I believe its GND. I can try another one and did with no change
On the multimeter when I read the SIG and GND on the voltage divider this goes between .6V and 1.1 when the laser is aligned and not aligned with the PNP receiver
The values are never going over 300 so unsure how this code will work, upon execution (and I believe mean SensorValue) this yields zero as the condition is not true.
So in essence, whilst I can see the voltage change when testing the voltage dividers signal and gnd pins, i can't seem to reflect this on the Arduino