Compared to the ESP8266, the ESP32C3 provides much better clock accuracy and reliability, thanks to its advanced hardware and improved timekeeping features. If you received a Nixie clock from me, you are eligible for a free hardware upgrade - just contact me!

This firmware features a high refresh rate display with advanced dimming and blending effects, leveraging the ESP32's RMT (Remote Control) peripheral for precise timing and smooth transitions.

Highlights

High Refresh Rate: Achieves smooth digit transitions and flicker-free display using RMT hardware
Dimming & Blending: Configurable dimming and blending for night mode and digit transitions
WiFiManager Configuration: Easily configure all clock options via a web portal
Prometheus Metrics: Exposes runtime and system metrics for monitoring

Configuration Options via WiFiManager

NTP Time Server: Set the network time server for clock synchronization
City: Select your city for timezone presets
Timezone: Manually specify the POSIX timezone string
Display Mode: Choose between time, date, or alternating time/date display
Dimming Duty Cycle: Adjust brightness for night mode
Dimming Start/End: Set hours for automatic dimming
Blending Duration: Control the duration of digit blending transitions
Hour Format: Select 12-hour or 24-hour display

Prometheus Metrics

The firmware exposes the following metrics for monitoring:

nixie_boot_timestamp_seconds: Boot time of the device
nixie_last_ntp_sync_timestamp_seconds: Last successful NTP synchronization
nixie_littlefs_total_bytes: Total LittleFS storage size
nixie_littlefs_used_bytes: Used LittleFS storage
nixie_uptime_seconds: Device uptime
nixie_display_task_iterations_total: Number of display task iterations
nixie_ntp_sync_count_total: Number of NTP sync events
nixie_wifi_manager_process_count_total: Number of WiFiManager process events

Advanced Features

Automatic NTP Sync: Periodically synchronizes time with the configured NTP server
Stale NTP Detection: Blinks all digits and colons if NTP sync is stale
Critical Section Display Updates: Uses FreeRTOS and portMUX for safe, high-speed display updates

Getting Started

Flash the firmware to your ESP32-C3
Connect to the WiFiManager AP (SSID is based on device MAC)
Configure your clock settings via the web portal
Monitor metrics via Prometheus-compatible tools

For more details, see the source code and comments.