Pending Sapience

Nixie clock project 0.6

Since my PS2 has foiled my attempt to replay Another Century’s Episode 3 [I felt like piloting Nirvash after watching Eureka Seven AO okay??], I suppose I will finally do my nixie post.

The first thing I did was research currently extant nixie projects, of which I found many! ArduiNIX was one of the more accessible ones I looked at. It’s a “shield” (expansion board along the IO channels) for arduino that multiplexes the digital channels and powers the high voltage nixie displays.

Then I actually bought stuff, which required me to have money, so…had to wait until I got my new job =) The nixies came from the old soviet bloc…but they actually arrived sooner than expected; sooner in fact than my arduino which I ordered a week later. Whoops.

The first actual step in the project was testing all my nixies to make sure all the numerals work. This required soldering up my ArduiNIX board and using an anode lead and a cathode lead to ensure each individual digit lit up properly. Each nixie has 11 digits (0-9, decimal). I then soldered the nixie tubes into a small base with an LED and wires soldered into that. Because each nixie required 12 wires (each digit + anode), this was…time consuming. Here’s a pic of what I mean.

Here’s a video.

As you can see, my first setup wasn’t pretty. I used an IDE cable and butchered molex cable because I couldn’t find any single-pin ribbon cables at my local electronics store. Fortunately I later found some online which made much less of a cable mess.

For the prototype I decided to use some cheap cardboard box; I’ll replace it with an attractive wood case at which time I find one the right size and suitably nice-looking. I hooked up the other 5 tubes to the ardunio and downloaded a prebuilt clock code. It still needed some tweaking due to the weird configuration of the digits in the code, but here’s what it looked like after that. I also set the decimals at the traditional position of the : to flash every even second. I decided starting at 12:59 was much more dramatic.

From those videos you can actually determine a bit about the prebuilt code. It has crossfading built in (transition between different digit states smoothly), which is kind of nice (but really cool for the decimal digit). Unfortunately the video also picks up the flicker of this code, due to the crossfade being improperly configured (for my tubes). This is visible for humans as well and kind of annoying. Even more unfortunate is the fact that not all digits are lighting fully. The code is configured to light two digits at once, which is probably okay for the smaller nixies used in the standard ArduiNIX kit, but doing it that way doesn’t provide enough current for the IN-8-2 nixies. I tried increasing and decreasing resistance to compensate, but it didn’t have significant enough effect so I just hacked the code to only light one digit at once and removed the crossfading. Video. The backlighting is also on, but unfortunately one of the LEDs appears much less bright than the others >____>;

Here are some of the innards. They’re kind of a mess due to my overestimating cable length requirements. Oops.

More recently I added a switch to control the backlighting and a pair of microswitches to set the time. And that’s about it for the v0.6.

Here’s the image album if you want to see any of the images again without scrolling through a lot of words.

I plan to add a thermistor in the near future to enable it to display the temperature.