I am trying to synchronize some imaging software with subject behavior during an experiment. I currently have an arduino sending 500 ms pulses of HIGH digital output every 5000 ms, and plan on capturing this output in my imaging software to be streamed to file concurrently with the images. Problem is, the data acquisition hardware only accepts analog BNC inputs. So I figure I could run a wire from an I/O to the data acquisition hardware and record it as voltage. Then I can just scale/match up the ~5V pulses with the behavioral data to make sure both datasets are on the same time scale.
If I run a wire from the digital output pin (say, pin 53 on a duo) and attach the wire as the signal/central wire in a BNC connector, do I need to worry about grounding? Novice to electronics, and for whatever reason I can't figure out a clear answer on google.