Clock consists of three main modules.
Base module provides power, user interface and connectors for both logic and display modules. This creates base for entire device.
As Base Module can work with many different display types, many of them require dedicated design of Display Module. Interconnector between Display and Base Module provides eight logic lines, +5V power line and high voltage from step-up converter. More details are provided below.
Display Module designed for Open Nixie project contains 4 Nixie tubes, 74141 decoder and anode drivers for every tube.
Logic module is component that provides all of the real time clock functions. It is responsible for time measuring, backup timekeeping if required and driving displays. Module is powered with 5V line, so it is responsible for producing other required voltages.
Logic module layout is compatibile with Wemos D1 module with EPS8266. When Wemos D1 is used clock is capable of obtaining time setting from NTP server. There is also another Logic Module designed with ATMega328 and DS3231 RTC IC with CR1220 battery backup. It provdes very accurate offline timekeeping.
If you'd like to see more details on this project visit its homepage