Delay and Millis together

Projects Programming
1

My code has 7sec delays while valves open before the fans start.

Im trying to use millis to have fans start for 30sec every 6 hours.

Problem is delay and millis dont seem to mix, How do i keep the 7 sec delay and not effect the milis timiing?

#include <DS3232RTC.h>

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#define DHTPIN 11  // what pin we're connected to

// Uncomment whatever type you're using!
//#define DHTTYPE DHT11  // DHT 11
#define DHTTYPE DHT22  // DHT 22 (AM2302)
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
// Initialize DHT sensor for normal 16mhz Arduino
DHT dht(DHTPIN, DHTTYPE);
//DHT dht(DHTPIN, DHTTYPE, 30);
int humidfan = 2;          //  Intake fan for Humid box
int humidv = 3;            //  Valve for humud intake
int freshfan = 4;          // fresh fan
int freshv = 5;            //  fresh valve, air from outside
int exfan = 6;             // exhaust fan
int exv = 7;               // exhaust valve
int dryfan = 8;            // intake fan for dry box
int dryv = 9;              // dry box valve
const int buttonPin = 10;  // button to reset cycle
// DHT pin 11
int DHTpower = 12;  // constant 5v to DHT11
int fridge = 13;    // relay to fridge 240v

int buttonState = 0;  // variable for reading the pushbutton

float lowDry, highDry;
float lowCure, highCure;
//bool cycle;

unsigned long startMillis;  //some global variables available anywhere in the program
unsigned long currentMillis;
const unsigned long period = 30000;  //the value is a number of milliseconds

LiquidCrystal_I2C lcd(0x27, 20, 4);  // Set the LCD address to 0x27 for a 20x4 display


double dewPoint(double celsius, double humidity) {
  // (1) Saturation Vapor Pressure = ESGG(T)
  double RATIO = 373.15 / (273.15 + celsius);
  double RHS = -7.90298 * (RATIO - 1);
  RHS += 5.02808 * log10(RATIO);
  RHS += -1.3816e-7 * (pow(10, (11.344 * (1 - 1 / RATIO))) - 1);
  RHS += 8.1328e-3 * (pow(10, (-3.49149 * (RATIO - 1))) - 1);
  RHS += log10(1013.246);

  // factor -3 is to adjust units - Vapor Pressure SVP * humidity
  double VP = pow(10, RHS - 3) * humidity;

  // (2) DEWPOINT = F(Vapor Pressure)
  double T = log(VP / 0.61078);  // temp var
  return (241.88 * T) / (17.558 - T);
}

void setup() {
  pinMode(humidfan, OUTPUT);
  pinMode(dryfan, OUTPUT);
  pinMode(fridge, OUTPUT);
  pinMode(humidv, OUTPUT);
  pinMode(dryv, OUTPUT);
  pinMode(exfan, OUTPUT);
  pinMode(exv, OUTPUT);
  pinMode(freshfan, OUTPUT);
  pinMode(freshv, OUTPUT);
  pinMode(DHTpower, OUTPUT);
  pinMode(buttonPin, INPUT);

  digitalWrite(humidfan, LOW);
  digitalWrite(dryfan, LOW);
  digitalWrite(humidv, LOW);
  digitalWrite(dryv, LOW);
  digitalWrite(exfan, LOW);
  digitalWrite(exv, LOW);
  digitalWrite(freshfan, LOW);
  digitalWrite(freshv, LOW);
  digitalWrite(DHTpower, HIGH);
  digitalWrite(fridge, HIGH);
  digitalWrite(buttonPin, HIGH);

  Serial.begin(9600);
  lcd.init();       // Initialize the LCD
  lcd.backlight();  // Turn on the backlight
  lcd.clear();      // Clear the LCD screen
  lcd.setCursor(4, 0);
  lcd.print("The Green");
  lcd.setCursor(5, 1);
  lcd.print("Ninja");
  delay(2000);  // Display the startup message for 2 seconds
  lcd.clear();
  dht.begin();

  startMillis = millis();  //initial start time
  lowCure = 10.5;
  highCure = 11.5;  // aim for 11

  lowDry = 11.5;
  highDry = 12.5;  // aim for 12

  if (buttonState = 1; (digitalRead(buttonPin))) {
    lowCure = lowDry;
    highCure = highDry;
    lcd.setCursor(0, 3);
    lcd.print("Dry Cycle / Storage");
    delay(2000);
  } else {
    lowDry = lowCure;
    highDry = highCure;
    lcd.setCursor(0, 3);
    lcd.print("Cure Cycle       ");
    delay(2000);
  }
}

void loop() {

  currentMillis = millis();

  if (currentMillis - startMillis >= period)
  digitalWrite(exv, HIGH);
  digitalWrite(freshv, HIGH);
  digitalWrite(humidv, LOW);
  digitalWrite(dryv, LOW);
  digitalWrite(fridge, HIGH);
  //lcd.setCursor("0, 2");
  lcd.print("Exhaust fans on");
  digitalWrite(freshfan, HIGH);
  digitalWrite(exv, HIGH);
  delay(30000);
  currentMillis = millis();

  float h = dht.readHumidity();
  // Read temperature as Celsius
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit
  float f = dht.readTemperature(true);
  float currentDew = dewPoint(t, h);  // Dew Point for setting pins high


  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println("Failed to read from DHT sensor!");
    lcd.clear();
    lcd.print("Failed to read");
    lcd.setCursor(0, 1);
    lcd.print("from DHT sensor");
    return;
  }

