Fixietube - Fake Nixie Tube displays

https://github.com/davedarko/FixieTubes

I wanted to use the "square wave out" from the DS3231 module for a blink-every-second LED, but the control register for the DS1307 and DS3231 were different, so I had to switch libraries a bit.

I used an old cell phone charger and soldered it directly to the arduino, since I had no plug for the connector I wanted to use.

The challenge here was to design a case that fits 4 displays and is also printable. Each fixietube socket is 5cm x 5cm - so putting them all next to each other would already mean a case of more than 20cm width, something that held me from designing it in the first place for a long time. But then I figured I could print in a 45 degree angle and the case of 24cm x 7cm was not a problem anymore! Well, at least in size.

The first shell I've printed over night came out almost perfect, but the second half cracked. I used a hot air and the screws to fix the posture of the shell and then extruded ABS into the crack to seal it. Reworking it with a file and acetone I got some pretty satisfying results. I may reprint this with z-ultra some day, since it is supposed to be not that expanding etc., but for now I'm quite happy that I have a case :)

ToDo: The arduino and the time module have to be placed somehow, and I have to come up with a way to set the time module once in a while, because of all of the gas lamps in Germany that need the summertime settings. The power connector is not connected yet.

and it was so simple! I didn't even change one line of code. I also found out the reason for why the modules were so cheap (1,10EUR) - there were no batteries with it. But I luckily took out the one from the DS1307. So coming up next should be a nice case, finally.

I'm still not satisfied with the running off RTC called DS1307 and some research gave me the DS3231, which is a temperature corrected, very accurate clock module. It seems interchangeable with the DS1307 without so much hassle, so I bought some modules for 1,10 EUROs on ebay. It can't be right when the chip itself costs 3,50 on digikey, but all the modules were the same, the only difference was the price tag, so I took the cheapest. I'm tempted to measure the 1kHz square wave of the DS1307 though. Work on a photogenic case is still something I have to do, I need that 100th skull!

On the same day after switching the battery I've noticed that it still went ahead way to fast, so I ordered a new oscillator for the module. Now after switching the quartz I'm already off by 4 seconds again and out of ideas. Got to google that - again. Hmpf. Ideas anyone?

So today I pulled out this project - I noticed that it was running too fast and I also wanted to build a nice case some day so it went in a project box. I checked the battery since I found a deviation of 2 hours leading a bit too much for this timespan. The battery read "LIR2032" and 3.6V on it and measured 4V which got me thinking and searching for some data-sheets. First I seem to have scored a rechargeable lithium cell (http://www.powerstream.com/p/Lir2032.pdf) which came with the module, but the datasheet of the ds1307 gives a maximal voltage of 2 - 3.5V for the battery input - I'm gonna grab a CR2032 rated 3V and hope their mistake didn't break the module board :D oh boy.

Today I gathered some code for the ds1307 module I bought for this "fixie-tube" clock project. I used a cheap arduino clone and some wood to hold the sockets together. Soldering a cable was annoying, but I succeeded in the end. The setup is still temporary, since I want a laser cut case for those beauties. Right now they are to far away from each other, you can't read the time with one glimpse.

so now I got the printer of my firm at home I was able to test and tweak the design of the jam jar sockets. Now I have four printed out and need to connect the displays with an arduino.

Once again I'm not quite satisfied with the printing quality of my printer, but It was enough to print one socket for a test.

http://www.thingiverse.com/thing:470666

So far I have 4 of those fixietubes ready and since I only need 4 for my clock and I soldered for 2 or 3 hours I leave it with that for today. Next up will be to wire up the shift registers, connect the ds1307 RTC module and 3d print a base where the glass can be screwed in.