**EcoThreads: Prototyping Biodegradable E-textiles Through Thread-based Fabrication** **Abstract:** EcoThreads is a sustainable e-textile prototyping approach that fabricates biodegradable functional threads using wet spinning and thread coating methods. The project demonstrates five sample applications, including a braided capacitive touch sensing hair accessory, woven pH-sensing underwear, a woven heat-sensing bento box band, a knitted cooling gel for fever, and a woven sweat rate sensing patch. The wet spinning tool is built from a modified DIY syringe pump, and the conductive and interactive threads can be integrated into textiles through weaving, knitting, embroidery, and braiding. A workshop study with e-textile practitioners showed the compatibility of EcoThreads with existing e-textile prototyping processes, highlighting its potential for individual creators to incorporate biodegradable materials into their practices. **Keywords:** e-textiles, sustainability, bio-design **Introduction:** E-textiles, or smart textiles, integrate conductive and interactive materials into textiles for sensing, actuating, and communication capabilities. While e-textile practices often use common textile crafting techniques, the material choices are often not environmentally friendly. EcoThreads addresses this issue by providing a sustainable life cycle approach for e-textile prototyping, focusing on biodegradable conductive and interactive threads. The project introduces two accessible thread-based fabrication methods: wet spinning and thread coating, which can be used to create conductive and interactive threads suitable for various e-textile applications. **Related Work:** The literature review covers the current state of e-textiles in HCI, sustainable wearable prototyping, and thread-based fabrication and modification techniques. EcoThreads aims to bridge the gap between material science and textile crafts, offering a sustainable solution for e-textile prototyping. **Sustainable E-Textile Life Cycle:** The EcoThreads workflow includes design/planning, fabrication, textile integration, use/wear, and iteration. The design/planning phase involves responsible material sourcing, while the fabrication step includes spinning functional yarns and modifying non-functional materials. The textile integration phase focuses on creating e-textiles by individual creators, and the use/wear phase involves transient use cases. The iteration phase reflects on the learning from the design and materials to inform new iterations. **Fabricating EcoThreads:** The project details two fabrication methods: wet spinning and thread coating. Wet spinning uses a modified DIY syringe pump to extrude conductive and interactive threads, while thread coating involves coating natural fiber yarns with conductive dispersions. The characterization of the material properties, including resistance and tensile strength, is also discussed. **Workshop Study:** A workshop study with five e-textile practitioners demonstrated the compatibility of EcoThreads with existing e-textile practices. Participants successfully incorporated EcoThreads into their specialized crafting techniques, highlighting its ease of use and environmental benefits. The study also revealed the importance of material sourcing and sustainability awareness in e-textile prototyping**EcoThreads: Prototyping Biodegradable E-textiles Through Thread-based Fabrication** **Abstract:** EcoThreads is a sustainable e-textile prototyping approach that fabricates biodegradable functional threads using wet spinning and thread coating methods. The project demonstrates five sample applications, including a braided capacitive touch sensing hair accessory, woven pH-sensing underwear, a woven heat-sensing bento box band, a knitted cooling gel for fever, and a woven sweat rate sensing patch. The wet spinning tool is built from a modified DIY syringe pump, and the conductive and interactive threads can be integrated into textiles through weaving, knitting, embroidery, and braiding. A workshop study with e-textile practitioners showed the compatibility of EcoThreads with existing e-textile prototyping processes, highlighting its potential for individual creators to incorporate biodegradable materials into their practices. **Keywords:** e-textiles, sustainability, bio-design **Introduction:** E-textiles, or smart textiles, integrate conductive and interactive materials into textiles for sensing, actuating, and communication capabilities. While e-textile practices often use common textile crafting techniques, the material choices are often not environmentally friendly. EcoThreads addresses this issue by providing a sustainable life cycle approach for e-textile prototyping, focusing on biodegradable conductive and interactive threads. The project introduces two accessible thread-based fabrication methods: wet spinning and thread coating, which can be used to create conductive and interactive threads suitable for various e-textile applications. **Related Work:** The literature review covers the current state of e-textiles in HCI, sustainable wearable prototyping, and thread-based fabrication and modification techniques. EcoThreads aims to bridge the gap between material science and textile crafts, offering a sustainable solution for e-textile prototyping. **Sustainable E-Textile Life Cycle:** The EcoThreads workflow includes design/planning, fabrication, textile integration, use/wear, and iteration. The design/planning phase involves responsible material sourcing, while the fabrication step includes spinning functional yarns and modifying non-functional materials. The textile integration phase focuses on creating e-textiles by individual creators, and the use/wear phase involves transient use cases. The iteration phase reflects on the learning from the design and materials to inform new iterations. **Fabricating EcoThreads:** The project details two fabrication methods: wet spinning and thread coating. Wet spinning uses a modified DIY syringe pump to extrude conductive and interactive threads, while thread coating involves coating natural fiber yarns with conductive dispersions. The characterization of the material properties, including resistance and tensile strength, is also discussed. **Workshop Study:** A workshop study with five e-textile practitioners demonstrated the compatibility of EcoThreads with existing e-textile practices. Participants successfully incorporated EcoThreads into their specialized crafting techniques, highlighting its ease of use and environmental benefits. The study also revealed the importance of material sourcing and sustainability awareness in e-textile prototyping