I’ve open-sourced a small offline hiking GPS project built on ESP32-S3:

👉 https://github.com/chengshiwu619/hiking-gps

This is not a fitness tracker or smartwatch clone — it’s a GPX route execution device for hiking.

🎯 What it does

You load a GPX route before hiking, then the device helps you execute it in real terrain.

It focuses on answering:

• Am I still on the route?
• Am I deviating / how far off-route?
• How far to finish / how much ascent remains?
• What terrain comes next (slope / climb pressure)?

No accounts, no cloud, no online maps.

🧠 Design philosophy

• Offline-first (fully usable without phone signal)
• Low-power reflective LCD (ST7305 1-bit display)
• Minimal UI, optimized for “glanceable hiking info”
• Route execution > navigation planning

🔧 Hardware

• ESP32-S3 (16MB Flash / 8MB PSRAM)
• Waveshare 4.2” RLCD (ST7305, monochrome)
• ATGM336H GPS module
• BMP280 barometer (altitude assist)
• EC11 rotary encoder
• SD card (GPX + preprocessed map tiles)

🧩 Software stack

• ESP-IDF + LVGL
• Custom GPX parser + route profiler
• Offline 1-bit map tiles (pre-converted)
• Real GPS tracking with fallback simulation
• Route matching + deviation detection

⚙️ Current status

• Real GPS fix integrated and stable
• GPX route execution pipeline working
• Live metrics: distance / ascent / deviation
• RLCD display pipeline running on real hardware
• EC11 input + UI navigation working

📌 Project focus (important)

This is intentionally not:

• not Garmin / Suunto competitor
• not smartwatch OS
• not online map system
• not fitness/social platform

It’s a single-purpose route execution tool for hiking

If anyone is interested in:

• ESP32-S3 real-time embedded UI systems
• offline navigation / mapping
• low-power LVGL applications
• GPS + GPX processing pipelines

I’m happy to go deeper into architecture or hardware design decisions.