Nixie IN-1 Tower Clock
Nixie IN-1 Clock
Another 6 digit Nixie clock, this time in a vertical tower format.
Features:
- (6) IN-1 Nixie Tubes with Sockets
- Nixie Lifespan Maximization
- GPS Disciplined Primary Timebase
- Accuracy: ±1 Second
- Automatic Time Setting
- Single Rotary Encoder Interface
- Motion Sensor
- 12V 1A Power
- 3D Printed Enclosure
- Modular Design
Design Documents
| Schematic Diagram - Controller Board | nixie_tower_schematic.pdf |
| Schematic Diagram - Backpack Board | Nixie Backpack II Schematic.pdf |
| 3D Print Files | nixie_tower_mechanical.zip |
| Source Code - Arduino (clock controller) | Arduino.zip |
| Source Code - PIC16F1615 | pic16f1615.asm |
Operation
| Power Supply | Requires 12V 1A DC |
| Power Bulb | Always on |
| Digit Tubes | Auto shutoff after 30 minutes of no motion |
| Status | Red/green power indicator, green indicates GPS lock |
| Knob Turn | Test digits, automatically returns to time display |
| Knob Press | Turn 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.
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.
Examples:
@-- (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.
Arduino code for the clock
User Interface
The user interface is a rotary encoder with push.
- Turn the knob to test the display; it simply turns on all the same digit.
- Press to enter time setting mode, turning the knob adjusts the UTC offset.
Motion Sensor Module
A small PIR motion sensor activates the clock.
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.
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.
Build Pictures
Control Board
Backpack Interconnect Cable
Interior
Completed Clock
