Rapid Prototyping of Laser-Induced Graphene Sensors With Open-Source Silicon: Paving the Way for Low-Cost and Robust Flexible Wearable Sensing

The open source hardware movement has made significant progress over the past few years. Increasingly, more individuals are engaging with and participating in the open source chip design community, not only to design their chips with available open source tools but also to have their designs physically fabricated and returned to them for practical use. Companies like Google have sponsored physical chip fabrication runs over the past few years, such as OpenMPW, through semiconductor CMOS processes provided by Skywater (SKY130) and GlobalFoundries (GF180) [1]. When we consider the availability of open source chip design tools, a supportive community, reliable fabrication partners, financial sponsors, and a growing infrastructure of suppliers and educators, it becomes clear that a revolution in chip design is an inevitable outcome. By leveraging existing resources provided by the open source community, this article presents the joint development of a new laser-induced graphene (LIG)-based sensor platform. The effort includes the design, fabrication, and testing of an AFE ASIC using open tools and the design and in-house fabrication of LIG sensors. The article presents the ASIC’s design process and the fabricated chip’s testing results. It demonstrates testing a wearable strain gauge LIG sensor and a temperature-sensitive LIG sensor using our AFE chip. The demonstration serves as an example of the potential to develop the sensing system into a multimodal flexible sensing platform.