Trouble with ATTiny85 attachInterrupt.

Hello

Below is my code (debug code) that I am trying to make work with ATTiny85. I am trying to use this sensor (http://www.seeedstudio.com/depot/datasheet/water%20flow%20sensor%20datasheet.pdf)
I was able to detect and work with sensor on an arduino uno.

I use the attachInterrupt function with Arduino using the external interrupt 0 which is available on digital pin 2 of arduino .

attachInterrupt(0,chk, RISING);

Now I am trying to make this sensor work on ATTiny85 but ATtiny does not seem to detect the sensor.
I was thinking that to use the attachInterrupt with Attiny we need to know which pin is the interrupt 0 . In the data sheet for Attiny (http://www.atmel.com/Images/doc2586.pdf) on page 50 it says that INT0 is the External Interrupt Request 0 and from the ATTiny diagram on page 2 it shows that INT0 is PB2 pin, so I attached hall sensor to PB2 but that does not seem to detect the sensor.

I checked that my Arduino and Attiny85 are working fine using the blink code and then modified it.

/*
ATTINY85
Blink
Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain.
*/

int led = PB0;
int led2= PB1;
int Sensor = PB2;
volatile int val;

void chk ()
{
val++;
digitalWrite(led2, HIGH);
}

// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(Sensor,INPUT);
attachInterrupt(0,chk, RISING);
}

// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
sei();
}

Can anyone help with using the interrupt with Attiny85.

Thank you

Which core are you using?