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拿到一块带GPS、LoRa和电子纸的ESP32-S3开发板，大多数人第一反应是拿它做个天气站或者电子书电纸书。
OpenTrailPaper偏偏往硬骨头上啃：把LILYGO T5 E-Paper S3 Pro直接改造成一台能脱离手机运行的骑行码表，离线画地图、跟着GPX路线走、把每一圈记录写成FIT文件，还要接心率带和功率计。
功率、速度、心率、踏频、骑行时间和里程一屏表明
Github地址：
https://github.com/RaemondBW/OpenTrailPaper
T5 E-Paper S3 Pro的核心是ESP32-S3-WROOM-1模组，芯片型号ESP32-S3N16R8，双核LX7最高240MHz，配8MB PSRAM和16MB SPI Flash。显示屏是4.7英寸电子纸，960×540、16级灰阶，叠了一层GT911电容触摸，驱动IC是ED047TC1。无线部分除了ESP32-S3自带的2.4G Wi-Fi 4和蓝牙5.0，板上还塞了一颗SX1262 LoRa模块，兼容433/868/915MHz三个频段，定位芯片是u-blox MIA-M10Q或者Quectel L76K，固件会自动识别装的是哪一颗。另外还有PCF8563实时时钟、BQ25896充电管理配BQ27220电量计，一颗3.7V 1500mAh电池，官方说法是不开前灯大约能撑八小时以内，作者也标注了这个数字后续可能还会优化，整机尺寸129×69×11mm，比手机也厚不了多少。
ESP32干实时的活，手机干规格和搬运的活
OpenTrailPaper把骑行中需要实时响应的部分——GPS定位、速度和传感器采集、路线导航提示、地图渲染、骑行记录写入SD卡——全部放在ESP32-S3这一端，脱离手机也能跑完整趟骑行。手机端反而是干重活的地方：iOS用SwiftUI写，安卓走Jetpack Compose当下还在Discord邀请制内测，负责搜索目的地、规划路线并把GPX发给设备、生成离线地图瓦片、把设备上录好的骑行记录拉回来复盘，以及修改设置和推送固件更新。这种切法的好处很直接：骑到没有信号的山里，手机app可以直接退出，码表照样按已经加载好的路线和地图继续工作。
地图这块处理得比较讲究，用的是H3六边形网格组织瓦片，生成方式有三条路：在手机app里画框生成、用一段Python脚本在终端跑，或者直接在兼容Web Serial的浏览器里用JS现场生成再借助USB下载到SD卡。上手门槛最低的是直接打开项目官网的设置页面，用浏览器把固件刷进去，再按流程把某个区域的地图瓦片存进SD卡根目录下的/maps/tiles。骑行记录固定落地成FIT文件，和结构化训练用的.erg/.mrc文件放在同一层数据组织里，没有互相搅在一起。
左：浏览器里生成离线地图瓦片；右：转弯提示叠在电子纸地图上的实拍成效
传感器和续航
码表借助蓝牙连接心率带、功率计和踏频传感器，ANT/ANT+的兼容放在了另一个独立仓库esp32-ant里，还在推进中，仓库说明里写得很明白了 ——这块当下不算完工状态。整个项目大量用了AI（Claude）辅助写代码，但作者反复强调是有人盯着、有人测试的，不是甩手扔给模型自动生成。
手机端三个主要界面：规划路线、复盘骑行记录、调整设置与推送固件
方案的边界
作者自己列出的短板挺实在：T5 S3 Pro不防水，雨天骑行建议套个自封袋；没有气压计，爬升数据是从地图瓦片的高程信息估算出来的，不是实测；GPS是单频模块，定位速度和抗干扰能力比不上多频思路；没有磁力计，地图方向完全靠行进方向推算，人一停下来朝向就不准了；机身实体按键偏小，戴冬季手套或者手心出汗时，触摸屏操作也不算顺手。电子纸本身强光下好读、静态画面几乎不耗电，这些限制换来的是骑行时真正看得清数据和地图，这笔账在户外情形下是划算的。
硬件不用自己攒，直接买LILYGO官方的T5 E-Paper S3 Pro整机，国内某宝比较便宜，Amazon上大约90美元，AliExpress上103美元左右；下单时选普通固件版本就够。仓库使用Apache-2.0协议，截至9月7日在GitHub上大约146颗star，还处在快速迭代期。
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When most people get an ESP32-S3 board with GPS and LoRa, they think of a weather station or e-reader. But OpenTrailPaper went for the harder problem: turning the LILYGO T5 E-Paper S3 Pro into a full-fledged, phone-free cycling computer — offline map rendering, GPX route following, FIT file recording, and sensor integration.
GitHub: https://github.com/RaemondBW/OpenTrailPaper
The T5 S3 Pro is built around the ESP32-S3-WROOM-1 module (ESP32-S3N16R8), running at 240 MHz with 8 MB PSRAM and 16 MB Flash. The 4.7″ e-paper display (ED047TC1) supports 960x540 resolution and 16 gray levels, paired with a GT911 capacitive touch panel. For wireless, it has 2.4 GHz Wi-Fi 4, BT 5.0, a SX1262 LoRa module for 433/868/915 MHz, and either a u-blox MIA-M10Q or Quectel L76K for GPS. The clock is synced via PCF8563, and battery management is handled by BQ25896 and BQ27220 — with a 1500 mAh battery promising ~8 hours of use (lights off), which the author notes may improve. The device is compact at 129x69x11 mm.
The system splits roles: ESP32 handles real-time tasks (GPS, sensors, navigation, map rendering, SD logging), while the phone app (SwiftUI on iOS, Jetpack Compose on Android, both in beta) offloads route planning, map tile generation, and data synchronization. This allows the computer to operate fully offline during rides.
Left: Browser-based map tile generation; Right: Turn prompt overlaid on e-paper map
Sensor support includes Bluetooth-connected heart rate monitors, power meters, and cadence sensors, with ANT/ANT+ support planned but not yet complete. The project leverages AI (Claude) for code assistance, though human supervision and testing remain critical.
Phone app screens: route planning, ride analysis, and device settings/firmware update
Limitations acknowledged by the author include lack of waterproofing (suggesting ziplock bags for rain), no barometer (elevation from map data), single-frequency GPS, no magnetometer (direction inferred from velocity), and small/awkward buttons. However, the e-paper’s high sunlight visibility and low power consumption make these tradeoffs worthwhile for outdoor use.
The device can be purchased as a pre-assembled unit from LILYGO (around $90 on Amazon, cheaper in China). As of September 7, the project has ~146 stars on GitHub, under active development with the Apache-2.0 license.
Three main interfaces on the mobile app: route planning, reviewing ride records, and adjusting settings with firmware push.
方案的边界
The author's self-reported weaknesses are quite honest: the T5 S3 Pro is not waterproof, so a resealable bag is recommended for rainy rides; there is no barometer, so elevation data is estimated from map tiles rather than measured; the GPS is a single-frequency module, inferior in speed and anti-interference to multi-frequency approaches; there is no magnetometer, so map orientation relies entirely on travel direction, becoming inaccurate when stationary; and the physical buttons are small, making operation with winter gloves or sweaty hands cumbersome. The E-ink screen is readable in bright light and consumes almost no power for static images, which is more important than these limitations when actually riding.
No need to build the hardware yourself; just buy the LILYGO T5 E-Paper S3 Pro as a complete unit. It's cheaper on Taobao than Amazon ($90) or AliExpress ($103). Select the standard firmware version during checkout. The software repository uses the Apache-2.0 license and had ~146 stars as of September 7th, indicating it is in a rapid development phase.
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