Nixie Tube Clocks

I was interested in building my own table clocks as I didn't have one. Besides, I desided to make their design unique - I used nixie tubes as indicators. This project involves work with high voltage to turn on the tubes, so be careful! This project is also interesting because you can learn how to use AVR microcontrollers.

Here are the components we need:

Resistors - 20x10k, 6x12k, 6x1M, 10x4.7k, 1k, 8x330, 0.22 (2W), 0.3 (2W), 2x20k (variable resistor), photoresitor

Capasitors - 2x1uF, 6x100nF, 2x470pF, 2x470uF, 4,7uF (400V)

Resonator - 32.768kHrz

Inductrors - 2x220uH

Diodes - 6xLED (I used white color), 1N1519, HER106

Transistors - 6xMPSA92, 6xMPSA42, KT3102, KT3107, BC857, IRF840

Microcontroller - ATmega8A-AU

ICs - 2xMC34063AD, DS1307, K155ID1

3xButtons

12V source, 3V battery

6xIN16

Here I'd like to explain how the circuit works. We'll see that the circuit consist of 3 main blocks: power, signals and indication.

The first one is power. Two MC34063ADs give two different voltages - 5V and 180V, which are regulated by variable resistors. 5 volts are needed to power ICs and ATmega. On the other hand, 180 volts are needed to power IN16.

The second block are signals. Here are the main signals that control IN16. DS1307 gives the value of time, then this value is being processed in ATmega, which gives processed value of time to the K115ID1, which decipher these signals, so they are able to be fed to IN16.

And the final part - indication. Here IN16 get signals from K155ID1 and they show the numbers! LEDs are used as decoration. They illuminate under the IN16.

In this project there are some components, which are only SMD (at least, I haven't found their TFT versions). So before testing the project on a breadboard, you should make a simple PCB for SMD components. I have already made detailed instruction on how to make your own PCB (you can find it on auto-avoiding robot post). I've made a PCB layout so you can transfer thier circuit to copper, but I think it's way simplier to draw it by a marker.

I highly recommend to check the work of amplifiers. It would be disappointing if something wrong will happen with your voltage (it's not that bad if it's going to be lower than 180V, but if it's way more higher, you risk to damage your components). While testing, be careful with wires of 180V amplifier. The current is weak, so you won't get any burns, but there would be an unpleasant feeling.

Also you need to test IN16. It's better to be sure that they work perfectly fine. Although, I had a problem with IN16's electrodes. They aren't marked, so I didn't know which one is an anode. I had to find it by checking each electrode.

Now it's time to program "brains" of our clocks. To program microcontroller ATmega8 I've made the PCB, png of which you can find on step 2. When you copmlete this PCB, join pins of microcontroler to USBasp. You also need to download drivers for USBasp. Then open AVRdude and choose this file in Flash section. Don't forget to choose right fuses!

This is the last thing you need to do. Make this PCB. To make two-side PCB you need to fold paper and put the circuit textolite. Be carefule, while making PCB, holes must coincide from both cides. I've made a lot of efforts to make it more compact, so maybe it will be hard to drill the holes for components, but if you have special drills, you shouldn't have problems with that.

I've not yet finished making PCB, but I'll make it as soon as possible to share with the results.