Saturday, March 27, 2010

Last Judgement

Here is a (Swedish) text I've written on an existentialist theme.

You can access the text here

It's about Gilgamesh, the hero of old Mesopotamian mythology, and the thought that all men will judge them selves on the threshold between life and death.

Print the pdf on a double-sided A4 and fold it 8 times. This makes for a convenient, truly pocket sized, short story format.

Wednesday, March 24, 2010

Don't be evil; Be Harmless!

Ok, I admit it. I'm one of those people who think that peace, love and understanding isn't so bad after all.
Since I occasionally share free (libre) source code on the Internets, the question of how to license it naturally arises.

To that end I've developed the Harm-Less Permissive License (HPL). It's a permissive, non copyleft, software license. It is based on the FreeBSD license but with one additional restriction; the "harm-less" clause. It prevents software, licensed under the HPL, to be used for harming humans or animals.

Check out the link above for more information about the license. The license text is available here.

Update 1: I've started a collaboration with the organization People for the Ethical Threatment of Animals (PETA). They are running a story on the HPL and are helping me host the HPL document.

Update 2: The land slide has started. has the story: PETA Creates New Animal-Friendly Software License. This is my first on Slashdot...

Update 3: The news have made it to the Ubuntu Forums: Move over GPL - meet the HPL! 

Update 4: HPL has recently made an appearance in Osqledaren; the student magazine of the Swedish Royal Academy of Science. Read the (Swedish) article: För dig som inte vill döda

Sunday, March 14, 2010

Newton vs Kalman; Estimating Motion

Surprisingly often I'm faced with estimating the position of something that moves according to Newtonian laws of motion in one dimension and with random acceleration.

A fast and pretty accurate way of doing this is to use a Kalman filter. I've finally gotten around to implementing a specialized version of this general method, dedicated to my simple estimations needs. You are welcome to use it (it's HPL licensed).

Have a look at the image if you want to see how it performs in a sample case.

Saturday, March 13, 2010

How I lost my SMT virginity...

Finally! My first PCBs from Batch PCB were delivered yesterday. This one is a double sided USB / serial converter, with solder masks and silksceen and it looks good! Very good.

The design is a FT232 IC breakout board. If it works good, I'm going to use it to add USB support to many of my future designs.

Well, how does it look when all the components have been soldered in place? Have a look at the second image. Not bad ey?

SMT soldering was a bit harder than I had anticipated. Mostly because the components are really tiny. The 100nF caps were almost impossible to place; I need to get me a new pair of really pointy tweezers.