Soft tactile logic was developed that can make decisions at the material level where the sensor is receiving input, rather than relying on a centralized, semiconductor-based logic system. The resulting device is not quite a robot and not quite a computer but has characteristics of both.

The approach was inspired by the octopus, which has a centralized brain but also has significant neuronal structures throughout its arms. This raises the possibility that the arms can make decisions based on sensory input, without direct instruction from the brain.

At the core of the soft tactile logic prototypes is a common structure: pigments that change color at different temperatures, mixed into a soft, stretchable silicone form. That pigmented silicone contains channels that are filled with metal that is liquid at room temperature, effectively creating a squishy wire nervous system. Pressing or stretching the silicone deforms the liquid metal, which increases its electrical resistance, raising its temperature as current passes through it. The higher temperature triggers color change in the surrounding temperature-sensitive dyes; the overall structure has a tunable means of sensing touch and strain.

The researchers also developed soft tactile logic prototypes in which this same action — deforming the liquid metal by touch — redistributes electrical energy to other parts of the network, causing material to change colors, activate motors, or turn on lights. Touching the silicone in one spot creates a different response than touching in two spots; in this way, the system carries out simple logic in response to touch.

For more information, contact Michael Dickey at This email address is being protected from spambots. You need JavaScript enabled to view it.; 919-513-0273.


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This article first appeared in the June, 2020 issue of Tech Briefs Magazine.

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