// https://programmersqtcpp.blogspot.com/2022/07/termostato-con-dht22.html
#include <LiquidCrystal.h>
#include "dht.h"
#define DHTPIN 6
dht dht22;
LiquidCrystal lcd(12, 11, 10, 9, 8, 7);
const byte g_relayPin = 13;
int16_t g_temperature;
int16_t g_setpoint;
int16_t g_isteresi = 3 * 10;
uint32_t g_timer2sec;
bool checkThermostate(bool state) {
switch (state) {
case LOW:
if (g_temperature <= g_setpoint - g_isteresi) {
state = HIGH;
}
break;
case HIGH:
if (g_temperature > g_setpoint) {
state = LOW;
}
break;
} // end switch (thermostateState)
return state;
} // end checkThermostate()
void setup()
{
Serial.begin(115200);
lcd.begin(16, 2);
pinMode(g_relayPin, OUTPUT);
} // end void setup()
constexpr char *onoff[] = { "OFF", "ON " };
char temperatureBuffer[7];
// struttura di supporto
struct Setpoint {
uint16_t _old;
uint16_t _new = 1024; // new != old
};
Setpoint mySetpoint;
void loop() {
// Non possiamo leggere il sensore ad intervalli
// di tempo inferiori a 2 secondi.
if (millis() - g_timer2sec >= 2000) {
g_timer2sec = millis();
int chk = dht22.read22(DHTPIN);
if (chk == DHTLIB_OK) {
dtostrf(dht22.temperature, 6, 1, temperatureBuffer);
lcd.setCursor(0, 1);
lcd.print(temperatureBuffer);
// da floart x 10 a int16_t
g_temperature = dht22.temperature * 10;
// chiama la funzione termostato
bool thState = checkThermostate(digitalRead(g_relayPin));
digitalWrite(g_relayPin, thState);
// visualizza ON/OFF sul display
lcd.setCursor(10, 0);
lcd.print(onoff[thState]);
} else {
// qui la gestione degli errori relativi al DHT22
}
}
// usa struttura di supporto
mySetpoint._old = analogRead(A1);
if (mySetpoint._old != mySetpoint._new) {
mySetpoint._new = mySetpoint._old;
float stpf = mySetpoint._new / 13.3;
g_setpoint = stpf * 10; // da float x 10 a uint16_t
dtostrf(stpf, 6, 1, temperatureBuffer);
lcd.setCursor(0, 0);
lcd.print(temperatureBuffer);
}
} // end void loop()