Create CQRobotTDS.h

bbn_m5atomS3_lite_TDS_CQRSENTDS01/CQRobotTDS.h

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+#ifndef CQROBOT_H
+#define CQROBOT_H
+
+#define CQROBOT_SCOUNT  30
+
+class CQRobotTDS {
+  public:
+    CQRobotTDS(int pin = G39, float aref = 3.3, float adcRange = 4096.0);
+    ~CQRobotTDS();
+
+    float update();  // read and calculate
+    float update(float temp);  // read and calculate
+    void setTemperature(float temp);  // set the temperature and execute temperature compensation
+    void setAdcRange(float range);    // 1024 for 10bit ADC; 4096 for 12bit ADC
+    float getTdsValue();
+
+  private:
+    int pin;
+    float aref;  // default 3.3V on ESP32
+    float adcRange;
+    float temperature;
+
+    float tdsValue;
+    int analogBuffer[CQROBOT_SCOUNT];    // store the analog value in the array, read from ADC
+    int analogBufferTemp[CQROBOT_SCOUNT];
+    int analogBufferIndex = 0;
+    int copyIndex = 0;
+    float averageVoltage = 0;
+
+    int getMedianNum(int bArray[], int iFilterLen);
+};
+
+CQRobotTDS::CQRobotTDS(int pin, float aref, float adcRange)
+  : pin(pin), aref(aref), adcRange(adcRange) {
+}
+
+CQRobotTDS::~CQRobotTDS() {
+}
+
+float CQRobotTDS::update(float temp) {
+  // read and calculate
+  setTemperature(temp);
+  return update();
+}
+
+float CQRobotTDS::update() {
+  // read and calculate
+  static unsigned long analogSampleTimepoint = millis();
+  if (millis() - analogSampleTimepoint > 40U) {
+    // every 40 milliseconds, read the analog value from the ADC
+    analogSampleTimepoint = millis();
+    this->analogBuffer[this->analogBufferIndex] = analogRead(this->pin);    // read the analog value and store into the buffer
+    this->analogBufferIndex++;
+    if (this->analogBufferIndex == CQROBOT_SCOUNT) {
+      this->analogBufferIndex = 0;
+    }
+  }
+  static unsigned long printTimepoint = millis();
+  if (millis() - printTimepoint > 800U) {
+    printTimepoint = millis();
+    for (copyIndex = 0; copyIndex < CQROBOT_SCOUNT; copyIndex++) {
+      this->analogBufferTemp[copyIndex] = this->analogBuffer[copyIndex];
+    }
+    averageVoltage = getMedianNum(analogBufferTemp, CQROBOT_SCOUNT) * this->aref / this->adcRange; // read the analog value more stable by the median filtering algorithm, and convert to voltage value
+    float compensationCoefficient = 1.0 + 0.02 * (this->temperature - 25.0); // temperature compensation formula: fFinalResult(25^C) = fFinalResult(current)/(1.0+0.02*(fTP-25.0));
+    float compensationVoltage = averageVoltage / compensationCoefficient; // temperature compensation
+    tdsValue = (133.42 * compensationVoltage * compensationVoltage * compensationVoltage - 255.86 * compensationVoltage * compensationVoltage + 857.39 * compensationVoltage) * 0.5; //convert voltage value to tds value
+  }
+  return tdsValue;
+}
+
+void CQRobotTDS::setTemperature(float temp) {
+  // set the temperature and execute temperature compensation
+  this->temperature = temp;
+}
+
+void CQRobotTDS::setAdcRange(float range) {
+  // 1024 for 10bit ADC; 4096 for 12bit ADC
+  this->adcRange = range;
+}
+
+float CQRobotTDS::getTdsValue() {
+  return tdsValue;
+}
+
+int CQRobotTDS::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;
+}
+
+#endif