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Show HN: Open-Source eInk Bike Computer
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Illustration only Photo by Olya P on Unsplash
An open-source eInk bike computer built on the LilyGO T5S3 ESP32-S3 board supports offline maps via SD card and Bluetooth 5 for cycling sensors, but lacks a barometric altimeter, magnetometer, and waterproofing.
This project provides a fully open-source alternative to commercial cycling computers, allowing builders to modify firmware and use offline maps without proprietary constraints. The documented tradeoffs clarify where hardware limitations, basic GPS, no compass, no altimeter, no waterproofing, restrict practical use compared to sealed commercial units.
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The device uses a LilyGO T5S3 4.7" e-paper panel with ESP32-S3, 16 MB flash, 8 MB PSRAM, and Bluetooth 5 for sensor connectivity.
Offline maps, routes, and ride files are stored on an SD card, and firmware can be installed from a Chromium browser over USB.
Key limitations include no barometric altimeter, basic GPS without multi-band support, no magnetometer for compass orientation, and no waterproofing or IP rating.
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