On the UNO the ext interrupt pins are 2 and 3 pins 0 and 1 are used by serial. Your serial output (prints) may be interfering with our interrupt!. Look in the ref section of this site.
Mark
On the UNO the ext interrupt pins are 2 and 3 pins 0 and 1 are used by serial. Your serial output (prints) may be interfering with our interrupt!. Look in the ref section of this site.
Mark