LCD display Arduino Uno

Question

I am trying to create a basic arduino uno stopwatch displayed on a liquid crystal display. In theory , this is a very easy project, yet I am running into issues with my display. I calculate my minutes and seconds, and then attempt to print them to the display with a colon in between. Coming from java, I presumed a plus was just used. However, this results in a bunch of random, unidentifiable characters flashing on the screen. I tested to see if both seconds and minutes work separate, which they do, so I think it is in the syntax of lcd.print(). I was not able to find this addressed anywhere else. Help would be appreciated.

Code:

#include <LiquidCrystal.h>



LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int seconds;
int minutes;
int timedif;
int starttime = -1;

void setup()
{

    lcd.begin(16, 2); //Initialize the 16x2 LCD


    lcd.clear();    //Clear any old data displayed on the LCD
}

void loop()
{

  lcd.setCursor(0,0);
  lcd.print("Stopwatch");
  lcd.setCursor(0,1);
  if (starttime == -1) { //if running first time, time dif is initiated
    starttime = millis();
  }

  timedif = (millis() - starttime)/1000; //will get difference in terms of seconds

  minutes = floor(timedif/60); // divides by sixty, drops decimal
  seconds = timedif%60; //gets remainder of divided by 60
  lcd.print(minutes + ";" + seconds);

}

Eliad Cohen Eliad Cohen · Accepted Answer · 2018-01-16T19:13:36

What you are printing is a JAVA syntax , and Arduino is using C syntax. See this on how you need to use this API.

You need to build the string (for example as char array) and passed it to the print method

LCD display Arduino Uno

1 Answers