Archive for February 25, 2014

Oscillations

Made sure I did something constructive today…

Added on to my circuit board from the previous post. This is the heart of any clock: the crystal oscillator. I’ve explained it more or less in previous posts, a 4.194304MHz quartz crystal is set oscillating while a CD4521 24-stage frequency divider divides the frequency in to discrete steps by powers of 2. Of course the primary use for this is to get a clean 1Hz output from the thing.

After smacking my forehead and soldering one joint I forgot about when the initial test didn’t work. I’m happy to report it is working just fine. Here’s some pics and a video of the scope readout on my crappy (but working) PM-3200:

oscpcb1
oscpcb2
oscpcb3

I think I had it set on 2 volts per division and there’s some parallax error from my crappy camera skills but there you have it. You can see that half at least of the board is still unpopulated and this will house the two seconds counters which will take the output of the 1Hz (i.e. one pulse per second) and convert that into counting minutes. Unfortunately, I highly doubt I will be able to fit the minutes and hours counters on the board (though it might be fun trying, $10 says I burn myself) so they will live on a board which I will mount on top. Beyond this, it is going to be a very boring wiring maze.

I have yet to find a suitable box for it, time to raid antique and junk stores methinks… if only I could work with wood (and make it look good) I would build my own, but alas, I stink at carpentry.

Progress amid much laziness

Nixie supply soldering coming along!

nixieclock_ps3

Winter is hard, it’s cold, there’s not enough food, the hounds attack… wait. That’s my video game. Relevant though, because that’s exactly what has been distracting me from making serious progress on my electronics projects. I am referring of course to Don’t Starve. Sometimes though, I have to force myself to haul my ass down to the basement and get something done – or I never will. I have a long history of procrastination and it’s time I finish a few things with electronics before the ice thaws.

Today, I managed to get down there and solder some more. Like many things, it’s easier once you get into the rhythm of it. I’ve never been great at soldering (see my previous post on the voltmeter sub-project) but it’s exactly true that practice makes perfect. I’m finding with each successive try, I am making better, cleaner, shinier joints that are less likely to short or crack or be non-functional.

nixieclock_ps4

Today is a landmark. The first time I soldered something up and it worked. I didn’t have to reflow any joints or troubleshoot mistakes, it worked. I couldn’t be more pleased. From the pictures here you can see me assembling my nixie clock and what I have done so far is solder on a triple power supply. The first two are quite simple using LM78xx regulators to gave me +12V and +5V. No explanation needed there. The second feeds off the 12V and uses a switchmode circuit to bump it up to 170V – the butter zone above strike voltage for my nixie tubes.

After a couple hours of soldering and a quick trimpot calibration, it reads 170.2V. Brilliant.

Next step is to fit the oscillator into the small space beside it to the left which consists of a 4521 frequency divider, a crystal and some passives.

Updates suck ass

We’ve all been there. We get a notification “oh updates available, coo” and blindly allow it. Then BANG, something that worked this morning is new perma-broke. Every platform imaginable falls victim to it. Some is by accident, a big “whoops” by developers pushing features forward accidentally breaking other things in the process. Others, are by design.

My particular case today was a simple update of the Ubuntu system which runs my XBMC media pc. Figured that’s kinda safe. I ran it and suddenly XBMC wouldn’t open. What? Now it complains that it requires 3D acceleration. But but but, it has a bloody radeon card in it. It worked this morning! Bastard. So, after some poking I discover it has installed the newest Catalyst drivers which OBSOLETED the card in my girlfriend’s old laptop. Thanks.

Rather than leaving it alone in its WORKING state, it chose to overwrite it with some new garbage that doesn’t work. Thanks a bunch, douche.

In desperation I tried out the Gallium open source drivers and they did work. I was much relieved. A small, but thoroughly annoying problem is my frame rate seems to have been reduced by at least 50%. Choppy and horrid on something that I usually show off to other people not only as an example of Ubuntu’s prowess, but XBMC’s clear superiority in the field of media centre software.

Not wanting to leave it alone, I pursue the issue. Apparently, I can grab some legacy drivers, fantastic! Installed and it worked as before.

Here’s how, open the terminal and:

  • sudo apt-get remove –purge fglrx*
  • sudo reboot
  • sudo add-apt-repository ppa:makson96/fglrx
  • sudo apt-get update
  • sudo apt-get upgrade
  • sudo apt-get install fglrx-legacy
  • sudo reboot

With any luck, you should be restored to former usefulness as I was. If not, you can always revert by:

  • sudo apt-get install ppa-purge
  • sudo ppa-purge ppa:makson96/fglrx
  • sudo reboot

I probably missed the obvious method of rolling back the package (if that was possible, check first) but this worked a treat.

The moral of the story, which I DID know but in temporary insanity forgot, is: if it ‘aint broke don’t fix it. Or in this case, DON’T UPDATE EVER. It’s a sad case that manufacturers deliberately obsolete their products this way, it would have cost them nothing to leave the working driver in there. Thank christ I got it working again just in time for some movies tonight.