LCD Management

It easy to see word, phrases, data, etc. on a LCD display

I used a 2x16 display.

The ciscuit diagram for connection to a generic display you can find easly online for example in the tutorial of Arduino as follow.

Schema collegamenti

In my case the display is a 1602B

I not know so muth about display, but comparing the connection above with a pattern of display, I don't think you will find difficult to figure out how to connect it. For example the pin D4-D5-D6-D7 in 1602B are corresponding to pins 11-12-13-14, R / W and E respectively 5-6 and so on.

Then the potentiometer adjusts the contrast of the LCD. A simple trimmer 47k or 100k is good for test operation.

There are two connections A and K (anode and cathode) that are used for display backlighting.

From online examples and with some creativity I implemented this:

#include <LiquidCrystal.h>

LiquidCrystal lcd(7, 6, 5, 4, 3, 2); //define LCD pin
int led = 13,i=2;
unsigned long SendTime = 0;
unsigned long S=0;
bool LED=true;

void setup() {
lcd.begin(16, 2);
lcd.print("Hello, World!:-)");
pinMode(led, OUTPUT); //board led blink
lcd.setCursor(0, 1);
lcd.print("T: : :");
}

void blink_led() { //led sub program
if (millis() > SendTime + 1000) {
SendTime = millis();
if (LED==true) {
LED=false;
digitalWrite(led, HIGH);
}
else {
LED=true;
digitalWrite(led, LOW);
}
}
}

void hms() { //convert numerical value time in h m s

//time sub program

unsigned long int t=millis()/1000;
unsigned short int h,m,s;
if (t >= 3600) { //hour print
h=millis()/3600000;
if (h<10) {
lcd.setCursor(3,1);
lcd.print(h);
lcd.setCursor(2,1);
lcd.print("0");
}
else {
lcd.setCursor(2,1);
lcd.print(h);
}
}
else {
h=0;
lcd.setCursor(2,1);
lcd.print("00");
}

if (t >= 60) { //minutes print
m=millis()/60000-h*60;
if (m<10) {
lcd.setCursor(6,1);
lcd.print(m);
lcd.setCursor(5,1);
lcd.print("0");
}
else {
lcd.setCursor(5,1);
lcd.print(m);
}
}
else {
m=0;
lcd.setCursor(5,1);
lcd.print("00");
}

if (t>0) { //second print
s=millis()/1000-m*60-h*3600;
if (s<10) {
lcd.setCursor(9,1);
lcd.print(s);
lcd.setCursor(8,1);
lcd.print("0");
}
else {
lcd.setCursor(8,1);
lcd.print(s);
}
}
else {
s=0;
lcd.setCursor(8,1);
lcd.print("00");
}
}

void point() { //point sub program
if (millis()> S + 249) {
S = millis();
if (i>4) {
i=1;
lcd.setCursor(10+i,1); // lcd.setCursor(17-i,1); reverse point
lcd.print(" ");
}
lcd.setCursor(11+i,1); // lcd.setCursor(16-i,1);
lcd.print(".");
lcd.setCursor(10+i,1); // lcd.setCursor(17-i,1);
lcd.print(" ");
i++;
}
}

void loop() { //main program

point(); //sub program call
blink_led();
hms();

}

From the program comments, you shuld understand how it works.

Now you can make changes to get familiar and have fun with sperimentation.

Some photos of the construction:

Now a short video done long ago before changing the bad connections with the best:

VIDEO