rpm sensing with proximity sensor

Projects Discussion and Showcase Robotics
15

dear all,

i've taken all coments and advise into consideration. did some extra reading and came up with the following.

/* Alimoestar S.K.
 *  original code may 2018
 *  16 aug 2018 revised 
 *  coments and advise from arduino forum toopic :rpm sensing with proximity sensor
 * 
  */

const byte interruptPin = 2;
volatile long n=0;
volatile long RPM=0;
volatile boolean flag=0;
long RPMperiod;
unsigned long previoustime=0;


void setup()
{
  Serial.begin(9600);
  attachInterrupt(digitalPinToInterrupt(interruptPin), sensor, FALLING);

}

void loop()
{
    if(flag)
  {
    RPM=(60000000UL/RPMperiod);   //One (1) signal per rotation.
    interrupts();
    Serial.print("RPM = ");
    Serial.println(RPM );
    flag=0;
  }
}

void sensor()
{unsigned long currenttime=micros();
  RPMperiod=float ( currenttime- previoustime);
  flag=1;
  previoustime = currenttime;

}

in the serial monitor i'm seeing my rpm value and a lot of other things.