  // Compute heat index
  // Must send in temp in Fahrenheit!
  float hi = dht.computeHeatIndex(f, h);
  float hiDegC = dht.convertFtoC(hi);


  if (f < 19.5) {
    digitalWrite(fridge, LOW);  // Fridge off when set low
  }

  if (f > 21) {
    digitalWrite(fridge, HIGH);
  }

  if (currentDew > lowDry && (currentDew < highDry)) {  // Level to aim for dew point
    dewPointOk(t, h);
  }
  if (currentDew >= highDry) {  //   High dew point, send to dry box
    dewPointHigh(t, h);
  }
  if (currentDew <= lowDry) {  // Dew point low, send to humid box
    dewPointLow(t, h);
  }
}

void dewPointOk(float t, float h) {
  digitalWrite(humidfan, LOW);
  digitalWrite(humidv, LOW);
  digitalWrite(dryfan, LOW);
  digitalWrite(dryv, LOW);
  digitalWrite(exfan, LOW);
  digitalWrite(exv, LOW);
  digitalWrite(freshfan, LOW);
  digitalWrite(freshv, LOW);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Dew Pnt Ok");
  lcd.setCursor(14, 0);
  lcd.print(dewPoint(t, h));
  lcd.setCursor(19, 0);
  lcd.print("c");

  lcd.setCursor(0, 1);
  lcd.print("Temp");
  lcd.setCursor(14, 1);
  lcd.print(dht.readTemperature());
  lcd.setCursor(19, 1);
  lcd.print("c");

  lcd.setCursor(0, 2);
  lcd.print("Humidity");
  lcd.setCursor(14, 2);
  lcd.print(dht.readHumidity());
  lcd.setCursor(19, 2);
  lcd.print("%");

  lcd.setCursor(0, 3);
  lcd.print("Valves Closed");
}

void dewPointHigh(float t, float h) {
  digitalWrite(humidv, LOW);
  digitalWrite(humidfan, LOW);
  digitalWrite(dryv, HIGH);
  digitalWrite(exv, LOW);
  digitalWrite(exfan, LOW);
  digitalWrite(freshv, LOW);
  digitalWrite(freshfan, LOW);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Dew Pnt High");
  lcd.setCursor(14, 0);
  lcd.print(dewPoint(t, h));
  lcd.setCursor(19, 0);
  lcd.print("c");
  lcd.setCursor(0, 1);
  lcd.print("Temp");
  lcd.setCursor(14, 1);
  lcd.print(dht.readTemperature());
  lcd.setCursor(19, 1);
  lcd.print("c");
  lcd.setCursor(0, 2);
  lcd.print("Humidity");
  lcd.setCursor(14, 2);
  lcd.print(dht.readHumidity());
  lcd.setCursor(19, 2);
  lcd.print("%");
  lcd.setCursor(0, 3);
  lcd.print("Dry Box On");
  delay(7000);
  digitalWrite(dryfan, HIGH);
}

void dewPointLow(float t, float h) {  // humid box on
  digitalWrite(humidv, HIGH);
  digitalWrite(dryv, LOW);
  digitalWrite(exv, LOW);
  digitalWrite(exfan, LOW);
  digitalWrite(freshv, LOW);
  digitalWrite(freshfan, LOW);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Dew Pnt Low");
  lcd.setCursor(14, 0);
  lcd.print(dewPoint(t, h));
  lcd.setCursor(19, 0);
  lcd.print("%");
  lcd.setCursor(0, 1);
  lcd.print("Temp");
  lcd.setCursor(14, 1);
  lcd.print(dht.readTemperature());
  lcd.setCursor(19, 1);
  lcd.print("c");
  lcd.setCursor(0, 2);
  lcd.print("Humidity");
  lcd.setCursor(14, 2);
  lcd.print(dht.readHumidity());
  lcd.setCursor(19, 2);
  lcd.print("%");
  lcd.setCursor(0, 3);
  lcd.print("Humid Box On");
  delay(7000);
  digitalWrite(humidfan, HIGH);
}
2

Don't do it....pretty simple I'd have thought.

3

awesome thanks, that fixed it...

4

You can mix whatever you want.

The sketch and your description are together not enough to understand what you want.

Can you use brackets and simple code ?
Right-click on the code in the Arduino IDE and then select "Format Document".
Then check every bracket, every indent, every space, every comma. Make it look good.

This is a bug:

  if (buttonState = 1; (digitalRead(buttonPin))) {

When turning on all compiler warnings, the compiler does not like that line: "warning: init-statement in selection statements only available with -std=c++1z or -std=gnu++1z".
Use simple code, use more lines if you need to. The function digitalRead() does not return a 1, it returns a HIGH or LOW.

// plain and simple code
buttonState = digitalRead(buttonPin);
if (buttonState == HIGH) {

It is unclear what you want here:

  if (currentMillis - startMillis >= period)
  digitalWrite(exv, HIGH);
  digitalWrite(freshv, HIGH);
  digitalWrite(humidv, LOW);
  ...

Only the first line is part of the if-statement.
You have this:

  if (currentMillis - startMillis >= period)
  {
    digitalWrite(exv, HIGH);
  }

  digitalWrite(freshv, HIGH);
  digitalWrite(humidv, LOW);
  ...

Please show in the sketch how you are going to use 6 hours with millis(). It has to be 6 hours as a unsigned long.

// 6 hours in milliseconds is:
//   1000 for seconds
//   60 for minutes
//   60 for hours
//   6 for 6 hours.
unsigned long sixHours = 1000UL * 60UL * 60UL * 6UL;  // UL means "Unsigned Long"
5

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