Just use a digital input pin to detect mains hum from your body (assuming you're near mains AC).
Interesting! I am already locked in to this design for the present, but I'm going to do another version in a bit and will give this a try! I had seen some people using this technique, but it seemed like it was a less desirable alternative for some reason. I confess that I'm not an expert in this field (which is why I'm asking these questions lol) so I didn't dive to deeply at the time, but I will try it out.
With regard to my problem above, do you by chance know anything about how to pick a clean power supply? I'm assuming I need a "clean" one but I really don't know. I just see that one power supply produces results I don't like while others don't and I don't know why.