Live Numbers on the LCD

Part of the Displays and Sensors section of Coddy's Arduino journey. Lesson 8 of 24.

lcd.print() prints numbers too, and a variable or a calculation works as well as text:

lcd.print(millis() / 1000);   // seconds since the board started

To keep a number up to date, print it again in loop(). But every print moves the cursor on, so a second print lands after the first: 0, then 00, then 000. Move the cursor back with lcd.setCursor() before each print, and the new number is written over the old one.

void loop() {
  lcd.setCursor(0, 1);
  lcd.print(millis() / 1000);
  delay(200);
}

The short delay() keeps the screen from being redrawn thousands of times a second for a number that changes once a second.

Challenge

Easy

The top row says Seconds:. Under it, show how many seconds the board has run:

in loop(), move the cursor to the start of the bottom row
print millis() / 1000
wait 200 ms

Press Run and watch it count, then Check.

Try it yourself

#include <LiquidCrystal.h>

// RS, E, D4, D5, D6, D7
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  lcd.begin(16, 2);
  lcd.print("Seconds:");
}

void loop() {
  // show the seconds since the board started on the bottom row
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Displays and Sensors

Practice on your own: Arduino playground