IN-14 Nixie Clock

I’m returning again with a new Nixie project. I have to confess, I am addicted with tube valves.

In this project I will show my new IN-14 nixie clock.

As I told in the previous Nixie clock case project, my clock is based in the Andrea’s nixie clock. You can see his project here: https://www.instructables.com/id/simple-user-adjus...

I made some modifications, some improvements according what I want in a clock (minimum electronic parts as possible). In my future nixie clock (now in construction phase) I will show in details step-by-step all modifications I made, but in this project I will just show the modifications listed below:

- The original project is designed to power the circuit with more than one specific voltage, and to make it possible one switch is necessary do select the voltage that will be used. I removed this switch and 12 VDC must be used (you can use a PS that provides VI =11.5V to 24V).

- To turn easy to install the pcb in any case, I removed the push buttons from the pcb, so you can install the buttons direct in the case.

- I removed the SET button. I don’t see any useful application for it. We have two push buttons to set Hour and Minutes, if I need to set the time I can use them. And if for any reason that I am not considering you need to return the clock to the original set time, just turn off and turn on the clock using on-off switch (S1).

- I wired the tubes direct without using a Tube PCB. Doing it I can use any nixie tube, not only IN-4 as the original project and I gained mobility to install the tubes in any position I want.

As you can see, what I did was just minor improvements. Let’s rock it…

First step is to decide what kind of valve you will use, so you can select an appropriate case. I choose the valve model IN-14. The original project uses valve IN-4, but if I am not wrong you can use any nixie valve (only if you wire the cables using cables, not the original PCB).

My original sketch:

To give a steampunk air I used a metal pipe connection to support the valve (3/4” Female to 1/2” Male Pipe Connector Thread Reducing Fitting).

The valve IN-14 has thin wires as connection. If I am not wrong there is no socket available for this valve. Sometimes this valve is sold with one plastic base. I found one interesting tip on the net that shows how to convert this base in a socket ( http://www.electronics-lab.com/make-your-own-nixie... ).

Using the plastic base, you can increase the original holes in the base using a drill and install one metal pin to hold the tube in place, we just need to cut the tube terminal with the correct size (around 7mm). I used pins from one Round Female Pin Header connector. It avoids welding the tube wire, turning the tube replacement much more easily.

During a visit in a home appliance store I saw one wood box with the perfect size for my project. In fact it’s made from cane. As cane it’s not so hard that normal wood, when I drilled the valve holes, the surface was damaged. So I had the idea in cover this part using faux wood contact paper and the final result was very satisfactory. If you decide to use cane box, a good idea is to use adhesive tape to protect the surface during the drilling process.

As my project is based in the project informed above, I will not enter in details regarding the electronics, PCB, programming, etc…. as it is very well detailed in the original project. Please visit that page to obtain more information.

Using a hand drill and a drill bit of 1.5mm enlarge the original holes to accommodate the pin inside. Pay attention and leave a small part of the original hole to hold the pin inside, DO NOT ENLARGE the entire hole.

Valve base: As the metal support is a little large than the tube valve, the valve will pass through the hole. I solve the problem using a plastic blind plug with the same internal size of the connector. I just cut the top of the plug to pass the wires through and it turned a perfect holder to the valve. You can adjust the position of the plug moving it clockwise or counterclockwise.

Commands: as described in the beginning I decided to fix the controls on the case, it turns easy to install the pcb in any case.

Cables: as I am not using a PCB to weld the tubes, it is necessary to wire the tubes directly one by one. It's necessary to be patient in this phase, but to me this is the best solution. You will gain a lot of mobility doing it. Before interconnect the valves, test each one separately. If you made any mistake it will be much easier to identify the source of the problem . As described in the original project, each anode has a resistor in series, and I decided to weld them directly in the connector as showed in the picture. This project uses Multiplexing technique to control the tubes. Resuming, Multiplexing is the technique of using one wire to do the work of many.

I make my PCBs by my self and I don't spend much time with cosmetics, that is the reason why my PCB is so "ugly". First I install the electronics responsible to the power supply (180 VDC), so I can test to see if the circuit is ok. Connect one valve and select one digit to see if the brightness is good. Before to connect, check using a voltmeter if the voltage is correct (around 180 VDC or the correct voltage specified by the tube vendor). I used colored wires and each digit has one specific color and they are the same in all valves, it will turn your work much more easy.

Now its time to assemble all the parts. First take the main board and put it inside the box . Then connect the control wires (minute and Hour adj. switches, on-off switch and power supply connector). Last step is to install the tubes. Take care to not connect the anode in the wrong base connector. This will generate a short circuit burning the valve.

After everything was in its place we assemble the house bottom case cover and power it on to enjoy the mesmerizing light that come from the valves.

Tip: I used POPSICLE STICK to build the case cover. I did some holes using a drill of 6mm to help the air circulation inside.

In my case when I turned the switch on..... the last tube was showing several digits on at the same time. I spent a long time checking the wires and etc.... nothing!

But as said my favorite football player (Emmitt Smith, Dallas Cowboys) “I may win and I may lose, but I will never be defeated.”

I left the clock on and went to shower, when I came back, for some unknown reason ..... the clock was running smoothly!

That is it! This is a difficult project that requires a lot of patience, but when finished, the feeling of satisfaction is indescribable .

In my next nixie project I will show all steps (for dummies). I promise!!! 8 )