Arduino Uno Stopwatch

Can you share the info? code, sch...

Is this link, the video you say?

Arduino Tutorial | Stopwatch with LCD | with CODE & SCHEMATIC!!! - YouTube

If yes, the LCD seems the typical HD44780 compatible, connected in 4-bit mode,so, not over I2C.

Can you share an image of what you see on LCD?

I suppose you are using a 2lines x 16characters display. If you see the first row dark, and the second clear, you are having a problem with the initialitation, so check the wiring. If you see al the LCD clear, maybe you have a problem with the contrast, so disconnect the potentiometer and try connecting a resistor about 100 ohm between Vo and GND.

But, it is wery important that you give us more detailed information just to help you.

Regards,

Miguel

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RE: Arduino Uno Stopwatch

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#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

int ledPin = 13;                    // LED connected to digital pin 13

int buttonPin = 8;                  // button on pin 2

int value = LOW;                    // previous value of the LED

int buttonState;                    // variable to store button state

int lastButtonState;                // variable to store last button state

int blinking;                       // condition for blinking - timer is timing

int frameRate = 100;                // the frame rate (frames per second) at which the stopwatch runs - Change to suit

long interval = (1000/frameRate);   // blink interval

long previousMillis = 0;            // variable to store last time LED was updated

long startTime ;                    // start time for stop watch

long elapsedTime ;                  // elapsed time for stop watch

int fractional;                     // variable used to store fractional part of Frames

int fractionalSecs;                 // variable used to store fractional part of Seconds

int fractionalMins;                 // variable used to store fractional part of Minutes

int elapsedFrames;                  // elapsed frames for stop watch

int elapsedSeconds;                 // elapsed seconds for stop watch

int elapsedMinutes;                 // elapsed Minutes for stop watch

char buf[10];                       // string buffer for itoa function

void setup()

{

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

  pinMode(ledPin, OUTPUT);         // sets the digital pin as output

  pinMode(buttonPin, INPUT);       // not really necessary, pins default to INPUT anyway

  digitalWrite(buttonPin, HIGH);   // turn on pullup resistors. Wire button so that press shorts pin to ground.

lcd.setCursor(0,0);

  lcd.print("Subscribe at");

  lcd.setCursor(0,1);

  lcd.print("TutorialsArduino");

}

void loop(){

  digitalWrite(ledPin, LOW);            // Initiate LED and Step Pin States

  buttonState = digitalRead(buttonPin); // Check for button press, read the button state and store

// check for a high to low transition if true then found a new button press while clock is not running - start the clock   

   if (buttonState == LOW && lastButtonState == HIGH  &&  blinking == false){

    startTime = millis();                               // store the start time

      blinking = true;                                  // turn on blinking while timing

      delay(10);                                         // short delay to debounce switch

      lastButtonState = buttonState;                    // store buttonState in lastButtonState, to compare next time

   }

// check for a high to low transition if true then found a new button press while clock is running - stop the clock and report

   else if (buttonState == LOW && lastButtonState == HIGH && blinking == true){

   blinking = false;                                    // turn off blinking, all done timing

   lastButtonState = buttonState;                       // store buttonState in lastButtonState, to compare next time

// Routine to report elapsed time           

   elapsedTime =   millis() - startTime;                // store elapsed time

   elapsedMinutes = (elapsedTime / 60000L);

   elapsedSeconds = (elapsedTime / 1000L);              // divide by 1000 to convert to seconds - then cast to an int to print

   elapsedFrames = (elapsedTime / interval);            // divide by 100 to convert to 1/100 of a second - then cast to an int to print

   fractional = (int)(elapsedFrames % frameRate);       // use modulo operator to get fractional part of 100 Seconds

   fractionalSecs = (int)(elapsedSeconds % 60L);        // use modulo operator to get fractional part of 60 Seconds

   fractionalMins = (int)(elapsedMinutes % 60L);        // use modulo operator to get fractional part of 60 Minutes

   lcd.clear();                                         // clear the LDC

if (fractionalMins < 10){                            // pad in leading zeros

      lcd.print("0");                                 // add a zero

      }

    lcd.print(itoa(fractionalMins, buf, 10));       // convert the int to a string and print a fractional part of 60 Minutes to the LCD

      lcd.print(":");                                 //print a colan.

