Evaluation of a Spring-Finger Based, Magnetic Connector Concept for Reliable E-Textile Interconnects

Abstract

Reliable, impermanent connectors are a significant challenge in the development of e-textile devices, needed to increase their modularity, a key factor in their ability to be repaired or recycled. The combination of spring loaded contacts and magnetic fastenings is a promising option, as these components exhibit the small size and mechanical compliance necessary for use in flexible devices. This letter details the evaluation of a five-pin, spring finger connector held in place by two pairs of 1-mm-thick NdFeB button magnets. The connector is subjected to bending and straightening around a 9-cm diameter to analyze its suitability for use in an e-textile device. The results show that with 1.3-mm high springs and a backing with a flexural rigidity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.16\,\, {}\times {}10^{-4}$ </tex-math></inline-formula> Nm2, 100% reliability can be achieved on that test. These results indicate a necessity to use small springs that can easily be flattened. However, their small working range means that they may not be as reliable when connecting to uneven surfaces.