Monotube Nixie Clock

This clock uses only one tube-but at least, it's a big one, a Russian IN-18.

Originally, I used this board as a test bed for a Motorola DC-DC converter to use in place of very expensive Maxim chips. After it worked, I built a clock on the board. This time, I used a socket for the IN18.. I use plumber's epoxy to "neaten up" one-shot electronics projects, and this was used to mount the socket. The circuit board is executed in wire wrap/point to point. Interesting: I noticed that the 74141 used has a '71 date code! Why the big caps? Because I got a bag of 100 for $5.00 on eBay.

A Ubicom SX-28 was used as the processor (I have a good supply of these). The clock is self-rechargeable battery backed, crystal controlled, and displays HHMM <1sec pause> DDMMYY <2 second pause>. There is a piezo for a tick and a single magnetic reed switch for time/date setting. There is a 1/10 second "blink" between digits.

Figure 1. Monotube Clock.

Figure 2. Interior.