Firmware considerations

A project log for Nixie Tap

Minimal USB powered Nixie display and IoT button

mladenmladen 10/15/2017 at 19:050 Comments

Nixie Tap will have 4 "slots" for information display. For the time being, these slots are planned:

  1. Time
  2. Date
  3. Bitcoin value
  4. Ethereum value

The user knows which slot is currently displayed by observing the blinking dot position.

You'll notice that 50% of slots are taken by cryptocurrency. Hopefully, 4 digits won't be enough to display the price :)

State diagram looks like this: 

Basically, it should be an interrupt driven program. So, let's dive in:

Prototype features

Final features


Connect to WiFI using hardcoded credentials, get NTP time and store onto RTC

Serve a WiFi Manager-like hotspot, for user entry of WiFi credentials


Wait for RTC interrupt and poll analog input to detect taps


RTC interrupt

RTC fires an interrupt every 1s, this signals the main function to refresh display

Display time

Read time from RTC and refresh display

Display date

Read time from RTC and refresh display

Display bitcoin

Not implemented

Read BTC value from Internet and display value

Display ethereum

Not implemented

Read ETH value from Internet and display value