Page 178 - MDP2020-2

| 인천전자마이스터고등학교 ·············································································································
172

나. tds 센서

#define TdsSensorPin A1
#define VREF 5.0
#define SCOUNT 30

int analogBuffer[SCOUNT];
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)
{

analogSampleTimepoint = millis();
analogBuffer[analogBufferIndex] = analogRead(TdsSensorPin);
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;

float compensationCoefficient=1.0+0.02*(temperature-25.0);
float compensationVolatge=averageVoltage/compensationCoefficient;
tdsValue=(133.42*compensationVolatge*compensationVolatge*compensationVolatge
- 255.86*compensationVolatge*compensationVolatge +
857.39*compensationVolatge)*0.5;