Problems with Arduino2560 interrupts for tachometer

Projects Programming
1

Hello guys!!

I am new with arduino. My objetive is make a simple tachometer with arduino, but I don't be able to to entry in the interrupt. The interrupt occurs with a frequency from 1 Hz up to 130Hz

Here is my code. Someone can give me a little bit of light about it?

#include <avr/interrupt.h>

//Global constants

const int pin_motor=2; //Pin interrupt 0

//Global Variables//

int int1=0;//variable for first interrupt.
int int2=0;//Variable for second interrupt.
int ini=0;//Start variable.
int t1=0;//Time 1 safe
int t2=0;//Time 2 calculated
int long RPM_motor=0;


void setup()
{
  pinMode(pin_motor,INPUT);            //pin config as input.
  attachInterrupt(0,Sensor_lessen,FALLING);  //config interrup (nummer interrupt, function call, mode of interrupt)
  Serial.begin(9600);                // Serial speed config.
  sei();
}

void loop()
{
  unsigned long ms_first_int;
  unsigned long ms_Aktuell=millis(); //millis(),Returns the number of microseconds since the Arduino board began running the current program.
                                    //save this mircos in a variable. Overflow occurs after 50 days.
  if((t1==0)&&(int1==1)&&(int2==0))
  {
    ms_first_int=ms_Aktuell;
    t1=1;
    t2=0;
  }
  if((t1==0)&&(int1==0)&&(int2==1))
  {
    RPM_motor=(1/(ms_Aktuell-ms_first_int))*60;
    t2=1;
    t1=0;
  }
  Serial.println(RPM_motor);
  delay(100);
}

void Sensor_lessen()
{
    if(((int1==0)&&(t2==1))||(ini==0))
  {
    int1=1;
    int2=0;
    ini=1;
  }        
  if((int2==0)&&(t1==1)&&(int1==1))
  {
    int2=1;
    int1=0;
  }
}

Moderator edit: CODE TAGS. AWOL.

2

You could google the use of the "volatile" keyword.

3 
int int1=0;//variable for first interrupt.
int int2=0;//Variable for second interrupt.

You might also want to consider meaningful data names.

4

Ok, thanks.