Okay, I’ll confess: I’ve spent a bit too long playing Minecraft, both on a shared server, and even by myself in single player. I find it kind of soothing to create models, rather like playing with blocks or legos. But Eric Haines (a long time friend, and one of the people who was most influential in getting me started in computer graphics) has done one better: he’s written a program that allows you to export portions of your Minecraft world, and get them printed as a 3D model. He calls the resulting program Mineways. Check it out:

CMMR-6P-60 WWVB Clock Receiver…

Okay, I’ve been thinking (somewhat abstractly, since I have had relatively little free time lately) about what I eventually want my beacon transmitter to be. One of the issues with it is that I’d like it to be relatively autonomous and lower power: I’d like it to be able to run for weeks at a time without human intervention. I’d also like to use it for WSPR beacon transmissions, much as my original experimentation that I carried out. The trick for making a long term WSPR beacon though is time synchronization: WSPR transmissions begin on even numbered minutes, and must be accurate to a couple of seconds or so. The DS1307 I’ve been playing with only has that accuracy for a day or two: so I need something better. A few ideas leapt to mind:

  • Temperature control the whole thing. I suspect this only postpones the problem for a period of a week or so, rather than curing it.
  • Synchronize using a GPS. I’d only need to wake up for a few minutes every 12 hours or so to keep it going. Still, seems pretty high tech.
  • Add a receiver for 10Mhz time signals. Nice, doable with technology I have on hand, but perhaps needlessly complicated and probably more expensive than…
  • Using a WWVB integrated receiver. These are about $10, and have very low power consumption. Less homebrew, but perhaps a reasonable choice.

Digikey has ’em in stock for ~$10, falling to about $8 if you order 10.

Digi-Key – 561-1014-ND (Manufacturer – CMMR-6P-60).

Khan Academy

I’ve seen the Khan Academy listed a couple of times before, but never really bothered to look at it again until today. I was confused about a minor issue in linear algebra (hey, it’s been 25 years since I took linear algebra) so I surfed over and found the lecture on null subspaces to be clear and easy to follow. The Khan Academy has a huge number of lectures, covering mathematics, economics, physics, and lots of other good stuff. Bookmark it for future reference!

Khan Academy.

James A. Moorer’s Published Articles Page

I was trying to remember the name and author of a paper on implementing linear phase bandsplitting. It had applications to noise reduction, and seemed to be reasonably pleasing when I read the paper years ago, but all I could remember was that it was done by a Lucasfilm audio engineer, and mentioned the movie Amadeus. A few minutes of googling turned up James Moorer, and his extensive list of interesting papers.

James A. Moorer’s Published Articles Page
Linear-Phase Bandsplitting: Theory and Applications (with Mark Berger)