[Leigh] is a HAM operator (you may know him as wa5znu). He is familiar with a signal visualization tool called a waterfall which plots signal strength and frequency over time. He wanted to ...

Since the interrupt signal comes from outside the Arduino it is called as external interrupt. Arduino Uno R3 has two external interrupts: int.0 (pin 2) and int.1 (pin 3). While connecting a RT to ...