voltage-to-tds
wayland/total-dissolved-solids/voltage-to-tds
Convert voltage measured by sensor to total dissolved solids (ppm).
voltage-to-tds
@/voltage-to-tds
Convert voltage measured by sensor to total dissolved solids (ppm).
Analognumber
Analog signal from TDS sensor.
V-Refnumber
Reference voltage. For the Arduino Uno/Mega the reference voltage is 5. For ESP32 the reference voltage is 3.3V.
TempCnumber
Temperature in degrees celsius.
TDSnumber
Total dissolved solids (ppm).
C++ implementation
//Based on http://www.cqrobot.wiki/index.php/TDS_(Total_Dissolved_Solids)_Meter_Sensor_SKU:_CQRSENTDS01
#pragma XOD dirtieness disable
node {
void evaluate(Context ctx) {
auto analog = getValue<input_Analog>(ctx);
auto refV = getValue<input_V_Ref>(ctx);
float voltage = analog*refV;
auto tempC = getValue<input_TempC>(ctx);
float compensationCoefficient = 1.0 + 0.02 * (tempC-25.0);
float compensationVoltage = voltage/compensationCoefficient;
Number tds = (133.42 * compensationVoltage * compensationVoltage * compensationVoltage - 255.86 * compensationVoltage * compensationVoltage + 857.39 * compensationVoltage) * 0.5;
emitValue<output_TDS>(ctx, tds);
}
}