Other: Waterproof probe
Package includes:
1 x TDS signal adapter board
1 x Waterproof TDS probe
1 x Analog sensor line
source code:
#define TdsSensorPin A1
#define kValue 1.8 //kValue = value of calibrator TDS / measurement to get TDS
#define VREF 5.0 // analog reference voltage(Volt) of the ADC
#define SCOUNT 30 // sum of sample point
Int analogBuffer[SCOUNT]; // store the analog value in the array, read from ADC
Int analogBufferTemp[SCOUNT];
Int analogBufferIndex = 0, copyIndex = 0;
Float averageVoltage = 0, tdsValue = 0, temperature = 25;
Void setup()
{
  Serial.begin(115200);
  pinMode(TdsSensorPin, INPUT);
}
Void loop()
{
  Static unsigned long analogSampleTimepoint = millis();
  If(millis()-analogSampleTimepoint > 40U) //every 40 milliseconds,read the analog value from the ADC
  {
   analogSampleTimepoint = millis();
   analogBuffer[analogBufferIndex] = analogRead(TdsSensorPin); //read the analog value and store into the buffer
   analogBufferIndex ;
   If(analogBufferIndex == SCOUNT)
     analogBufferIndex = 0;
  }
  Static unsigned long printTimepoint = millis();
  If(millis()-printTimepoint > 800U)
  {
   printTimepoint = millis();
   For(copyIndex=0;copyIndex<scount;copyindex )< span=””></scount;copyindex )<>
    analogBufferTemp[copyIndex]= analogBuffer[copyIndex];
   averageVoltage = getMedianNum(analogBufferTemp,SCOUNT) * (float)VREF / 1024.0; // read the analog value more stable by the median filtering algorithm, and convert to voltage value
   Float compensationCoefficient=1.0 0.02*(temperature-25.0); //temperature compensation formula: fFinalResult(25^C) = fFinalResult(current)/(1.0 0.02*(fTP-25.0));
   Float compensationVolatge=averageVoltage/compensationCoefficient; //temperature compensation
   tdsValue=(133.42*compensationVolatge*compensationVolatge*compensationVolatge – 255.86*compensationVolatge*compensationVolatge 857.39*compensationVolatge)*0.5*kValue; //convert voltage value to tds value
   //Serial.print(“voltage:”);
   //Serial.print(averageVoltage,2);
   //Serial.print(“V “);
   Serial.print(“TDS Value:”);
   Serial.print(tdsValue,0);
   Serial.println(“ppm”);
  }
}
Int getMedianNum(int bArray[], int iFilterLen)
{
   Int bTab[iFilterLen];
   For (byte i = 0; i<ifilterlen; span=””></ifilterlen;>
 bTab[i] = bArray[i];
   Int i, j, bTemp;
   For (j = 0; j < iFilterLen – 1; j )
   {
 For (i = 0; i < iFilterLen – j – 1; i )
     {
  If (bTab[i] > bTab[i 1])
      {
bTemp = bTab[i];
    bTab[i] = bTab[i 1];
bTab[i 1] = bTemp;
  }
 }
   }
   If ((iFilterLen & 1) > 0)
bTemp = bTab[(iFilterLen – 1) / 2];
   Else
bTemp = (bTab[iFilterLen / 2] bTab[iFilterLen / 2 – 1]) / 2;
   Return bTemp;
}
​
Connection Photo for reference
Product Photo
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