# LilyGO T5S3 E-Paper: A DIY Trail Computer

> A sunlight-readable e-paper board built for cycling navigation comes with impressive features alongside distinct DIY tradeoffs.
- Title: LilyGO T5S3 E-Paper: A DIY Trail Computer · Opentrailpaper
- Summary: A sunlight-readable e-paper board built for cycling navigation comes with impressive features alongside distinct DIY tradeoffs. The LilyGO T5S3 offers a…
- Keywords: e-paper, hardware, cycling, esp32, diy, technology, startups, LilyGO, T5S3, Trail, Computer, Opentrailpaper
- Source: Opentrailpaper — https://opentrailpaper.com
- Read time: 1 min
- Topics: e-paper, hardware, cycling, esp32, diy, technology, startups
## Readable e-paper built for trails
The LilyGO T5S3 pairs a sunlight-readable 4.7-inch e-paper display with an ESP32-S3 microcontroller, integrated USB-C, and browser-based firmware flashing.

> A 4.7" e-paper panel that is readable in direct sunlight
## Sensor connectivity and offline maps
Bluetooth 5 links directly to external heart-rate, power, and cadence sensors. An onboard SD card slot stores offline map tiles and ride logs.

> Bluetooth 5 for heart-rate, power and cadence sensors
## Basic navigation with missing sensors
Standard GPS can struggle under dense tree cover. Because the board lacks a built-in magnetometer, map screens can only orient while you are actively moving.

> Without a compass the map can only orient from your direction of travel
## Estimated climbing and eight-hour runtime
Without a barometric altimeter, total ascent is calculated from map elevation data. A 1,500 mAh battery powers the device for around 7.4 hours without the front light.

> A 1,500 mAh build ran for roughly 7.4 usable hours with the front light off.
## Touch controls require custom protection
Capacitive touch controls are difficult to operate in rain or while wearing thick gloves. The unsealed bare board requires a custom weatherproof enclosure before riding.

> The board ships bare with no seal or IP rating
## Key takeaway

The LilyGO T5S3 offers a highly readable, open-source bike computer base, but requires custom weatherproofing and relies on estimated elevation.