Hi.
I've been playing around with the CapSense library. It works great when I'm touching it. touch touch touch, all day long.
I'm curious if there is a way to sense of there is another person or two touching the person connected to the sensor.
With a 10M ohm resistor and unshielded wire, when I hold someones hand while touching the wire I see a small but not particularly significant change in the values. How could I make this more pronounced? I know that changing the resistor value will give me different sensitivities, but from what I've seen it's a linear change, and the different remains (scale-wise) rather small.
Is there a better circuit/sensing solution I could be looking into?
I think you are always going to be at the mercy of environmental factors changing the readings more than an extra person.
If you can persuade everyone to hold hands in a broken circle, then you could just measure the total resistance of your chain of people and try and derive a number. But again, very dependent on the sweatiness of palms etc.
Do you have an application in mind for this, or is it just an experiment?
There's no question there will be environmental issues (this will be outdoors), but that's sort of ok. Some variance from person to person, group to group is acceptable, as long as it's possible to know when no one is there.
Certainly measuring resistance across people will yield more reliable results, but it looks like there is only one point of contact available.