Propeller-powered IN-12 Nixie Tube Clock

smbaker

Just finished my latest propeller project and thought I'd share. This one is a nixie tube clock, using IN-12 nixies. Time is kept using a Dallas 1302 RTC. The next revision of the board is going to have a footprint for an on-board GPS (current board has an expansion connector that could be used, but requires a custom cable to hook up a GPS module) and a number of other minor changes like changing the orientation of the power jack, adding a header for power in, etc. Generally it was a fun project, the first nixie clock I've designed myself, and as usual the prop was very easy to program to do the task.

Scott

xanadu

Awesome, I have not seen much Nixie activity laterly.

Mark_T

Oooh, look forward to some more details - have some IN12B's waiting for a good project...

Bean

Scott, What are you using to drive the Nixies ?
Any chance of posting a schematic ?

Thanks,
Bean

Mark_T

A careful look at the photo suggests the top two chips are 74141's, certainly there are signals going into pins 3,4,6,7 which is strongly suggestive. The transistors would be anode multiplexing I guess and the third chip at the top could be shift-register to drive those? I also notice the 32768 crystal for the DS1302 doesn't have a ground plane under it as recommended in the datasheet ;-) [ caution: engineer reversing! ]

Heater.

smbaker,

Drat, you beat me to it. Thanks to localroger I have a bunch of Nixie tubes waiting to fulfil my dream of a Propeller + Nixie device. Having had them for a year I've been to busy to get started on it. I'd like to use 6 or 8 of them as a general purpose instrument, clock, frequency counter, random number generator, whatever.

My first digital project was a TTL and Nixie clock back in 1973!

Look forward to seeing more details.

Martin Hodge

Nixie = FTW!!!

smbaker

Bean wrote: »

Scott, What are you using to drive the Nixies ?
Any chance of posting a schematic ?

I'm using K155D, which I believe is equivalent to the 74141 but seems to be more easily available, especially on ebay. The anodes are driven by a couple of transistors. Tubes are multiplexed two at a time. The remaining chip on the board is a TL494 used for the high voltage power supply. There are chunks of schematic and a little bit of discussion up on my blog post at http://www.smbaker.com/propeller-powered-in-12-nixie-clock.

I didn't know a ground plane was needed for the DS1302's crystal (I'm not one who does a good job of reading datasheets!), although there is actually one on the bottom of the PCB (crystal could be flipped from top to bottom).

Scott

JonnyMac

Very cool. I have a friend who builds high-end animatronics (see www.characterdynamics.com) and a couple of his projects use Propeller boards. Last year I did a program that included output to a set of Nixie modules for a steampunk DJ setup that features Frankenstein and Dracula type characters.

Mark_T

smbaker wrote: »

I didn't know a ground plane was needed for the DS1302's crystal (I'm not one who does a good job of reading datasheets!), although there is actually one on the bottom of the PCB (crystal could be flipped from top to bottom).

Scott

RTC chips drive their xtal's at extremely low power levels (a couple of uW) and are high-impedance - so are very sensitive to electrical noise when the circuitry is powered up - hence the need for ground plane around the xtal. If you were unlucky this would show itself as the clock keeping poor time or stopping only when the device is powered up. You seem to have the xtal well away from the SMPS and nixie drivers which are the obvious source of noise.

jmg

smbaker wrote: »

This one is a nixie tube clock, using IN-12 nixies.

Impressive, but no Neon light Colon : ?

I even surprised myself, by finding a Neon Lamp tagged "new product from Lumex" at Mouser, and with a 2012 data sheet !
GT-NE4H1125 11c each /10+

smbaker

jmg wrote: »

Impressive, but no Neon light Colon : ?

I've never been a big fan of the colon display in Nixie clocks. I did mean to add an optional spot to the board revision, but I forgot. Ah well, I guess I can start up a list of things that will be in board revision #3.

smbaker

Update - the revision 2 PCB arrived on Friday and I've constructed a new version of the clock. This one has the GPS module mounted directly to the PCB (optional DS1302 footprint is underneath the GPS module). I also designed a custom acrylic case for it. Below is a picture of the completed clock in case:

and a youtube video showing a few stages of construction:

http://www.youtube.com/watch?v=rkoEvS9Bu4s

Cncjerry

This is pretty cool. I have a nixie clock I built from Nixie Clock Kits and it has been running within a second since last November. Mine has 6 digits with autodimming at night. Love it though I have to cover it every night, sort of like putting it to sleep.

It uses a pic chip (boo) and a timing loop to get the accuracy which I can't believe is so close but I spent the time and adjusted the counters for months. I also don't use a case and here in Northern Cal it is always around 65 in my house. I'm sure that plays into the accuracy.

I would love to buy a board if you get to the point of adding two more digits. l love to watch mine count.

Jerry

smbaker

My nixie clock has mutated into a Nixie Thermometer/Hygrometer!

I'll be changing the "H" to a "%" when I get some IN-15A tubes on hand. Temperature/Humidity measurements made possible by WBA consulting's SHT11 module!