Round Display

This is a small PC telemetry monitor built with a XIAO ESP32-S3 and a Seeed 240×240 GC9A01 LCD.

It displays PC stats over USB, gets weather and settings from an Android companion app via BLE, and grabs room temperature, humidity, and pressure from a separate ESP32 sensor node over ESP-NOW.

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Interface

Clock	PC Telemetry	Room Data
Weather	Settings	Mobile Companion

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Architecture

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Features

• LVGL UI designed for the circular screen
• Touch input and brightness control via the CST816D controller
• 3D printed housing
• Linux daemon that uses nvidia-smi to push CPU/GPU stats over USB serial
• React Native Android app (uses native BLE for settings, background weather sync, and status checks)
• PCF8563 RTC keeps time when disconnected
• Battery voltage monitoring via ADC divider
• Wireless room sensor: A separate ESP32 reads temp/humidity/pressure from a DHT11 and BME280, broadcasts via ESP-NOW, then drops into a 120-second deep sleep.

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Repository Structure

├── firmware/
│   ├── data/              # Display assets and fonts
│   ├── src/
│   │   ├── display/       # Main display firmware (PlatformIO)
│   │   └── sensor/        # ESP32 room sensor (PlatformIO)
│   └── platformio.ini
│
├── desktop/               # .NET 9 Linux telemetry service
├── mobile/                # Expo / React Native Android app
│
└── HARDWARE_GUIDE.md      # Pinouts and assembly quirks

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Bill of Materials

Main Display:

• Seeed Studio XIAO ESP32-S3
• Seeed Studio Round Display for XIAO
• 3D Printed Case

Room Sensor Node:

• Any standard ESP32 board (NodeMCU, WROOM, etc.)
• DHT11 sensor
• BME280 sensor

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Getting Started

Firmware (PlatformIO)

Build and upload the main display firmware:

cd firmware
pio run -e display -t upload

For the room sensor node:

pio run -e sensor -t upload

(Check platformio.ini if you need to change your upload ports).

Desktop Service

You need Linux, the .NET 9 SDK, and nvidia-smi.

cd desktop
dotnet restore
dotnet run

The daemon pings the display over serial (115200 baud) and pushes stats every second. You can set it up as a systemd service to run in the background.

Mobile App

You can't use Expo Go because of the native BLE modules. Build and run it locally:

cd mobile
npm install
npm run android

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Hardware Notes

Check HARDWARE_GUIDE.md before putting this together.

A few major quirks to watch out for:

• I2C init order is annoying. The display has to be initialized before I2C, and the CST816D touch controller needs a manual reset sequence.
• There's a 2-bit DIP switch on the back of the Seeed board. It must be flipped ON, or the RTC, touch, and battery monitor won't work at all.

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Status & Roadmap

Most of the main features are done:

• Basic UI and LVGL navigation
• PC telemetry over USB
• Android BLE connection and background weather sync
• Room sensor ESP-NOW integration
• Add more screens (e.g., detailed weather forecast)
• Implement settings sync from the phone

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License

MIT License