Why Does My Loop Run Too Fast?

The loop runs as fast as the microcontroller can execute your code. If you want it slower, you must add timing.

The simplest fix

Add a delay:

loop_with_delay.ino

cpp

void loop() {
  // your code
  delay(100);
}

Use millis for non blocking timing:

loop_with_millis.ino

cpp

unsigned long last = 0;
void loop() {
  if (millis() - last >= 100) {
    last = millis();
    // run code
  }
}

Bottom line

Loops are fast by default. Add delay or millis based timing to slow them down.