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.
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
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
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
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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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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