Fork of the espurna firmware for `mhsw` switches
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// -----------------------------------------------------------------------------
// NTC Sensor (maps to a NTCSensor)
// Copyright (C) 2019 by Xose Pérez <xose dot perez at gmail dot com>
// -----------------------------------------------------------------------------
#if SENSOR_SUPPORT && NTC_SUPPORT
#pragma once
#include "AnalogSensor.h"
extern "C" {
#include "../libs/fs_math.h"
}
class NTCSensor : public AnalogSensor {
public:
// ---------------------------------------------------------------------
// Public
// ---------------------------------------------------------------------
NTCSensor() {
_count = 1;
_sensor_id = SENSOR_NTC_ID;
}
void setBeta(unsigned long beta) {
if (beta > 0) _beta = beta;
}
void setUpstreamResistor(unsigned long resistance) {
_resistance_up = resistance;
if (_resistance_up > 0) _resistance_down = 0;
}
void setDownstreamResistor(unsigned long resistance) {
_resistance_down = resistance;
if (_resistance_down > 0) _resistance_up = 0;
}
void setR0(unsigned long resistance) {
if (resistance > 0) _R0 = resistance;
}
void setT0(double temperature) {
if (temperature > 0) _T0 = temperature;
}
// ---------------------------------------------------------------------
// ---------------------------------------------------------------------
// Sensor API
// ---------------------------------------------------------------------
// Descriptive name of the sensor
String description() {
return String("NTC @ TOUT");
}
// Descriptive name of the slot # index
String description(unsigned char index) {
return description();
}
// Address of the sensor (it could be the GPIO or I2C address)
String address(unsigned char index) {
return String("0");
}
// Type for slot # index
unsigned char type(unsigned char index) {
if (index == 0) return MAGNITUDE_TEMPERATURE;
return MAGNITUDE_NONE;
}
// Current value for slot # index
double value(unsigned char index) {
double temperature = 0;
if (index == 0) {
// sampled reading
double read = _read();
// Ru = (1023/c - 1) * Rd
double resistance;
double alpha = (1023.0 / read) - 1;
if (_resistance_down > 0) {
resistance = _resistance_down * alpha;
} else if (0 == alpha) {
resistance = _R0;
} else {
resistance = _resistance_up / alpha;
}
// 1/T = 1/T0 + 1/B * ln(R/R0)
temperature = fs_log(resistance / _R0);
temperature = (1.0 / _T0) + (temperature / _beta);
temperature = 1.0 / temperature - 273.15;
}
return temperature;
}
protected:
unsigned long _beta = NTC_BETA;
unsigned long _resistance_up = NTC_R_UP;
unsigned long _resistance_down = NTC_R_DOWN;
unsigned long _R0 = NTC_R0;
double _T0 = NTC_T0;
};
#endif // SENSOR_SUPPORT && NTC_SUPPORT