authMicroprocessorsAndPeripherals2019/todoFindCoolNameForProject/todoFindCoolNameForProject.ino

/*
 * TODO: write something here
*/
#include <SevSeg.h>
#include "DHT.h"

// Digital pin connected to the DHT sensor
#define DHTPIN 2
#define DHTTYPE DHT11 // DHT 11
#define BUFFER_SIZE 24
#define LOW_TEMP_LED_PIN 3
#define HIGH_TEMP_LED_PIN 4
#define RELAY_PIN 5
#define LOW_TEMP 28
#define HIGH_TEMP 28

// Initializes DHT sensor.
DHT dht(DHTPIN, DHTTYPE);

int temperatureReadingsCounter;
float temperatures[BUFFER_SIZE];

void setup() {
  Serial.begin(9600);
  Serial.println("Running setup function");

  dht.begin();
  temperatureReadingsCounter = 0;
  pinMode(LOW_TEMP_LED_PIN, OUTPUT);
  pinMode(HIGH_TEMP_LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
}

void loop() {
  float lastTemperature = getNewTemp();

  if (lastTemperature >= HIGH_TEMP) {
    // Turns red led and relay on
    digitalWrite(HIGH_TEMP_LED_PIN, HIGH);
    digitalWrite(RELAY_PIN, HIGH);
    // Turns blue led off
    digitalWrite(LOW_TEMP_LED_PIN, LOW);
  } else if (lastTemperature < LOW_TEMP) {
    // Turns blue led on
    digitalWrite(LOW_TEMP_LED_PIN, HIGH);
    // Turns red led off
    digitalWrite(HIGH_TEMP_LED_PIN, LOW);
    digitalWrite(RELAY_PIN, LOW);
  } else {
    // Turns red led off
    digitalWrite(LOW_TEMP_LED_PIN, LOW);
    // Turns blue led off
    digitalWrite(HIGH_TEMP_LED_PIN, LOW);
    digitalWrite(RELAY_PIN, LOW);
  }

  if (temperatureReadingsCounter == BUFFER_SIZE) {
    float avgTemp = calcAverageTempAndReset(temperatures);
    Serial.println(avgTemp);
    temperatureReadingsCounter = 0;
  }
  // Wait a few seconds between measurements.
  Serial.println(temperatureReadingsCounter);
  delay(1000);
}

float getNewTemp(){
  // Reads temperature as Celsius (the default)
  float t = dht.readTemperature();

  // Checks if the read failed and handles the failure
  if (isnan(t)) {
    Serial.print(F("Failed to read from DHT sensor!"));
    return;
  }

  for (int i = BUFFER_SIZE - 1; i>0; i--) {
    temperatures[i] = temperatures[i-1];
  }
  temperatures[0] = t;
  ++temperatureReadingsCounter;

  Serial.print(F("Temperature: "));
  Serial.print(t);
  Serial.println(F("°C "));

  return t;
}

float calcAverageTempAndReset(float *array) {
  float sum = 0 ;  // sum will be larger than an item, float for safety.
  for (int i = 0; i<BUFFER_SIZE; i++){
    sum += array[i];
  }

  return sum / BUFFER_SIZE ;  // average will be fractional
}