An Edible Chitosan-Based Acoustic Sensor for Sound-Responsive Actuation in Edible Robots

This study presents an edible acoustic sensor and its application in edible robotics and robotic food as a transducer in acoustic unidirectional communication. The sensor consists of a thin chitosan piezoelectric film sandwiched between two mesh-patterned gold electrodes. The piezoelectric coefficient (d 33) of the device is 3.70 ± 1.52 pC/N, which is comparable to values of other existing biomaterial-based piezoelectric systems. We demonstrated successful near-range communication in air using ON/OFF keying. As a proof-of-concept of the sensor in an edible robot, we developed a system design for interactive gastronomy. The edible robot features movable arms and neck, which are individually actuated via a pneumatic controller in response to high-frequency tones (14, 17, and 20 kHz) detected by the edible sensor. Beyond our culinary experience, the sensor can be used as an edible transducer in acoustic communication systems, including smart packaging, ingestible diagnostics and environmental applications.