E-Paper Climate Logger (Weathergotchi)

The E-Paper Climate Logger, affectionately known as the “Weathergotchi,” is an open-source project designed to provide a robust and visually clear solution for tracking environmental conditions. This repository serves as a one-stop shop for the project, containing not only the firmware but also the professional-grade PCB schematics and CAD files required to build the physical unit.

At its core, the Weathergotchi is designed to solve the problem of persistent environmental monitoring. By using an e-paper (E-Ink) display, the device ensures that climate data remains visible even without active power to the screen, significantly extending battery life and providing a paper-like reading experience that excels in bright environments.

Hardware Architecture

The project is built around the ESP32-S3 microcontroller, a powerful chip that provides the necessary processing power and wireless capabilities for modern IoT logging. The specific hardware implementation uses a custom board definition referred to as templog-v1.

Key hardware characteristics include:

• Microcontroller: ESP32-S3 with QIO QSPI memory mapping.
• Display: High-contrast E-Paper screen.
• Optimized Memory: The system is configured to run without PSRAM (BOARD_HAS_NO_PSRAM), indicating a lean and efficient firmware design focused on core logging tasks.
• Mechanical Integration: The repository includes full CAD files, allowing users to 3D print or manufacture a custom enclosure that fits the PCB perfectly.

Firmware and Software Design

The firmware is developed using the Arduino framework within the PlatformIO ecosystem. This choice allows for a balance between high-level ease of use and low-level hardware control. The system relies heavily on the GxEPD2 library, which is a specialized driver for E-Ink displays, providing the logic needed to handle partial updates and complex graphical rendering on the e-paper panel.

Technical highlights of the firmware implementation include:

• Error Management: The build is configured with a debug level set to ESP_LOG_ERROR, ensuring that the system remains performant by only processing critical system messages.
• Build System: Utilizes PlatformIO with custom extra scripts (extra_script.py) to handle pre-build processes, ensuring a consistent environment across different development setups.
• Monitoring: Standardized serial communication at 115200 baud via /dev/ttyACM0 for easy debugging and data retrieval during development.

Getting Started

To build the firmware, developers should use PlatformIO. The configuration is pre-set to target the templog-esp-s3 environment. The project manages its own dependencies, specifically requiring the GxEPD2 library (version 1.6.4 or higher). Because the repository includes the full PCB and CAD files, the transition from firmware development to a fully realized hardware product is streamlined for the user.