This document is a presentation by 李祐棠 on building a nixie tube clock, highlighting challenges related to sourcing components, high voltage circuits, and custom PCB design. It details solutions for controlling the nixie tubes including recommended ICs, microcontrollers, and PCB design tools. The presentation also provides links to resources for further information and open-source code related to the project.

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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