if (fractionalSecs < 10){                            // pad in leading zeros

      lcd.print("0");                                 // add a zero

      }

lcd.print(itoa(fractionalSecs, buf, 10));          // convert the int to a string and print a fractional part of 60 Seconds to the LCD

   lcd.print(":");                                    //print a colan.

if (fractional < 10){                                // pad in leading zeros

      lcd.print("0");                                 // add a zero

      }    

lcd.print(itoa(fractional, buf, 10));              // convert the int to a string and print a fractional part of 25 Frames to the LCD

   }

else{

      lastButtonState = buttonState;                  // store buttonState in lastButtonState, to compare next time

   }

// run commands at the specified time interval

// blink routine - blink the LED while timing

// check to see if it's time to blink the LED; that is, the difference

// between the current time and last time we blinked the LED is larger than

// the interval at which we want to blink the LED.

if ( (millis() - previousMillis > interval) ) {

    if (blinking == true){

       previousMillis = millis();                    // remember the last time we blinked the LED

       digitalWrite(ledPin, HIGH);                   // Pulse the LED for Visual Feedback

       elapsedTime =   millis() - startTime;         // store elapsed time

         elapsedMinutes = (elapsedTime / 60000L);      // divide by 60000 to convert to minutes - then cast to an int to print

         elapsedSeconds = (elapsedTime / 1000L);       // divide by 1000 to convert to seconds - then cast to an int to print

         elapsedFrames = (elapsedTime / interval);     // divide by 40 to convert to 1/25 of a second - then cast to an int to print

         fractional = (int)(elapsedFrames % frameRate);// use modulo operator to get fractional part of 25 Frames

         fractionalSecs = (int)(elapsedSeconds % 60L); // use modulo operator to get fractional part of 60 Seconds

         fractionalMins = (int)(elapsedMinutes % 60L); // use modulo operator to get fractional part of 60 Minutes

         lcd.clear();                                  // clear the LDC

       if (fractionalMins < 10){                     // pad in leading zeros

         lcd.print("0");                             // add a zero

         }

       lcd.print(itoa(fractionalMins, buf, 10));   // convert the int to a string and print a fractional part of 60 Minutes to the LCD

         lcd.print(":");                             //print a colan.

       if (fractionalSecs < 10){                     // pad in leading zeros

         lcd.print("0");                             // add a zero

         }

       lcd.print(itoa(fractionalSecs, buf, 10));   // convert the int to a string and print a fractional part of 60 Seconds to the LCD

         lcd.print(":");                             //print a colan.

       if (fractional < 10){                         // pad in leading zeros

         lcd.print("0");                             // add a zero

         }

          lcd.print(itoa((fractional), buf, 10));  // convert the int to a string and print a fractional part of 25 Frames to the LCD

         }

    else{

          digitalWrite(ledPin, LOW);                 // turn off LED when not blinking

          }

}

}

Many thanks

Sarah

Hi Sarah

The LCD pin assignment statement in your code - LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

is the same as in this basic tuorial  Arduino - LiquidCrystal

However, looking at your circuit diagram, it appears that you haven't connected the appropriate Arduino pins to the LCD.

The tutorial includes a circuit diagram which shows how to connect the LCD correctly.

Hope this helps

Good Luck

Neil

Hi Sarah,

Neil is rigth.

If your hardware is cabled as shown the LCD pin assigmentshuold be like this:

LiquidCrystal lcd(7,8,9,10,11,12);

The most important thing, is that you understand that you are initialitating the LCD in 4-bit mode, and the sentence in your code is LiquidCrystal lcd(rs,e,db4,db5,db6,db7), so you have to do well the pin assigment, in order to make it work properly.

Hope it helps,

Miguel