Project 01: Divergence Meter

In the anime Steins;Gate, the Divergence Meter is a device designed by Okabe Rintaro to measure how far off the current world is from the ideal Steins Gate worldline. It’s brought back from 2036 by Suzuha, who obtained it from a future verson of Okabe. Okabe consistently uses it as a metric to distinguish how his choices influence the divergence of reality.

The device has become a prominent symbol for the fandom — not surprising, considering the aesthetic of 1950s cold cathode IИ-14 and IИ-16 Nixie tubes. Although the classic appeal draws the attention of many engineers and designers, they can also be dangerous due to the power requirements to drive them: most operating in an excess of 200 volts, requiring a step-up converter, and the life of Nixie Tubes can sometimes reach as low as 5000 hours. Okabe’s design contains some obvious dangers as well, with exposed high-voltage wires and components.

The design I’ve developed puts a twist on the standard divergence meter. Okabe’s Divergence Meter employs the use of IИ-14 Nixie tubes that have a 2 centimeter diameter. I decided to use smaller-diameter IИ-16 tubes so the design would be less cumbersome and could fit a smaller envelope. The design also uses the ESP32 microcontroller to drive the ‘brains’ of the device. To avoid the annoyance of surface-mounting this component to a ground-plane thermal, spending tedious hours with a heat gun blasting at the PCB, I decided to use the Adafruit ESP32-WROOM module as a hat for the custom PCB — connection is made simple with a USB Type A serial connection, so the only requirement is a standard soldering iron. Interfacing with this device is easy. Later in this guide, I’ll explain how to set up Sloeber; it incorporates the Arduino library and interface to compile and flash C++ files to the microcontroller, making the process a lot easier.

Manufacturing is simple as well, no nails or fasteners required— I used wood glue for the entire project. Since I’m out of university and don’t have access to the machine shop, I made this project manufacturable with simple tools: mainly an XACTO saw and knife, drill with standard bits, and sandpaper (aside from the aesthetics, which just requires paint).

This guide will cover each aspect of the design process, with enough information to produce a single Divergence Meter. I assume the person reading this has basic C++ and programming skills. I take no responsibility for the results of others’ interpretations of the design process. Proceed with your own risk!

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