Archives July 2013

Sunday, 28th July 2013 - 21:00:44


I scored some second hand Cisco 7940 and 7960 handsets to start experimenting with Asterisk. They look very good for the price.

Thursday, 25th July 2013 - 15:18:27


Had a bit of fun today with my site after discovering nearly 2000 spam comments. Thankfully the comments go through an approval system first before they are visisble.

I also threw django-grappelli on for a pretty admin area. It looks quite neat.

By adding a newer jQuery and jQuery-UI to the admin section I also broke the Zinnia tag autocomplete. I rectified this by replacing the autocomplete_tags.js which utilised Jörn Zaefferer's jQuery plugin with code to call jQuery UI autocomplete.

Thursday, 25th July 2013 - 08:00:30


Some of the brewing gear got justified today in the blackout as we could enjoy hot coffee in the morning with no power.

Monday, 22nd July 2013 - 21:53:48

Ooops thats not the anode

Oops. This is what the tube looks like if you get the pin mixed up. But be cautious - as this can damage the tube. In this case the decimal point is being used as the anode instead of the actual anode.

Thursday, 11th July 2013 - 17:55:19

GR-211 Nixie Running

Wow, that tube looks awesome running.

I set up the improvised high voltage supply to 250V DC per the data sheet and then dug about for about half an hour to try and find a 22K resistor which was 1W or larger. No joy, but I did manage to find some resistors that match the tube. Some 12K 2% resistors, they look like maybe 2W. Put them in series and we get 24K, or 23.5K in ths case because they aren't in spec (although now that I think of it, they probably are - just, It's about 500ohms out, the 2% gives you 240 ohms leeway each)

With that in place I measured the short circuit current at 8mA. I adjusted it down a bit further to get the current down and ended up with just over 6mA and just over 180V under load.

Next I quadruple checked the datasheet to ensure I had the right pin for the Anode and applied the 180V to the Anode. Then I grounded each Cathode and watched the digit light up. You can see in the photo the number 5 lit.

Sunday, 7th July 2013 - 00:50:47

GR-211 Nixie Tube

Wooo! A Nixie Tube. =) Thanks Dave!

This is one of the larger Nixies, it's a GR-211. It has a 170V 5mA strike voltage. We didn't get a chance to try it during the BBQ.

Friday, 05th July 2013 - 15:23:57

400V DC Isolated Supply

In anticipation of my mate bringing a Nixie tube over to look at I knocked up a quick variable high voltage supply.

It has a massive unloaded voltage of 418V in the photo.

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