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Homemade Nixie Clock 2x3 Mux
Here is my own private little Nixie Tube Collection


Staircase box with 6 ZM1172 Nixie tubes, From Right - From Left
Better view of the wood, with power off, From Right - From Left - Front View
This Nixie Clock as a kit for sale From Claus Urbach Using proffesional made double sided PCB cards


Inside the box, cutting and soldering all the wires takes some time,
The inside size is so small, it is not possible to fit the powersupply, so this need to be external.

This Nixie Clock is a 2 x 3 Multiplexed version using a PIC16F876 and two 74141 open collector hight voltage drivers.
Two Digits are powered on at the same time, So the Mux only shifts 3 times, to update all 6 digits.
Display update speed is 600 times a sec. for all 6 digits so this is really a no-flicker display.
Download Schematic file:2x3e.pdf NEW UPDATED
Current draw from the +5 Volt powersupply is: 26mA in total (PIC=1.5mA 74141=12mA)
The brightness of the Nixie tubes has 4 levels made in software:
Voltage and total current from the Anode powersupply is:
170V 1.5mA brightnes level 1
165V 2.6mA brightnes level 2
160V 3.6mA brightnes level 3
154V 4.7mA brightnes level 4
Measurements was made using: 4k7 anode resistors,
a 4k7 in series with the hightvolt transformer and 56k resistor as min load parallel with hight voltage DC output.
The Nixie anode resistors should be adjusted to fit the type of tubes used.
In brightness level 4 the 6 digit clock will shift digits using PWM fading, it looks super cool,
Click here to download a 600kb MPEG video of the fading display mode

It is possible to use only 4 digits if wanted, using the same hardware and software,
you need to select this opperation mode once via the two buttons, now the PIC will change the mux type to 2 x 2 mode.
That means Two Digits are powered on at the same time, So the Mux shift 2 times, to update all 4 digits.
you need to select this opperation mode once via the two buttons, now the PIC will change the display type to 2 x 2 mode.
Download Schematic file:2x2e.pdf NEW UPDATED

A 2 digits version is also possible using the same hardware and software
Then it will be direct driven, non multiplexed
you need to select this opperation mode once via the two buttons, now the PIC will change the display type to 2 x 1 mode.
Download Schematic file:2x1e.pdf NEW UPDATED

Believe it or not, it is also possible to use 4 dual anode Nixie tubes, using the same hardware and software,
you need to select this opperation mode once via the two buttons, now the PIC will change the display type to 4 x 1 mode.
Download Schematic file:1x4-2a-e.pdf NEW UPDATED


The homemade single layer PCB card. seen from solder side See component placement


Like you can see on the components placement picture, there needs to be soldered 3 small wires on the bottom side.


The PCB mounted with components

The 2 x 3 mux is an idea by Chris, thanks.
The wooden box for this clock was handmade in Germany by Lothar and Claus, Thank you so much !
The original box design idea, was made by Chris, thanks.
All schematics and PCB and software is made by me, Thomas Scherrer OZ2CPU


The Mahogany case was sanded and varnished 2 times before the 6 Nixie tubes was mounted using glue


The inside looks great, there is no need for screws, the lid fits perfectly.

The connections from the controller part to the Nixie tubes
is made with wires, so that all nixie types (single anode and also dual anode) can be used.
If series producton is wanted, it is simple and easy to make a Nixie PCB
that connects all Nixie tubes to the Controller PCB, so that assembly can be done fast.
My PCB for 6 ZM1000 Tubes: See Layout - PCB and Tubes - PCB Bottom side - Working Clock
My PCB for 4 ZM1030 Tubes: See Layout - PCB and Tubes - PCB Bottom side - Working Clock
My PCB for 6 ZM1040 Tubes: See Layout

The Powersupply part, need a high and a low AC voltage input.
The low input is 8 to 15 volts AC
The high input is 130 to 170 volts AC
I have designed a special made Nixie transformator that can drive ALL kinds of Nixie projects,
from the smallest to the biggest tubes you can find !


The proffecional made PCB version 1.04, the powersupply and the clock board
This PCB and parts was sold via www.nixieclocks.de from 2003 to 2004.
in 2005 a brand new PCB and new super software will be released..

About the Software version 5.4 (1/6 2003) used in this clock.

((A much more advanced version with even DCF77 decoder is available, go to nixieclocks.de to learn more))
This good old version 5.4 has autodectect for 1 Hz, 50 Hz and 60 Hz. input frequency
The input for 1 Hz must be on the same pin as given in the schematics. It can be a GPS signal or any other 1 Hz signal. 50 Hz and 60 Hz are still taken from the mains frequency.
Fading is disabled if clock uses the 1 Hz input mode.
This version has automatic 1/50/60Hz mains frequency selection.
At powerup it blinks the version 3 times in HR (54) then it flips the digits fast for exactly 1 sec to show counting the mains frequency. Then it shows the software version in HR and mains frequency in MIN for about 5 sec. Then it goes to normal clock mode. Time it now pre set to 00:00:00 if in 24 hr mode, else 12:00:00 in 12 hr mode. The mains frequency it has measured will not be displayed in the 2 digit mode.

12-24 hour selection Hold UP/DIM button for 2-3 sec to change from 12 hr to 24 hr mode or back. The EPROM will keep the setting for 12 or 24 hours.

No leading zero If you want to blank the leading zero, then just cut the connection to the first hr "zero sign".

External outputs PIN4 and PIN5 of the PIC16F876 are now outputs to drive blinking colons with. There are 0,5Hz and 1 Hz outputs, so you can choose the blinking speed you prefer. You need to add one more npn transistor like Q4 and a neon bulb. If you prefer an LED led just connect a 470 ohm resistor to pin 4 or pin 5. It is all up to you.

Dimming The UP/DIM button changes the 4 dim levels when clock is in normal RUN-MODE.

Setting the clock The UP/DIM button adds 1 to the highlighted hours or minutes, when in SET MODE. The SET/RUN mode button enters SET MODE when pressed first time, secs are reset and blanked during set mode. HOURS lights up, MINUTES are dimmed for easy indication that it is HOURS that are adjusted now. One more click on the SET/RUN button, changes to MINUTES, now HOURS are dimmed. When pressing SET/RUN the last time, the clock will start in normal run-mode.

The Mode settings To change operating mode hold down SET, then power up. WHILE you still hold down SET, now press DIM until right mode is working, to store this and continue, simply release SET.
To make it easy to see when right mode is chosen the digits will display the tube number as in the schematics:
1-2 is two tube non muxed mode
1-2-3-4 is four tubes 2x2 mode
1-2-3-4 is four tubes 1x4 dual anode mode
1-2-3-4-5-6 is six tubes 2x3 mode
If you use the wrong mode the clock’s display will just not look right, but no harm can be done to tubes or electronics. Simply try again until it looks right

Made in Aug/Sep/Okt 2002. OZ2CPU
(Thanks to Claus for moral support and good ideas)


More about Nixie
http://groups.yahoo.com/group/NEONIXIE-L/
This Best Nixie Clock kit for sale Claus Urbach


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