Pulse Sensor

RPM sensor that are on 5v i want on one input on arduino and when it get 2 pulses from input i want it to pulse one signal out . Is it possible ?

Yes. Its possible. Those sensors are called tachometers. Here you go: https://www.ebay.com/itm/254149991912 And as for sending 1 out pulse on every 2 pulses received you could program the logic in the software.

More than possible....

const int RPMSensorInputPin = 2; //only pins 2 and 3 are valid on an UNO; other pins available on other Arduinos
const int outputPin = 13; //pick any pin - use the built-in LED for testing
const unsigned long int pulseWidth = 400; //milliseconds = how long you want your output pulse to stay HIGH
volatile bool makeAPulse = false;


void setup() {
  // put your setup code here, to run once:
  pinMode(RPMSensorInputPin, INPUT_PULLUP);
  pinMode(outputPin, OUTPUT);
  digitalWrite(outputPin, LOW);
  attachInterrupt(digitalPinToInterrupt(RPMSensorInputPin), inputCounter, RISING);
}

void loop() {
  // put your main code here, to run repeatedly:
  static unsigned long lastPulseStartTime;
  
  noInterrupts();   //must pause interrupts while we examine and edit the value of makeAPulse
  bool localMakeAPulse = makeAPulse;
  makeAPulse = false;
  interrupts();
  
  if(localMakeAPulse) {
    digitalWrite(outputPin, HIGH);
    lastPulseStartTime = millis();
  }

  if(millis() - lastPulseStartTime > pulseWidth) {
    //time to turn the output pulse off
    digitalWrite(outputPin, LOW);
  }
}

void inputCounter() {
  //interrupt service routine, called whenever the pin goes HIGH
  //use a single boolean variable to do the divide-by-2 operation
  static bool pulseCounter = true;
  pulseCounter = !pulseCounter;
  makeAPulse = pulseCounter;
}

This code is a little simple: it can ONLY divide by 2. If you wanted some other factor, like 3 or 2.567 then it would take a bit more work.

You can test this on any Arduino with just a button or switch between pin 2 and GND. But be aware that regular switches have a lot of "bounce" so you won't always see the desired behavior.

An IC like a flip flop would do the job as well. No need for an Arduino.

I vote flip flop as well. They make small ic single which will divide by two