void loop()

{

static unsigned long analogSampleTimepoint = millis();

if(millis()-analogSampleTimepoint > 40U)

//every 40 milliseconds,re

ad 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++)

analogBufferTemp[copyIndex]= analogBuffer[copyIndex];

averageVoltage = getMedianNum(analogBufferTemp,SCOUNT) * (float)VREF

/ 1024.0; // read the analog value more stable by the median filtering alg

orithm, and convert to voltage value

float compensationCoefficient=1.0+0.02*(temperature-25.0);

//temp

erature 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*compensatio

nVolatge - 255.86*compensationVolatge*compensationVolatge + 857.39*compens

ationVolatge)*0.5; //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");

}