Nixie clock

Nixie Clock ESP32-C3

A Nixie tube clock project based on the ESP32-C3, using IN14 and IN3 tubes driven by HV5622 high-voltage drivers.

Hardware

• Microcontroller: ESP32-C3
• Nixie tubes: 6 × IN14 and 2 × IN3
• Driver: HV5622 for cathode switching
• Rotary encoder: EC11 for time configuration
• 3.3V regulator: AP63203WU to power the ESP32-C3 and logic components
• PCB design: SMD (Surface-Mount) components

[!WARNING] This project involves high voltage. Follow proper electrical safety procedures!

Current Features

• Nixie tube display control via HV5622
• Rotary encoder input (EC11) for setting the time
• Internal clock management
• Anti–cathode poisoning routine: periodic cycling and cathode management to prevent oxide buildup and extend tube lifespan
• Wi-Fi connectivity with NTP time synchronization
• Web interface for configuration

Future Features

• Web interface for configuration: timezone, brightness, night mode, and display enable/disable

Software

The code is written in C for the ESP32-C3, organized as follows:

software/nixie_clock_esp32_project/
├── components/
│   ├── uart/
│   ├── gpio_driver/
│   ├── display/
│   ├── clock/
│   ├── hv5622/
│   ├── rotary_encoder/
│   └── wifi/
└── main/

Code Quality & Standards

• The firmware is developed in compliance with MISRA C:2012 guidelines to ensure reliability and safety in embedded systems.
• Modular driver-based architecture for maintainability and scalability.

Usage

Wi-Fi Configuration

To connect to the Nixie clock, use the following credentials:

WIFI_SSID     "NixieClock-Setup"
WIFI_PASSWORD "12345678"

Compilation

The project uses ESP-IDF for ESP32-C3. Make sure your ESP32-C3 development environment is properly set up.

cd software/nixie_clock_esp32_project
idf.py build
idf.py flash

Test

Unit testing

In ESP-IDF terminal:

cd software/nixie_clock_esp32_project/test/unit
cmake -S . -B build
cmake --build build --config Release
.\build\Release\native_tests.exe

Integration testing

In ESP-IDF terminal:

cd software/nixie_clock_esp32_project/test/integration
cmake -S . -B build
cmake --build build --config Release
.\build\Release\native_integration_tests.exe

Documentation

The generated documentation for this project is available here.

License

This project is released under the LGPL v3 license. A separate LICENSE file contains the complete text of the license.

Safety

[!WARNING] This project involves high voltage (~170V for Nixie tubes).

• Never touch the circuit while it is powered
• Work carefully and only with proper knowledge of high-voltage electronics