-samplingTime > samplingInterval)
{
pHArray[pHArrayIndex++]=analogRead(SensorPin);
if(pHArrayIndex==ArrayLenth)pHArrayIndex=0;
voltage = avergearray(pHArray, ArrayLenth)*3.3/1024;
pHVal= pHValue = 4.75*voltage+Offset;
samplingTime=millis();
}
if(millis() - printTime > printInterval) //Every 800 milliseconds, print a numerical, convert the state of the LED indicator
{
Serial.print("Voltage:");
Serial.print(voltage,2);
Serial.print(" pH value: ");
Serial.println(pHVal,2);
digitalWrite(LED,digitalRead(LED)^1);
printTime=millis();
}
}
double avergearray(int* arr, int number){
int i;
int max,min;
double avg;
long amount=0;
if(number<=0){
Serial.println("Error number for the array to avraging!/n");
return 0;
}
if(number<5){ //less than 5, calculated directly statistics
for(i=0;i<number;i++){
amount+=arr[i];
}
avg = amount/number;
return avg;
}else{
if(arr[0]<arr[1]){
min = arr[0];max=arr[1];
}
else{
min=arr[1];max=arr[0];
}
for(i=2;i<number;i++){
if(arr[i]<min){
amount+=min; //arr<min
min=arr[i];
}else {
if(arr[i]>max){
amount+=max; //arr>max
max=arr[i];
}else{
amount+=arr[i]; //min<=arr<=max
}
}//if
}//for
avg = (double)amount/(number-2);
}//if
return avg;
And the thing.properties tab:
// Code generated by Arduino IoT Cloud, DO NOT EDIT.
#include <ArduinoIoTCloud.h>
#include <Arduino_ConnectionHandler.h>
const char SSID[] = SECRET_SSID; // Network SSID (name)
const char PASS[] = SECRET_OPTIONAL_PASS; // Network password (use for WPA, or use as key for WEP)
float pHVal;
void initProperties(){
ArduinoCloud.addProperty(pHVal, READ, ON_CHANGE, NULL);
}
WiFiConnectionHandler ArduinoIoTPreferredConnection(SSID, PASS);
I am not sure where I am going wrong, because my serial monitor displays the float pHVal accurately.
But when I attempt to read it off the dasboard, I get N/A
Hope you could help me out, thank you.