For this project, I designed and built a roomy, glanceable dashboard for the LilyGo T5 4.7″ E-Paper board (ESP32 + EPD47). The goal was to create a low-power, always-available status display that pulls live telemetry from a MeshStatic device, persists historical data across reboots, and renders it in a clean and minimal interface.

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Motivation

Mesh networks are powerful, but they’re often difficult to monitor at a glance. I wanted a solution that could run passively, without needing a laptop or phone app, while still being readable in bright light and power efficient enough for long-term deployment.

The LilyGo T5 4.7″ board was a perfect fit:

• Large 960×540 grayscale E-Ink panel
• On-board ESP32 with PSRAM
• Good community support and an open driver library

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Features

• Realtime telemetry via HTTP JSON
  Polls a configurable endpoint (default: http://192.168.0.160/json/report) to display system, radio, memory, and power stats.
• Historical data persistence
  Uses SPIFFS as a ring buffer to log ~4 days of samples at 30-minute intervals. Data survives reboots and is displayed as mini-graphs.
• Two historical graphs
  • Channel Utilization % (0–100)
  • Wi-Fi RSSI (auto-scaling)
• Optimized for E-Paper
  Careful use of margins and header fills avoids the common “black line” artifacts at the top row of the EPD47. Layout emphasizes clarity and spacing for at-a-glance reading.

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Technical Implementation

• Board: LilyGo T5 4.7” E-Paper (ESP32, PSRAM, grayscale 4-bpp)
• Core stack: ESP32 Arduino Core (2.0.15+)
• Libraries:
  • LilyGo-EPD47 driver (epd_driver.h)
  • ArduinoJson v7+
  • WiFi / HTTPClient / FS / SPIFFS (ESP32 core)
• File handling:
  On first boot, SPIFFS is formatted automatically and a fixed-size history file (/hist.dat) is created. Samples are appended as a circular buffer for durability.
• Update interval:
  Default is every 30 minutes, adjustable with: static const uint32_t REFRESH_MS = 30UL * 60UL * 1000UL;
• History capacity: static const uint16_t HIST_CAP = 192; // ≈ 4 days @ 30 min

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Screens & Layout

The dashboard is structured with:

• Top Header Bar (system info, reboot counter)
• System & Memory Panels
• Radio / Power / Wi-Fi Panels
• Graphs (Channel Utilization, Wi-Fi RSSI)

The design makes generous use of whitespace, gutters, and section spacing for readability. Fonts are OpenSans bold variants (8–24pt), included as headers for consistency across toolchains.

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Challenges Solved

• E-Paper quirks: Mitigated the infamous top scanline rendering bug by offsetting header rendering away from row 0.
• Efficient persistence: Implemented a fixed-size ring buffer in SPIFFS to avoid wear and corruption, ensuring smooth historical graphing.
• Auto-scaling metrics: Wi-Fi RSSI values are dynamically scaled, keeping the graph informative regardless of signal range.

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Roadmap

Future improvements I’d like to explore:

• Optional battery % graph alongside utilization and RSSI
• On-device settings menu for changing refresh intervals or toggling graphs
• Support for partial refreshes to reduce redraw time and ghosting
• Exporting historical data as CSV or PNG over Wi-Fi for deeper analysis

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Outcome

This project demonstrates my ability to:

• Work directly with embedded hardware (ESP32 + E-Ink)
• Integrate network APIs (JSON over HTTP)
• Implement data persistence on constrained systems (SPIFFS ring buffer)
• Design user-centric UIs optimized for clarity on a unique medium

You can explore the source code and documentation on GitHub:
👉 ESP32 E-Paper MeshStatic Dashboard