RTC, LCD, DHT Problem in void loop()

Projects General Guidance
1

Hello,

For some reason there is a problem in my void loop section.
I try to display the day, month, clock, date, temp and humidity.
that all worked fine in the past but now wen i wanna change the time to the new
time i get allot of characters flickering over the lcd.
And every second the time is barley visible.

The things that are connected are:

A 20x4 blue LCD on SCL, SDA
A DHT Sensor on pin 2
A RTC DS3231 on SCL, SDA

Can someone help me please.

This is my code:

#include <Wire.h>
#include <DS3231.h>
#include <LiquidCrystal_I2C.h>
#include "DHT.h"

DS3231 rtc(SDA, SCL); //SDA, SCL
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);

#define DHTPIN 2
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);


byte newCharHorizontal[] = {
        B00000,
        B11111,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000
};

byte newCharVerticalLeft[] = {
        B01000,
        B01000,
        B01000,
        B01000,
        B01000,
        B01000,
        B01000,
        B01000
};

byte newCharVerticalRight[] = {
        B00010,
        B00010,
        B00010,
        B00010,
        B00010,
        B00010,
        B00010,
        B00010
};

byte newCharLeftCorner[] = {
        B01000,
        B11000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000
};

byte newCharRightCorner[] = {
        B00010,
        B00011,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000
};

byte newCharLogoTop[] = {
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B11111,
        B00000
};

byte newCharLogoBottom[] = {
        B00000,
        B11111,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000
};

byte newCharLogoBottomLeftCorner[] = {
        B00010,
        B00011,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000
};

byte newCharLogoBottomRightCorner[] = {
        B01000,
        B11000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000
};

byte newCharLogoTopLeftCorner[] = {
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00011,
        B00010
};

byte newCharLogoTopRightCorner[] = {
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B00000,
        B11000,
        B01000
};

byte newCharLogoVerticalLeft[] = {
        B01000,
        B01000,
        B01000,
        B01000,
        B01000,
        B01000,
        B01000,
        B01000
};

byte newCharLogoVerticalRight[] = {
        B00010,
        B00010,
        B00010,
        B00010,
        B00010,
        B00010,
        B00010,
        B00010
};

byte newCharDegreesCelcius[] = {
        B01000,
        B10100,
        B01000,
        B00011,
        B00100,
        B00100,
        B00011,
        B00000
};

byte newCharBlock[] = {
        B11111,
        B11111,
        B11111,
        B11111,
        B11111,
        B11111,
        B11111,
        B11111
};

void setup() {
 dht.begin();
 rtc.begin();
 //rtc.setTime(18, 53, 00);
 //rtc.setDate(16, 02, 2020);
 lcd.begin(20,4);
 lcd.createChar(5, newCharLogoTop);
 lcd.createChar(6, newCharLogoBottom);
 lcd.createChar(7, newCharLogoBottomLeftCorner);
 lcd.createChar(8, newCharLogoBottomRightCorner);
 lcd.createChar(9, newCharLogoTopLeftCorner);
 lcd.createChar(10, newCharLogoTopRightCorner);
 lcd.createChar(11, newCharLogoVerticalLeft);
 lcd.createChar(12, newCharLogoVerticalRight);

 // Top Lines
 lcd.setCursor(3,0);
 lcd.write(byte(5));
 lcd.setCursor(4,0);
 lcd.write(byte(5));
 lcd.setCursor(5,0);
 lcd.write(byte(5));
 lcd.setCursor(6,0);
 lcd.write(byte(5));
 lcd.setCursor(7,0);
 lcd.write(byte(5));
 lcd.setCursor(8,0);
 lcd.write(byte(5));
 lcd.setCursor(9,0);
 lcd.write(byte(5));
 lcd.setCursor(10,0);
 lcd.write(byte(5));
 lcd.setCursor(11,0);
 lcd.write(byte(5));
 lcd.setCursor(12,0);
 lcd.write(byte(5));
 lcd.setCursor(13,0);
 lcd.write(byte(5));
 lcd.setCursor(14,0);
 lcd.write(byte(5));
 lcd.setCursor(15,0);
 lcd.write(byte(5));
 lcd.setCursor(16,0);
 lcd.write(byte(5));

