/* Matchbox-Sized Digital Timer 
* DigiSpark Attiny85 linked with TM1637 Display Module 
* By T.K.Hareendran 
*/ 
#include "TM1637.h" 
// Frankie Chu’s Library for TM1637 Display 
// Download this library from the GitHub link shown below
// Put it inside the “arduino/libraries” folder
// https://github.com/reeedstudio/libraries/tree/master/DigitalTube //{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; 
//0~9,A,b,C,d,E,F // Functional for display 
// Wires for display 
#define CLK 0 
#define DIO 1 
#define Pulse 2 // Alarm Trigger Output 
int timer_val=1; // Countdown value in minutes 
int timer_seconds=00; // Display seconds 
// Variables used to store individual numbers 
int firstnum=0; 
int secondnum=0; 
int thirdnum=0; 
int fournum=0; 
TM1637 tm1637(CLK,DIO); // Create instance of the Display 
void setup(){ 
   pinMode(Pulse, OUTPUT); 
   digitalWrite(Pulse, LOW); 
   tm1637.init(); // Display Reset 
   tm1637.set(BRIGHT_TYPICAL); // Brightness Level 
   // BRIGHT_DARKEST = 0,BRIGHTEST = 7 BRIGHT_TYPICAL = 2;
   tm1637.point(POINT_ON); // Centre "colons" ON 
   delay(1000); // Delay of 1 second 
} 
void loop() { 
   // Check if timer is elapsed 
   while (timer_val == 0 && timer_seconds == 0) { 
      tm1637.clearDisplay(); // Clear display 
      tm1637.display(0,0); 
      tm1637.display(1,0); 
      tm1637.display(2,0); 
      tm1637.display(3,0); 
      digitalWrite(Pulse, HIGH); // Alarm Trigger ON 
      delay(1000);  // Wait
      tm1637.clearDisplay(); 
      digitalWrite(Pulse, LOW); // Alarm Trigger OFF
      delay(500); // Wait
   } 
   // Breakdown minutes and seconds in individual numbers 
   if (timer_val > 9) { 
      firstnum = timer_val/10%10; 
      secondnum = timer_val%10; 
   } 
   else { 
      secondnum = timer_val; 
   } 
   if (timer_seconds > 9) { 
      thirdnum = timer_seconds/10%10; 
      fournum = timer_seconds%10; 
   } 
   else { 
      thirdnum = 0; 
      fournum = timer_seconds; 
   } 
   // Show countdown on 4 digit 7 segment display 
   tm1637.clearDisplay(); // Clear display 
   if (timer_val > 9) { 
      tm1637.display(0,firstnum); 
   } 
   if (timer_val > 0) { 
      tm1637.display(1,secondnum); 
   } 
   if (timer_seconds > 9 || timer_val > 0) { 
      tm1637.display(2,thirdnum); 
   } 
   tm1637.display(3,fournum); 
   // Decrease seconds 
   timer_seconds=timer_seconds-1; 
   delay(1000); // Delay of 1 second 
   // Decrease timer 
   if (timer_seconds == -1) { 
      timer_val=timer_val-1; 
      timer_seconds=59; 
   } 
}
// END