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Hardware Interrupts | NexaLearn IoT Lab | NexaLearn

Advanced Skills30 دقيقة

Hardware Interrupts

How to detect a button press instantly even if Arduino is busy doing something else.

Lesson Content

In long code (especially those using delay), pressing a button might go unnoticed because Arduino is on the wrong line. An Interrupt is a hardware feature — the moment a button connected to an Interrupt Pin is pressed, Arduino immediately drops everything it's doing, executes a small emergency function (ISR), then returns to what it was doing. Pins 2 and 3 on the Uno support interrupts.

Components Needed

Arduino Unoزر ضغاط

Wiring Notes

Connect the button to pin 2 or 3.

Code Example

volatile bool state = false;
void setup() {
  pinMode(13, OUTPUT);
  pinMode(2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(2), blink, FALLING);
}
void loop() {
  // الأردوينو نائم في دالة delay لا نهاية لها، لكن المقاطعة ستعمل
  delay(10000);
}
void blink() {
  state = !state;
  digitalWrite(13, state);
}

Common Mistakes

Writing a long ISR function or one containing delay() or Serial.print(). The ISR must be lightning-fast (change a variable and exit).

Next Lesson

Dual-Core Programming for ESP32