Using Arduino to Test Your Water Quality

1void setup()
2{
3  Serial.begin(9600);
4}
5
6void loop()
7{
8  int lightIntensity = analogRead(A1);
9  Serial.print("Light Intensity : ");
10  Serial.println(ldr);
11  delay(1000);
12}

1#include <OneWire.h>
2#include <DallasTemperature.h>
3
4#define ONE_WIRE_BUS 9
5
6OneWire oneWire(ONE_WIRE_BUS);
7DallasTemperature sensors(&oneWire);
8
9float Celcius = 0;
10
11void setup()
12
13{
14  Serial.begin(9600);
15  sensors.begin();
16}
17
18void loop()
19{ 
20  sensors.requestTemperatures(); 
21  Celcius=sensors.getTempCByIndex(0);
22  Serial.print(" C ");
23  Serial.print(Celcius);
24  delay(1000);
25}

1/*
2  DFRobot Gravity: Analog TDS Sensor/Meter
3  <https://www.dfrobot.com/wiki/index.php/Gravity:_Analog_TDS_Sensor_/_Meter_For_Arduino_SKU:_SEN0244>
4  
5  This sample code shows how to read the TDS value and calibrate it with the standard buffer solution.
6  707ppm standard buffer solution is recommended.
7  
8  Created 2018-1-3
9  By Jason <jason.ling@dfrobot.com@dfrobot.com>
10  
11  GNU Lesser General Public License.
12  See <http://www.gnu.org/licenses/> for details.
13  All the above must be included in any redistribution.
14*/
15
16#define TdsSensorPin A2
17#define TDS 5.0      // analog reference voltage(Volt) of the ADC
18#define SCOUNT  30           // sum of sample point
19int analogBuffer[SCOUNT];    // store the analog value in the array, read from ADC
20int analogBufferTemp[SCOUNT];
21int analogBufferIndex = 0,copyIndex = 0;
22float averageVoltage = 0,tdsValue = 0,temperature = 25;
23
24void setup()
25{
26  Serial.begin(115200);
27  pinMode(TdsSensorPin,INPUT);
28}
29
30void loop()
31{
32   static unsigned long analogSampleTimepoint = millis();
33   if(millis()-analogSampleTimepoint > 40U)     //every 40 milliseconds,read the analog value from the ADC
34   {
35     analogSampleTimepoint = millis();
36     analogBuffer[analogBufferIndex] = analogRead(TdsSensorPin);    //read the analog value and store into the buffer
37     analogBufferIndex++;
38     if(analogBufferIndex == SCOUNT) 
39         analogBufferIndex = 0;
40   }   
41   static unsigned long printTimepoint = millis();
42   if(millis()-printTimepoint > 800U)
43   {
44      printTimepoint = millis();
45      for(copyIndex=0;copyIndex<SCOUNT;copyIndex++)
46        analogBufferTemp[copyIndex]= analogBuffer[copyIndex];
47      averageVoltage = getMedianNum(analogBufferTemp,SCOUNT) * (float)TDS / 1024.0; // read the analog value more stable by the median filtering algorithm, and convert to voltage value
48      float compensationCoefficient=1.0+0.02*(temperature-25.0);    //temperature compensation formula: fFinalResult(25^C) = fFinalResult(current)/(1.0+0.02*(fTP-25.0));
49      float compensationVolatge=averageVoltage/compensationCoefficient;  //temperature compensation
50      tdsValue=((133.42*compensationVolatge*compensationVolatge*compensationVolatge - 255.86*compensationVolatge*compensationVolatge + 857.39*compensationVolatge)*0.5) - 270 + 90; //convert voltage value to tds value
51      //Serial.print("voltage:");
52      //Serial.print(averageVoltage,2);
53      //Serial.print("V   ");
54      Serial.print("TDS Value:");
55      Serial.print(tdsValue,0);
56      Serial.println("ppm");
57      delay(60000);
58   }
59}
60
61int getMedianNum(int bArray[], int iFilterLen) 
62{
63      int bTab[iFilterLen];
64      for (byte i = 0; i<iFilterLen; i++)
65      bTab[i] = bArray[i];
66      int i, j, bTemp;
67      for (j = 0; j < iFilterLen - 1; j++) 
68      {
69      for (i = 0; i < iFilterLen - j - 1; i++) 
70          {
71        if (bTab[i] > bTab[i + 1]) 
72            {
73        bTemp = bTab[i];
74            bTab[i] = bTab[i + 1];
75        bTab[i + 1] = bTemp;
76         }
77      }
78      }
79      if ((iFilterLen & 1) > 0)
80    bTemp = bTab[(iFilterLen - 1) / 2];
81      else
82    bTemp = (bTab[iFilterLen / 2] + bTab[iFilterLen / 2 - 1]) / 2;
83      return bTemp;
84}