Finished Nixie Watch project (Pictures)

[Craig Smith]

I thought I would post a few pictures of my finished Nixie watch that I have been working on for a while and some pictures of the build.

The finished watch

The breadboard demo setup

After testing lots of different shift registers to control the tubes. I needed a shift register capable of doing the job and that would run at 3v. I went for Micrel MIC5841. Although these are not meant to run at 3v, after lots of testing they would work down to 2.1v very reliably, so operating them at 3v should be fine.

The microprocessor used is a PIC18F13K22
I ended up using an analogue accelerometer (ADXL335) over the i2c one as it drew a lot less current.
To get the 170v required to drive the tubes, I used a DC/DC converter IC (LT1308) and a small transformer 31105R (which I got from David Forbes at Cathode Corner)
To keep the time nice and accurately, I went for a real time clock IC. This is a DS3231M. It has built in temperature correction.
The tubes are NL-5870 (B5870)

The total current drawn when sitting there not displaying is only 96uA


The watch displays the time in a similar way to most of the other Nice watches out there. You tip it to the viewing position and the hours flash, then the minutes. As I wanted the date to shown also, if you keep the watch in the view position, the date will also flash up, day then month.

When the battery gets to 3.5v, the minutes flash twice to show the battery is running low (I copied this idea from David Forbes). When the voltage gets to 3.3v the watch stops displaying.


When testing the circuit I did 45 time reads a day and the watch lasted for 18 days until it stopped displaying the time. It then ran for another week until the battery had dropped to 3v.

PCB's etched by OSHPark

PCB assembled.

I was going to get the watch CNC machined, but it was going to cost a lot of money, so I ended up getting some aluminium laser cut to the rought size and machining it on my mate's lath and milling machine.

I also anodised the case myself in my garage.

I was originally going to use a stainless strap, but opted for a leather one instead.

[Instrument Resources of America]

Nice job, congrats. I'm envious.  Ira.

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[Paul Andrews]

That is great. I plan to make a portable 6 tube clock using some Z5900 tubes, so seeing details of how someone addressed the power issues is really useful.

On Friday, February 3, 2017 at 12:44:43 PM UTC-5, Craig Smith wrote:

I thought I would post a few pictures of my finished Nixie watch that I have been working on for a while and some pictures of the build.

[GastonP]

That's gorgeous!!! Congratulations on an excellent job!!!

[gregebert]

The biggest challenge is designing a high-efficiency DC-DC converter for the tubes; it is the primary consumer of energy. Generally, you will get higher efficiency at higher battery voltage. 

Next, you will need to determine the battery size/voltage/capacity. I gathered a lot of data about various storage technologies (NiCd, Li-ion, NiMH, lead-acid, supercapacitors). Conclusion is what I expected: Li-ion. There are all sorts of Li-ion cells in various size, shape, capacity for phones, tablets, and laptops. Li-ion also has the simplest charging algorithm as long as you dont fast-charge. 

If you just want a portable clock, I'd start with Li-ion battery-packs for power tools. Then you can just use the existing charger.

I'm working on a dynamotor portable nixie clock, and it will use a sealed lead-acid (SLA) battery. Heavy, noisy, but very cool.

[Paul Andrews]

Thanks. I figure I have a lot of research ahead. My intention, at the moment, is to create something that will fit in a purse and/or luggage (not that I plan on taking it anywhere when it's done)! Something no bigger than a cigar case, possibly smaller.

The details on this watch (the accelerometer and the software for example) are incredible. It will certainly make me up my game!

[Roddy Scott]

Amazing build from conception to finished article!

[Craig Smith]

Thought I would post a picture of the new strap I bought for my Nixie watch. Way better than the £3 strap I had before.

[ErikPaul]

Is there any possibility that you could share the board design files? I've been trying to find some but I've not been able to find any, and yours looks top-notch. 

[Roddy Scott]

I am looking at this absolute marvel of skills again and I am still blown away with the intricacy of the whole process.

Sub-miniature work like that is way beyond incredible, fantastic would not even come close.

Well done, Craig on a brilliant watch!

[ErikPaul]

Or if you happen to have any spare boards I'd be willing to pay you for a set.

[Nick]

Really great top quality job. Nice design too.

Where in the UK are you?

Nick

[Craig Smith]

Portreath, in Cornwall

[Nick]

On Monday, 11 September 2017 10:27:25 UTC+4, Craig Smith wrote:

Portreath, in Cornwall

...beautiful area. Cycled round there a bit - lovely place.

Nick