Latest clock

[Marko Kraljevic]

This is my most recent clock. I'm new to the group and figured you guys might be interested!

It's powered via PoE (48V over ethernet, the 802.3af standard), and synchronizes time through NTP.

It has a DHCP client so you just plug it in and go.

The software is based on the tuxgraphics ntp clock, but modified to suit my peripherals and the nixies, of course.

It uses HV5812 HV shift registers to drive the nixies. A zener clamp clamps the 'off' state to +70V or so, which is enough differential to turn the tubes on and off.

Power supply is a flyback with 48V input, 5V & 200V output. It uses the LM5070 IC which has integrated PoE authentication bits. The transformer seems to run somewhat hotter than I would like, and I'm concerned about it. I'll have to try retrofitting a larger core I guess. I'm still pretty new to SMPS design.

What else... It's got a relay to drive a horn or lamp, CP2102 USB <> TTL 232 IC for.. debugging or setting the time or...

Also has buttons and a battery backed RTC if you want to use it without the internet, for some reason or other.

[threeneurons]

Hi Marko,

I don't I've seen a network powered nixie clock before, unless you count USB ports. I saw that you posted it earlier over at ARF:

http://antiqueradios.com/forums/viewtopic.php?f=2&t=214354&start=40

I was wondering what that relay was for.

Switching power supplies are welcome here, though they do cause reception problems, too. Sometimes a few of us have clocks that sync'd by radio time sources, like WWVB. Then we have to momentarily shutdown the supply, while the time is being updated.

Thanks for sharing.