You can build an old-fashioned Nixie tube clock by yourself. In this slide I introduce all the challenges and how I overcome them. I also publish all my design on website easyEDA and Github, you can use the design freely if you want to build your own one.

1. Build Yourself a Nixie Tube Clock
李祐棠 YODALEE <LC85301@GMAIL.COM>
COSCUP 2019
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2. About Me
 Yodalee <lc85301@gmail.com>
 Study EE in college, Microwave in graduate school, now rookie
engineer in Synopsys.
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Github: yodalee Blogger: http://yodalee.blogspot.tw

3. Why I Make This
2011 animation
Steins;Gate
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2018 animation
Steins;Gate 0
The real reason:

4. Nixie Tube
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Nixie Tube LED 7 Segment
Display
Used in 1955 - 1970 1970 - present
Drive voltage 180 V 3 V
Drive current 0.3 - 2.5 mA 10 mA
Others Fragile Robust
Cathode
Anode

5. Nixie Tubes Revival
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https://en.wikipedia.org/wiki/Nixie_tube#/media/File:Nixie_Wozniak.jpg
Nixie Watch Nixie ClockPortal 2

6. Challenges
1. Where to buy it?
2. How to get 180V power?
3. How to control it?
4. How to make custom PCB?
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7. Challenge 1 : Where to Buy It
 Ebay: IN-14 Used: USD 5 / pcs, New: USD 12 / pcs
 Totally new from Dalibor Farny: USD 145 / pcs
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8. Challenges 2: High Voltage Circuit
 DC Boost Converter: from 12V to
180V.
 Make your own or buy one.
 Control chip: MC34063.
 Switch MOS: IRF840
 Inductor: 100uH coil (important!)
 Voltage Divider:
511k / 3.3k + 2k variable
Control range: 120 ~ 193 V
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https://upload.wikimedia.org/wikipedia/commons/4/4a/Boost_circuit_2.png

9. Challenges 2: High Voltage Circuit
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10. Challenges 2: High Voltage Circuit
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 How do you control 180V current
Solution Disadvantage
K155ID1 high voltage driver IC Difficult to buy
TLP521 Photocoupler VCEO = 50V
MPSA42/92 NPN/PNP transistor

11. Challenges 3: Controller
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 RTC: DS1307
 12V to 5V:
78M05
 Decoder:
74HC238,
74CD4514
 Controller:
Atmega328p

12. Challenges 3: Controller
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 In the good old days, we write our bare metal program.
 Nowadays, we have Arduino.
 Write Arduino bootloader to Atmega328p chip.
 https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard
 Configure to use internal 1MHz clock.
 Program with serial TX/RX pin

13. Challenges 4: Custom PCB
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 Layout with EasyEDA: https://easyeda.com
 Fabrication with JetPCB: http://tw.jetpcb.com/
V1.01 Size 26.4 cm x 10.4 cm

14. Challenges 4: Custom PCB
 Software Choice: Protel, Altium (proprietary),
EasyEDA, Eagle (need register), Kicad (free)
 EasyEDA advantage:
 Component/Layout are shared, easy to import other’s
component.
 EasyEDA disadvantage:
 Lag when edit a lot of components
 Some function are difficult to use
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15. EasyEDA
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16. EasyEDA
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17. EasyEDA
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18. EasyEDA
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 Signal line width: 0.4mm
 Power line width: 1.0 ~ 1.2 mm

19. EasyEDA
1. Draw schematic
2. Convert to layout
3. Draw layout
4. Place copper layer
Easy right?
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20. Nixie Tube
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 Current limiting resistor: 22K for digit, 75k for dot
 Buy nixie tube base => Difficult to buy. Use single
IC socket as base

21. Programming
 Control DS1307 using Arduino Library
 https://playground.arduino.cc/Code/Time
 Write my own function to read/write 56
bytes NVRam on DS1307 to store
information.
 Do not light up single digit constantly.
Cathode poisoning on other cathode.
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// core code
fun updateTube:
for each tube:
update Tube // 74HC238
update number // 74CD4514
delay(2);

22. v1.02
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V1.02 (photo by HeiHei), shrink size to 26 cm x 8 cm
 Progress so far: it can light up tube.

23. V2.0
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• Split PCB to nixie tube PCB and control PCB
• New high voltage circuit
http://www.nixieclock.org/?p=1454
• Use SMT component.
• Replace DS1307 with DS3231
No schedule right now

24. Open Resource
 Note: https://yodalee.blogspot.com/2018/10/nixie-clock0-
introduction.html
 Source code: https://github.com/yodalee/NixieClock
 V1.01 Schematic and Layout:
https://easyeda.com/lc85301/nixieclock
 V1.02 Schematic and Layout:
https://easyeda.com/lc85301/nixieclock_v1-02
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25. Reference
1. Wikipedia: https://en.wikipedia.org/wiki/Nixie_tube
2. Tube-Tester: http://www.tube-tester.com/
3. 復古咖啡 (Closed)
4. 工作狂人
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26. Thank You for
Listening
EL PSY CONGROO
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