# "rising" interrupts behaves as "chance" on mega2560

**URL:** <https://forum.arduino.cc/t/rising-interrupts-behaves-as-chance-on-mega2560/570267>\
**Category:** Sensors\
**Created:** [January 27, 2019, 11:03am UTC](https://forum.arduino.cc/t/rising-interrupts-behaves-as-chance-on-mega2560/570267 "2019-01-27T11:03:45Z")\
**Posts on this page:** 1\
**Showing post:** 13

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**Author:** ![gursoytek](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/gursoytek/32/333655_2.png) [@gursoytek](https://forum.arduino.cc/u/gursoytek)\
**Post date:** [January 27, 2019, 5:26pm UTC](https://forum.arduino.cc/t/rising-interrupts-behaves-as-chance-on-mega2560/570267/13 "2019-01-27T17:26:20Z")

</div>

im already used 5v by 10k pot as voltage divider.  
i tried again  
and plotted interrupt function change according to the pin2 voltage  
two test made

blue: interrupt function  
red : pin2 voltage  
on arduino nano  
[![](https://europe1.discourse-cdn.com/arduino/original/4X/0/7/c/07c6c9b9015e191493e3144bb4117c93be638a3b.png)](https://ibb.co/bzYRyT0)  
if voltage goes up the interrupt called only one times(when voltage level reached 2,5v)

blue: interrupt function  
red : pin2 voltage  
on arduino mega  
[![](https://europe1.discourse-cdn.com/arduino/original/4X/5/0/8/508d0269a7b6c6a0a78db0781767e91520aded37.png)](https://ibb.co/MGQjmbT)  
if voltage between 2,3v to 2,5v interrupt goes looping and blue line high

codes

```cpp
unsigned long delays=0;
int sayi=0, voltage=0,durum2=0;
bool durum=false;
void setup() {
 // pinMode(2 ,INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(2), say, RISING);

  Serial.begin(9600);
}
void say() { sayi++; durum=true;}

void loop() {

if ((millis()-delays)>=50)
{    
delays=millis();

  // Serial.print("durum=");

 if (durum)
 { 
  durum=false; 
  durum2=5000;
    Serial.print(durum2);
  Serial.print(" ");
  }
  else{
    durum2=1000;
      Serial.print(durum2);
  Serial.print(" ");}
  voltage=analogRead(A0);
  voltage=map(voltage,0,1023,0,5000);
  Serial.println(voltage);
}
}

```

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