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Fix MQ303A voltage offset bug

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This commit is contained in:
Miguel Angel Califa Urquiza 2025-06-04 17:46:28 -05:00
parent c927504bf5
commit 92f3c30e82
1 changed files with 6 additions and 2 deletions
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8
src/MQUnifiedsensor.cpp
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@ -142,10 +142,14 @@ float MQUnifiedsensor::validateEcuation(float ratioInput)
float MQUnifiedsensor::readSensor(bool isMQ303A, float correctionFactor, bool injected)
{
//More explained in: https://jayconsystems.com/blog/understanding-a-gas-sensor
float voltageResolution = _VOLT_RESOLUTION;
if(isMQ303A) {
_VOLT_RESOLUTION = _VOLT_RESOLUTION - 0.45; //Calculations for RS using mq303a sensor look wrong #42
// Issue #42: MQ303A requires a 0.45V offset for the RS calculation. The
// previous implementation permanently decreased _VOLT_RESOLUTION every time
// the sensor was read which produced incorrect results after multiple calls.
voltageResolution -= 0.45;
}
_RS_Calc = ((_VOLT_RESOLUTION*_RL)/_sensor_volt)-_RL; //Get value of RS in a gas
_RS_Calc = ((voltageResolution*_RL)/_sensor_volt)-_RL; //Get value of RS in a gas
if(_RS_Calc < 0) _RS_Calc = 0; //No negative values accepted.
if(!injected) _ratio = _RS_Calc / this->_R0; // Get ratio RS_gas/RS_air
_ratio += correctionFactor;