Hi legends,

I'm working on a project that runs a stopwatch based on the below conditions

• Inputs
  • Day start pushbutton: To start the program
  • Reset pushbutton: To reset the stopwatch counting
  • 0 – 10v Analog input: To start/pause the stopwatch
  • RFID: To authorize the Day start & Reset
• Outputs
  • Max7219: to drive four common cathode 7 segment for hours and minutes.

The targeted scenario:

• The operator will scan the RFID and within 5 seconds will press the Day start pushbutton to start the program.
• The stopwatch will be waiting for the analog input to be less than 10 to start counting.
• If the value of the analog input is greater than 10, the counting will pause.
• To reset the count, the operator must scan again the RFID and within 5 seconds will press Reset push button.

I have finished pretty much most of the work, but I need help with the last point to reset the count.

 

Have you considered the accuracy of the time base? it's not designed for timekeeping.

 

Have you considered the accuracy of the time base? it's not designed for timekeeping.

It will be day by day

 

Wecome to AAC.

Is this a school project?

 

Wecome to AAC.

Is this a school project?

Thanks
No, it's not a school project.

 

I did some modifications here and the code now seems to work fine, except I have to keep the card on the reader all the time.
Any suggestions?



#include <SPI.h>
#include <MFRC522.h>
#include "DigitLedDisplay.h"
#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
#define bt_start_day A4
#define bt_reset A5
#define DIN 5
#define CS 6
#define CLK 7
DigitLedDisplay ld = DigitLedDisplay(DIN, CS, CLK);
bool stopwatch = false;
bool reset = false;
void writevalue(int, int, int);
int hh=0, mm=0, ss=0, ms=0;
int start_stop = 0;
bool timerStart = false;
const int sec_led = 4;
//int sec_led = 0;
void setup() {
Serial.begin(9600); // Initiate a serial communication
SPI.begin(); // Initiate SPI bus
mfrc522.PCD_Init(); // Initiate MFRC522
/* Set the brightness min:1, max:15 */
ld.setBright(14);
/* Set the digit count */
ld.setDigitLimit(4);
pinMode(sec_led, OUTPUT);
pinMode(bt_start_day, INPUT_PULLUP);
pinMode(bt_reset, INPUT_PULLUP);
if(ss<10){ld.write(2, B01111110);}
if(mm<10){ld.write(5, B01111110);}
if(hh<10){ld.write(8, B01111110);}
noInterrupts(); // disable all interrupts
TCCR1A = 0; // set entire TCCR1A register to 0 //set timer1 interrupt at 1kHz // 1 ms
TCCR1B = 0; // same for TCCR1B
TCNT1 = 0; // set timer count for 1khz increments
OCR1A = 1999; // = (16*10^6) / (1000*8) - 1
//had to use 16 bit timer1 for this bc 1999>255, but could switch to timers 0 or 2 with larger prescaler
// turn on CTC mode
TCCR1B |= (1 << WGM12); // Set CS11 bit for 8 prescaler
TCCR1B |= (1 << CS11); // enable timer compare interrupt
TIMSK1 |= (1 << OCIE1A);
interrupts(); // enable
}
//==========================================================================
void loop()
{
// Look for new cards
if ( ! mfrc522.PICC_IsNewCardPresent())
{
return;
}
// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial())
{
return;
}
String content= "";
byte letter;
for (byte i = 0; i < mfrc522.uid.size; i++)
{
content.concat(String(mfrc522.uid.uidByte < 0x10 ? " 0" : " "));
content.concat(String(mfrc522.uid.uidByte, HEX));
}
content.toUpperCase();
if (content.substring(1) == "93 27 0F 1F" || content.substring(1) == "63 7B C9 1B") //change here the UID of the card/cards that you want to give access
{
if(digitalRead(bt_start_day) == 0) stopwatch = true;
if(digitalRead(bt_reset) == 0) reset = true;
else reset = false;
}



//==========================================================================

start_stop = analogRead(A0);
Serial.println(start_stop);
if (start_stop < 10 && stopwatch == true) timerStart = true;
else timerStart = false; // Stop stopwatch
//==========================================================================
if(reset == true){
ms=0, ss=0, mm=0, hh=0; // Reset stopwatch
ld.write(2, B01111110);
ld.write(4, B01111110);
delay(100);
}
ld.printDigit(hh, 2);
ld.printDigit(mm, 0);
if ( (ss % 2) == 0) {digitalWrite(sec_led, 1);}
else digitalWrite(sec_led, 0);

if(timerStart == true){

if(mm<10){ld.write(2, B01111110);}
if(hh<10){ld.write(4, B01111110);}
}
}


//=======================================================================

ISR(TIMER1_COMPA_vect){
if(timerStart == true){ms=ms+1;
if(ms>999){ms=0;ss=ss+1;
if(ss>59){ss=0; mm=mm+1;}
if(mm>59){mm=0; hh=hh+1;}
}
}
}