Nixie Tube Audio Meter

A full writeup is available here.

Directory Structure

• schematics
  • tube-board - the board that powers and controls the nixie tubes
  • tube-offset-1,2 - PCBs that hold the tubes in place
  • audio-board - a teensy-based board that takes in S/PDIF audio over TOSLINK, does DSP, and outputs control data to the tube boards
  • custom - custom kicad parts for this project
  • case - freecad designs and macros for the case, plus some resultant SVGs I used to laser-cut the acrylic
  • bom - a list of some non-commodity part numbers
• code
  • audio-board - the code for the board that reads in S/PDIF audio over TOSLINK, does DSP, and controls the tube boards
  • linux-control - some code for controlling the tube boards from Linux/mac. Mostly used for testing.
  • test - used for testing the DSP code on desktop
  • tube-board - code for the board that powers/controls the bargraph tubes
  • vumeter-lib - hardware-independent code

Building the code

Go into code/audio_board and code/tube_board and run cargo build --release. (Without --release, the binaries may be too large.)

Uploading the code

First, build the code.

Tube board

Go into code/tube_board.

Plug your AVR-ICE or similar JTAG programmer into the tube board via the programming header and run ./program.sh.

Audio Board

Go into code/audio_board.

Plug in your teensy over USB, put it in programming mode, and run ./program.sh

Building the PCBs

Get KiCad and open the schematics. How to export the schematics depends on your choice of PCB manufacturer. They should have instructions available online.