Use humans as switches / detect contact between human

[ianm2]

Hi,

I'm planning an interactive game, where people have to work together to connect the correct pins by holding their hands. The clue is that there can be multiple pins to be connected. Here is a little sketch – please no comment on my fabulous sketching styles

The green "bulbs" are the connection points. In the example, three "bulbs" have to be connected by four people.

How is that possible? I did some research, this topic helped a lot. But in that case, there are only two pins to be connected.

So, how could I achieve this? I know how to program a Microcontroller, and I have a very basic understanding of electronics … but I actually don't know where to start here. Do you have some ideas, any resources to start with, or any thoughts?

Thank you.

[jremington]

This might give you some ideas: Banana Controller: Building an affordable Custom Controller with the Arduino Uno - DEV Community

Touching a naked Arduino input pin will result in unpredictable HIGH and LOW values, due to static electrical charges present in the environment.

[gilshultz]

Have you considered a low power low frequency modulated AC signal on the blobs. Low frequency to keep it from radiating. You would need to demodulate the signal to determine if there was a connection. Also the level will change as it passes through bodies.

[ianm2]

Hi,

thank you. I found something, which also uses this "level changes" you suggested, i guess? I found this pretty promising. Basically, it is this Setup:

I understand it so far, thanks to the explanation. So this is the status without touch:

So in this case A7 reads HIGH (5V).
If you touch the two points its this status:

Now this circuit works basically as a voltage divider. So A7 reads half or less of the 5V.
The R3 resistor and the capacitor generally just "smooth" out the signal (I guess it's pulling down the signal towards GOUND).

Alright, I haven't tested it yet but it seems really promising. But I can't wrap my head around the fact that I want multiple touchpoints. Imagine a scenario, where there are 6 touchpoints, and sometimes only 3 touchpoints have to be "connected", sometimes 5 touchpoints, etc. Like in the screenshot here, imagine the filled circles are to be touched. As you see, there isn't always a "Ground Pin" like in the example above. How to use the logic from the 2 touchpoint example from above in a scenario like this?

I appreciate any help!