Arduino Based Stopwatch

Over here using Arduino Uno we have implemented stop watch. For this we have used a LCD Keypad shield. This project was implemented by Mr Conor on the Instructables "Arduino Stopwatch". His modified code (modified by Elac) is used as it is as it was perfect.

As LCD Keypad shield is used there is no need for wiring over here it is just a plug and play project.

Components Used

1. Arduino
2. 16x2 Alphanumeric LCD Keypad shield

Select button is used to start the stop watch & the same switch is used to Stop the timer.

Implemented Circuit Output

 

You can download the code HERE 

 #include <SPI.h>  
 #include <LiquidCrystal.h>  
 // these are the pins used on the shield for this sketch  
 LiquidCrystal lcd(8, 13, 9, 4, 5, 6, 7);  
 // variables used on more than 1 function need to be declared here  
 unsigned long start, finished, elapsed;  
 boolean r = false;  
 // Variables for button debounce time  
 long lastButtonPressTime = 0; // the last time the button was pressed  
 long debounceDelay = 50; // the debounce time; keep this as low as possible  
 void setup()  
 {  
 lcd.begin(16, 2); // inicialize the lcd (16 chars, 2 lines)  
 // a little introduction :)  
 lcd.setCursor(4, 0); // set the cursor to first character on line 1 - NOT needed (it sets automatically on lcd.begin()  
 lcd.print("Arduino");  
 lcd.setCursor(3, 1); // set the cursor to 4th character on line 2  
 lcd.print("StopWatch");  
 delay(2000);  
 lcd.clear();  
 lcd.print("Press select for");  
 lcd.setCursor(2, 1); // set the cursor to 3rd character on line 2  
 lcd.print("Start & Stop");  
 }  
 void loop()  
 {  
 CheckStartStop();  
 DisplayResult();  
 }  
 void CheckStartStop()  
 {  
 int x = analogRead (0); // assign 'x' to the Arduino's AnalogueInputs (Shield's buttons)  
 if (x < 800 && x > 600 ) // if the button is SELECT  
 {  
 if ((millis() - lastButtonPressTime) > debounceDelay)  
 {  
 if (r == false)  
 {  
 lcd.clear();  
 lcd.setCursor(3, 0); // needed  
 lcd.print("Time Past");  
 start = millis(); // saves start time to calculate the elapsed time  
 }  
 else if (r == true)  
 {  
 lcd.setCursor(2, 0); // needed  
 lcd.print(" Final Time ");  
 }  
 r = !r;  
 }  
 lastButtonPressTime = millis();  
 }  
 }  
 void DisplayResult()  
 {  
 if (r == true)  
 {  
 finished = millis(); // saves stop time to calculate the elapsed time  
 // declare variables  
 float h, m, s, ms;  
 unsigned long over;  
 // MATH time!!!  
 elapsed = finished - start;  
 h = int(elapsed / 3600000);  
 over = elapsed % 3600000;  
 m = int(over / 60000);  
 over = over % 60000;  
 s = int(over / 1000);  
 ms = over % 1000;  
 // display the results  
 lcd.setCursor(0, 1);  
 lcd.print(h, 0); // display variable 'h' - the 0 after it is the number of algorithms after a comma (ex: lcd.print(h, 2); would print 0,00  
 lcd.print("h "); // and the letter 'h' after it  
 lcd.print(m, 0);  
 lcd.print("m ");  
 lcd.print(s, 0);  
 lcd.print("s ");  
 if (h < 10)  
 {  
 lcd.print(ms, 0);  
 lcd.print("ms ");  
 }  
 }  
 }