Nixie Tube Calculator Clock w/Android Control

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Eric Cohen

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Jul 12, 2016, 8:03:19 PM7/12/16
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Thought y'all might be interested in my conversion of a 1971 Singer/Friden EC1117 nixie tube calculator into an Android controlled date/time clock with arbitrary digit display.  This will probably make more sense after watching a demo of it in operation here:

https://www.youtube.com/watch?v=mibd44goZ-E

If anyone is interested in further details or building their own I've posted more information (including code, schematics and scope traces) at http://epieye.com/nixie/

Have fun!

- Eric

Russell Taylor

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Jul 12, 2016, 8:34:21 PM7/12/16
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Thank you for sharing this - it really is brilliant and has given me some inspiration (now all I need is the skill) 😊


Russell.




From: neoni...@googlegroups.com <neoni...@googlegroups.com> on behalf of Eric Cohen <eric...@gmail.com>
Sent: 13 July 2016 00:03
To: neonixie-l
Subject: [neonixie-l] Nixie Tube Calculator Clock w/Android Control
 
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Eric Cohen

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Jul 13, 2016, 1:12:46 PM7/13/16
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Hi Russell, thanks for the kind words!

Not sure what your background is but you might try starting with a Nixie clock kit.  Just the act of following directions, assembling the kit and getting it to work will get you pretty far.  If you don't feel confident taking that on you can start with even simpler low voltage kits to work on soldering and basic EE skills.

The calculator conversion is actually trickier because it uses the existing display interface, so you first have to understand that to get it working.  It's not just a matter of ripping the guts out and installing an existing nixie clock board.  But with some practice and patience you could probably get there thought!

- Eric


On Tuesday, July 12, 2016 at 5:34:21 PM UTC-7, russell wrote:

Thank you for sharing this - it really is brilliant and has given me some inspiration (now all I need is the skill) 😊


Russell.




From: neoni...@googlegroups.com <neoni...@googlegroups.com> on behalf of Eric Cohen <eric...@gmail.com>
Sent: 13 July 2016 00:03
To: neonixie-l
Subject: [neonixie-l] Nixie Tube Calculator Clock w/Android Control
 
Thought y'all might be interested in my conversion of a 1971 Singer/Friden EC1117 nixie tube calculator into an Android controlled date/time clock with arbitrary digit display.  This will probably make more sense after watching a demo of it in operation here:

https://www.youtube.com/watch?v=mibd44goZ-E

If anyone is interested in further details or building their own I've posted more information (including code, schematics and scope traces) at http://epieye.com/nixie/

Have fun!

- Eric

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Paolo Cravero

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Jul 13, 2016, 1:28:55 PM7/13/16
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Eric that's an excellent work and very inspiring.
I wonder how much time you spent on it!

I have a desk calculator with VFD to repurpose as a clock. I will keep your result in mind when I will be reverse engineering the circuit, in case I can hook it up in a similar way you did. Not knowing how such a calculator works I originally meant to emulate keypresses and increase the displayed time as a simple addition. But now!

My calculator keypad is a matrix of some sort. The uC is a generic 4-bit microcontroller Hitachi HD614080 that drives directly the 12-digit VFD. Reverse engineering ahead.

Let's see what I will come up with. And how long it will take.

Meanwhile I will look at your video few more times.
Paolo




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Eric Cohen

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Jul 13, 2016, 6:39:38 PM7/13/16
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Hi Paolo, thanks for the great feedback!

What type of calculator do you have?  Regardless you might want to look at the PDF slides on my website as I have more details about how the display bus works; it might be helpful even for other types of calculators.

To your point, I'd estimate I spent a total of about 60 hours on this from start to completion, mostly on evenings during the week.  Surprisingly I was able to figure out the bus signaling and protocol pretty quickly; I'd say after about 3 hours of probing with the scope I had a pretty good idea in my head of how it all worked.  I started out with 4504s in DIP packages on breadboards for prototyping; this plus writing the c code and getting to the point where I could drive arbitrary digits probably took another 10 hours.  As is often the case with these projects, the majority of the time was spent with all the little details: things like packaging and board rework, mounting the 4504s, powering the Raspberry Pi, writing the Android app and so on.  I also decided to host my own gitlab server and do some other similar tangential type stuff which took some more time.  Then making the video probably took around 3 hours.

- Eric
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