Bubbles are always my childhood dream. I try to make a switch with bubbles, which are two circles holding the bubbles and then people can blow some bubble to connect them. The water mixed with dish soap, hand soap in the bathroom and salt to increase conductibility is extremely conducive to connect the circuits.
I made one version prototype which is not suitable to solider. So the second version I use the paper clip to be the bubble-holding material. It works like an adjustable resistor when the bubble is fading! Though it seems fun, its a messy switch which will cause chaos after trigger it lots of time in front of the desk.
Tested the microcontroller with my bubble switch. The metal part of the circles seems to be covered by dry dish soap and salt that makes it hard to conduct electricity. I think it will be better if I try to clean the surface and expose the metal part of the frames before class so I can keep using my switch!
https://i.imgur.com/xgWebpe.jpg
Good idea! Try cleaning it and report back how well it works!