Thinking/Creating with Active Materials

Sensors from Ephemeral Material

By combing conductive ink with degradable materials simple touch sensors can be created with unique affordances.

Printing conductive ink on to various substrate materials is an easy means for creating capacitive touch sensors. The sensor need only be wired to an Ardiuno where the capacitance can be evaluated. Simple user interface elements like buttons and sliders can also be quickly produced using this method, along with touch surfaces and even multi-touch and gesture based interfaces.

A capacitive touch sensor was printed with carbon conductive ink (bare ink) onto a banana leaf, with LED’s used to indicate intensity of touch. Curiously the capacitive quality of the leaf changed over time, impacting the behaviour of the sensor. As the leaf dried out, the change in the capacitance reading from the sensor effectively heightened the sensitivity of the sensor, resulting in a proxim- ity sensor rather than a touch sensor.

This unusual behaviour could be easily anthropomorphised; interpreting the plant as having agency in the interaction. Given that the leaf is much more fragile, the behaviour is as though it were resisting touch by responding with an increased sensitivity.