Nixie IN-1 Tower Clock

Nixie IN-1 Clock

Nixie IN-1 Clock
Another 6 digit Nixie clock, this time in a vertical tower format.


Design Documents

Schematic Diagram - Controller Boardnixie_tower_schematic.pdf
Schematic Diagram - Backpack BoardNixie Backpack II Schematic.pdf
3D Print
Source Code - Arduino (clock controller)
Source Code - PIC16F1615pic16f1615.asm


Power SupplyRequires 12V 1A DC
Power BulbAlways on
Digit TubesAuto shutoff after 30 minutes of no motion
StatusRed/green power indicator, green indicates GPS lock
Knob TurnTest digits, automatically returns to time display
Knob PressTurn knob to change the UTC to local time offset

Dual IN-1 Backpack
The clock is built using three Dual IN-1 Backpack modules and a main controller board. Each Dual IN-1 Backpack has a microcontroller and the drive circuitry for two IN-1 tubes. The backpack is supplied with +5V, +170V, and controlled via a serial interface. The serial interface is 9600 baud receive only, and all the backpacks are connected in parallel.
Nixie Backpack II Schematic
Code for this design

Each backpack is assigned an ID from A to Z. In this clock the backpacks are designated 'H', 'M', and 'S'. The backpack ID is set by connecting one backpack at a time and issuing the special command ATID=X, where 'X' is the ID (A to Z). The ID is stored permanently in the backpack.

Backpack display commands consist of 3 characters; the ID followed by two digit values. If the ID is lowercase then a fade is performed (a cross fade from the current number to the next). Special ID characters '@' (immediate) and '*' (fade) address all backpacks.
    @--    (blank both digits in all modules instantly)
    H12    (set module 'H' to '12', instant)
    h12    (set module 'H' to '12', with fade)
    H12M34S56    (show "12:34:56" instantly)

Clock Controller Board
The controller PCB has the Arduino Pro Mini and a bunch of connectors to plug in all the modules.
Clock Controller Schematic
Arduino code for the clock

User Interface
The user interface is a rotary encoder with push.

Motion Sensor Module
A small PIR motion sensor activates the clock.
PIR Sensor Module

Time Base Module
A NEO-6M GPS module provides the primary time base. The processor takes over timekeeping during periods when the GPS signal drops out.
Neo-6M GPS Module

High Voltage Power Supply Module
A generic MAX1771 based high voltage module makes 170V for the Nixies. This tiny module makes just enough current, ~20mA for the clock.
High Voltage Module

Build Pictures

Control Board
Dual IN-1 Backpack Module Dual IN-1 Backpack Module

Backpack Interconnect Cable
Dual IN-1 Backpack Module

Dual IN-1 Backpack Module Dual IN-1 Backpack Module Dual IN-1 Backpack Module

Completed Clock
Dual IN-1 Backpack Module Dual IN-1 Backpack Module