Example of using a single counter and the modulo operator (%) to time multiple events.

SynchronizingCounterAndModulo.ino

/*
 
  Natalie Freed, 10-3-2013
 
  Example of using a single counter and the modulo operator (%) to time multiple events.

  For LWHS Building and Programming Intelligent Machines Fall 2013.
 
  To use, open Serial Monitor to view output.
 
*/

int counter = 0;

void setup()
{
  //start serial port
  Serial.begin(9600);
}

void loop()
{
   Serial.println("This line prints every second."); 
   
   if(counter % 3 == 0) //if counter is divisible by 3 (% is the remainder operator, called "modulo")
   {
     Serial.println("This line prints every 3 seconds.");
   }
   
   if(counter % 5 == 0) //if counter is divisible by 5 (% is the remainder operator, called "modulo")
   {
      Serial.println("This line prints every 5 seconds."); 
   }
   
   delay(1000); //wait 1 second
   counter = counter + 1; //increase counter by 1
}