A group of researchers from Korea University in Seoul has published details of the development of a stretchable acoustic device. The prototype can function as a loudspeaker, recording device and microphone and the team, led by Professor Ha Jeong Sook, has proven its ability to function after 2,000 stretches. The development has been tipped for future use in the growing wearable electronics market.
The Stretchable Acoustic Device (SAD) uses a liquid metal coil of Galinstan and a Neodymium (Nd) magnet with researchers injecting Galinstan into a micro-patterned elastomer channel.
Demonstrations of the device being operated simultaneously as a loudspeaker and a microphone were carried out and measurements of the frequency response showed that the SAD was mechanically stable under both 50% uniaxial and 30% biaxial strains.
A stress test of 2000 repetitive applications and a 50% uniaxial strain was passed and voice and beeps were recorded and played back while the device was attached to and stretched over a wrist.