Why talk about it now?

Ever so busy…

Posted by aonomus on October 26, 2008

Well, as usual I vanish off the face of the internets due to being too busy, but at least I have plenty of juicy things to show you guys. I’ve finished off my solid state tesla coil (SSTC), made most of my spectrum analyzer, and been doing leatherworking on a Halloween costume. This post is very image intensive so for the sake of anyone with 56k I’m going to separate it from the main page.

First off, the SSTC – you can see the progress ‘log’ of sorts on the forums. For the most part I had a few initial problems with overly-high coupling blowing suspect MOSFETs (IRFP250N’s via a ebay dealer ‘thai shop etc’). After blowing 8 MOSFETs I replaced them with some ON Semi MTW32N20E MOSFETs which have nearly identical ratings (but have slower switching speeds) which have given rock solid performance since replacement.

Photos of the SSTC follow:

Next up is a quick update on my spectrum analyzer:

I have gotten boards etched and populated, and a full function test has been performed however I have been unable to get the two highest frequency channels from functioning properly.

Photos of the spectrum analyzer follow:

Also a early low audio quality bodged-together test (unlit LED’s due to using odd cables to connect):

And last but not least, my most recent endeavor has been leatherworking to make additions to my Viking Halloween costume. I made a pair of bracers, a belt and scabbard, and I’m sprucing up a metal helmet (still a WIP). While the scabbard is a bit mediocre, this is my first ever attempt at making stuff out of leather and I think I’ve done pretty well. I’d like to give a shoutout to Anthony from Tandy Leather of Mississauga for giving me tips and hints.

2 Responses to “Ever so busy…”

  1. Matija said


    First, thanx a lot for the trouble of making this spectrum analyzer!
    I wanted to ask You why don’t U use preamp & filter schematic from that velleman kit (I can send it to U if u give me your mail) cause it got 10 channels and it should work properly, right??
    And it would be maybe good to put some small C near diodes so that they are not so responsive, i presume it would be much more pleasant to the eye.
    Keep up the good work!!


  2. aonomus said

    Its been a while since I wrote the post up, I’ve solved the preamp problem for the most part using a LM358 from scratch giving a mostly rail-to-rail amplification since I don’t need any real current draw through the preamp, a single chip is no problem.

    As for the responsiveness its been a long time since that video was filmed, since then I’ve tracked the problem down to a defective Vcc/2 stage (ie: instead of -9v, 0, +9v I use 0v, 9v, and 18v) causing the Fliege bandpass filters to not work properly.

    My current dilemma is the decoupling caps between the preamp and bandpass filters do not pass the full frequency range without distortion, The top 2 bands do not work at all which is my main hurdle before proceeding with building the enclosure….

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