水質檢測、總固體溶解量 TDS sensor
使用Gravity TDS Meter V1.0
影響水質有很多因素,TDS ( Total Dissolved Solids)-水中所溶解的固體也可能是其中之一,溶解的物質變成離子而影響導電度,因此這個感測器計算大約的溶解量。
影響水質有很多因素,TDS ( Total Dissolved Solids)-水中所溶解的固體也可能是其中之一,溶解的物質變成離子而影響導電度,因此這個感測器計算大約的溶解量。
但這個感測器並不能知道所溶解的物體成分為何?也不能真的代表水質好不好?僅能作為影響水質的部分因素。
但這個感測器並不能知道所溶解的物體成分為何?也不能真的代表水質好不好?僅能作為影響水質的部分因素。
[材料]
[材料]
1. Arduino UNO主板 x 1
2. Gravity TDS Meter V1.0感測器 x 1
[Gravity TDS Meter V1.0 感測器 腳位]
[Gravity TDS Meter V1.0 感測器 腳位]
A to arduino A01
+ to arduino 3V3或5V
- to arduino GND
程式碼引用自:https://wiki.dfrobot.com/Gravity__Analog_TDS_Sensor___Meter_For_Arduino_SKU__SEN0244
/***************************************************
DFRobot Gravity: Analog TDS Sensor / Meter For Arduino
<https://www.dfrobot.com/wiki/index.php/Gravity:_Analog_TDS_Sensor_/_Meter_For_Arduino_SKU:_SEN0244>
Created 2017-8-22
By Jason <jason.ling@dfrobot.com@dfrobot.com>
GNU Lesser General Public License.
See <http://www.gnu.org/licenses/> for details.
All above must be included in any redistribution
/***********Notice and Trouble shooting***************
1. This code is tested on Arduino Uno and Leonardo with Arduino IDE 1.0.5 r2 and 1.8.2.
2. More details, please click this link: <https://www.dfrobot.com/wiki/index.php/Gravity:_Analog_TDS_Sensor_/_Meter_For_Arduino_SKU:_SEN0244>
****************************************************/
#define TdsSensorPin A1
#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(9600);
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++)
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; //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; i++)
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;
}
測試結果統計:
測試結果統計:
2020/10/16 室內開飲機:2ppm
2020/10/16 台中市南屯區自來水(水龍頭):138ppm