If you need to detect a very small force, here’s a new option from hacker Andrew Quitmeyer: “Goophene,” or silly putty with graphene embedded in it. As shown in the first video below, it can be combined with a microcontroller to detect changes in resistance when deformed. Because of the structure of silly putty, it not only changes resistance, but heals itself so that it’s ready to sense another force a short time later, even if the structure is significantly changed.
He notes that this substance is so sensitive that he’s even able to use it in with a Teensy 3.2 board to sense finger pokes, heartbeats, breathing, and even light touches with a napkin. Quimeyer has been searching for years for a method to record ant on trees in jungles, and after hearing about a lab-made version of the stuff decided to try it himself. Currently, the substance can only detect medium-sized ants if they are irritated, but he hopes to eventually be able to pick up these critters under normal circumstances.
Another interesting take on this sensing device is shown in the second video seen here, where he actually embeds monofilament fishing wire into a lump of this putty. When touched, the filaments disturb the putty, allowing them to sense the surrounding area like a set of electronic whiskers.