I'm currently trying to use an Arduino to measure every time a sensor is triggered. Currently the sensor is connected to a 120VAC relay that resets a clock. My idea had been to measure in between the relay and the clock to determine when the sensor was activated or not. I had a couple of ideas about how to do this.
My first idea had been to step down the voltage and connect it to an input pin. Easiest way I can see to do this would be one of these
My other idea had been to try to measure the current running across the wire to determine if the sensor was triggered. My thought had been to try using this
Would either of these methods be suitable or is there an easier way that I'm missing?