OpenTrailPaper - DIY e-paper bike computer

Show HN: Open-Source eInk Bike Computer

OpenTrailPaper is an open-source firmware that turns the LilyGO T5S3 4.7" E-Paper PRO into a fully functional bike computer. It displays ride data and offline maps, follows GPX routes, records FIT files, and connects to Bluetooth sensors. The device works independently once maps and routes are loaded, with no account or subscription required. An optional iOS companion app simplifies route planning, map building, and firmware updates. While it's a development project requiring DIY assembly and protection, it offers a customizable and affordable alternative to commercial bike computers.