 // Bottom Lines
 lcd.setCursor(3,3);
 lcd.write(byte(6));
 lcd.setCursor(4,3);
 lcd.write(byte(6));
 lcd.setCursor(5,3);
 lcd.write(byte(6));
 lcd.setCursor(6,3);
 lcd.write(byte(6));
 lcd.setCursor(7,3);
 lcd.write(byte(6));
 lcd.setCursor(8,3);
 lcd.write(byte(6));
 lcd.setCursor(9,3);
 lcd.write(byte(6));
 lcd.setCursor(10,3);
 lcd.write(byte(6));
 lcd.setCursor(11,3);
 lcd.write(byte(6));
 lcd.setCursor(12,3);
 lcd.write(byte(6));
 lcd.setCursor(13,3);
 lcd.write(byte(6));
 lcd.setCursor(14,3);
 lcd.write(byte(6));
 lcd.setCursor(15,3);
 lcd.write(byte(6));
 lcd.setCursor(16,3);
 lcd.write(byte(6));

 // Corners
 lcd.setCursor(2,0);
 lcd.write(byte(9));
 lcd.setCursor(2,3);
 lcd.write(byte(7));
 lcd.setCursor(17,0);
 lcd.write(byte(10));
 lcd.setCursor(17,3);
 lcd.write(byte(8));

 // Vertical Lines
 lcd.setCursor(2,1);
 lcd.write(byte(12));
 lcd.setCursor(2,2);
 lcd.write(byte(12));
 lcd.setCursor(17,1);
 lcd.write(byte(11));
 lcd.setCursor(17,2);
 lcd.write(byte(11));

 
 lcd.setCursor(5,1);
 lcd.print("DV Servers");
 lcd.setCursor(3,2);
 lcd.print("Danny Verhaert");

 delay(5000);
 lcd.clear();
 
}

void loop() {
 lcd.createChar(0, newCharHorizontal);
 lcd.createChar(1, newCharVerticalLeft);
 lcd.createChar(2, newCharLeftCorner);
 lcd.createChar(3, newCharRightCorner);
 lcd.createChar(4, newCharVerticalRight);
 lcd.createChar(13, newCharDegreesCelcius);
 lcd.createChar(14, newCharBlock);

 // Left Corner
 lcd.setCursor(3,0);
 lcd.write(byte(1));

 lcd.setCursor(0,1);
 lcd.write(byte(0));

 lcd.setCursor(1,1);
 lcd.write(byte(0));

 lcd.setCursor(2,1);
 lcd.write(byte(0));

 lcd.setCursor(3,1);
 lcd.write(byte(2));

 // Right Corner
 lcd.setCursor(16,0);
 lcd.write(byte(4));

 lcd.setCursor(16,1);
 lcd.write(byte(3));

 lcd.setCursor(18,1);
 lcd.write(byte(0));

 lcd.setCursor(19,1);
 lcd.write(byte(0));

 lcd.setCursor(17,1);
 lcd.write(byte(0));


 float h = dht.readHumidity();
 float t = dht.readTemperature();

  if (isnan(h) || isnan(t)) {

    lcd.setCursor(0,3);
    lcd.println(F("N/A"));
    return;
    
  }

 float hic = dht.computeHeatIndex(t, h, false);
 lcd.setCursor(14,3);
 lcd.print(h);
 lcd.print("%");
 
 lcd.setCursor(0,0);
 lcd.print(rtc.getDOWStr(FORMAT_SHORT ));
 
 lcd.setCursor(17,0);
 lcd.print(rtc.getMonthStr(FORMAT_SHORT));
 
 lcd.setCursor(6,1);
 lcd.print(rtc.getDateStr(FORMAT_SHORT, FORMAT_LITTLEENDIAN, '/'));

 lcd.setCursor(6,2);
 lcd.print(rtc.getTimeStr());
 
 lcd.setCursor(0,3);
 lcd.print(t);
 //lcd.print(rtc.getTemp() - 2);
 lcd.write(byte(13)); //
}

Thank you in advance.
Danny

IMG_1922 (1).JPG
IMG_1922 (1).JPG3024×2268 1.08 MB

2

Most likely You made some little mistake in the last change of the code. Flickering LCD is easily caused by sending characters at too high rate.
As I see loop() is running at really full speed. Can You try and update the display some 2 - 5 times per second? No human eye will properly read changes made at 10 Hz or more.

3

I would recommend that you create the second set of custom characters at the end of set up, and not each pass through loop.

4

Hello,

First of all thank you for your help and reply.
Second, i'm sorry for the late response but i have been busy with work.

About the problem.
The strangest thing happened.
Because of my time-consuming job i forgot to unplug the device and after a while it stopped showing the random characters on the display.
The characters stood still on the display, so i performed a reset and now it works almost perfect.
Only the day is not shown correct, while the date is correct.

2016×1512 438 KB

I'm using this famous script to set the time on the RTC DS3231.

The message is more then 9000 characters long so i put the file on my website.

Click here to see the RTC SET *.ino file