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niektemme/smarttherm_part_sensors.ino Secret

Last active Aug 29, 2015
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Smart Thermostat Arduino - part sensors
//code snippet from: https://github.com/niektemme/smarttherm-arduino/blob/master/arduino-sketch/smarttherm.ino
//ref voltage
#define aref_voltage 3.3
//variables for settemp variable resistor
int sensorPin = 0; //sensor = settemp
int sensorValue = 0;
int sensorOldValue = 0;
//variables for TMP36
int temperaturePin = 1; //act temp
int tempValue = 0;
int tempOldValue = 0;
int tempDisValue = 0;
int tempDisOldValue = 0;
//variables for boiler on off sensor (photo resistor)
int boilerPin = 2;
int boilerValue = 0;
//variables for thermistor
int thermistorPin= 3;
int thermistorValue =0;
int thermistor2Pin= 4;
int thermistor2Value =0;
...
void setup() {
analogReference(EXTERNAL); //analogue refference
...
}
void loop() {
...
float temperature = tempReading(temperaturePin); //getting the voltage reading from the temperature sensor
temperature = (temperature - .5) * 100; //converting from 10 mv per degree wit 500 mV offset
//to degrees ((volatge - 500mV) times 100)
tempValue = (int) (temperature*100);
//reading boiler on of state
float boiler = getVoltage(boilerPin);
boilerValue = (int) (boiler*100);
//avaraging set temperature to .5 degrees celcius
float sensorCalcValue = (round(((analogRead(sensorPin)/5.0)+100.0)/10.0*2.0))/2.0*10.0;
sensorValue = (int) sensorCalcValue;
//Reading thermistor 1 value using thermistorRead() function, sending nominal value and bcofficient (steinhart) to function
float thermistor = thermistorRead(thermistorPin,10000,10000,25,3950);
thermistorValue = (int) (thermistor*100);
//Reading thermistor 2 value using thermistorRead() function, sending nominal value and bcofficient (steinhart) to function
float thermistor2 = thermistorRead(thermistor2Pin,100000,100000,25,4261);
thermistor2Value = (int) (thermistor2*100);
...
}
//function to get analoge value to digital range
float getVoltage(int pin){
return (analogRead(pin) * .004882814); //converting from a 0 to 1023 digital range
// to 0 to 5 volts (each 1 reading equals ~ 5 millivolts
}
//tmp36 sensor fucntion
float tempReading(int pin){
int tempRead = analogRead(pin);
float voltage = tempRead * aref_voltage;
voltage /= 1024.0;
return voltage;
}
//function for read thermistor value given nominal value and bcofficient (steinhart)
float thermistorRead(int pin, int seriesr, int thermistnominal,int tempnom, int bcof) {
float tempRead = analogRead(pin);
// convert the value to resistance
tempRead = 1023 / tempRead - 1;
tempRead = seriesr / tempRead;
float steinhart;
steinhart = tempRead / thermistnominal; // (R/Ro)
steinhart = log(steinhart); // ln(R/Ro)
steinhart /= bcof; // 1/B * ln(R/Ro)
steinhart += 1.0 / (tempnom + 273.15); // + (1/To)
steinhart = 1.0 / steinhart; // Invert
steinhart -= 273.15; // convert to C
return steinhart;
}
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