luolamies.org

From a quick peek over at Hack a Day and other electronics blogs it seems like everyone and their cat are doing Arduino projects nowadays. I finally caved in and decided to see what all the fuss is about, and ordered an Arduino Duemilanove from sparkfun, which arrived today. I've only had it for a few hours now, and I already love it. Arduino, together with a breadboard and sparkfun's premium M/M jumper wires equals prototyping bliss ;) With help from the sample programs that comes with the Arduino IDE, I managed to put together a quick IR-reflector controlled servo test thingy in just a couple of minutes with no prior experience with the platform. Doing the same with a PIC would have taken me much longer, despite my greater experience with them.
Installing the PC software was fairly straightforward, even though I run 64 bit gentoo on my desktop. I followed the gentoo instructions and just had to replace the bundled Rxtx.so with a link to the one provided by the distribution. The FTDI driver I had compiled earlier, so the rest was plug and play.

Decided to upload some old, but not entirely useless, old programs I've written. You can find them at the odds and ends page. They are not really usable pieces of software, but might serve as a starting point or inspiration for someone. Currently, I have three programs up:

1. Animtext: A text animation creation tool. I wrote this back in high school (or the Finnish equivalent) to generate the end credits sequence for a student film project. Perfect for cheesy amateur hacker films!
2. powermate qt test: A Qt4 based test program for the Griffin Powermate. Accesses the powermate via Linux event interface. (powermate driver is in the official kernel tree)
3. tablet qt test: A Qt4 test program for (wacom) tablets. Useful for checking if Qt (or X) tablet support is configured properly.
   

A new DrawPile release is out, little less than two weeks after I resumed the project. This was mainly a bug fix release, introducing a new more stable and robust server and fixing many bugs and usability problems in the client.
The 0.5.0 release has one new major feature: an annotation tool. The annotation tool is pretty much like the text tool in other drawing programs, except the text always floats above the actual image. Because DrawPile doesn't have its own image format (yet), the annotations cannot be saved. They can, however, be burned onto the image (in offline mode only, more on that below.)

With this maintenance release out of the way, next up is more features!

Read more...

After a year's hiatus, I decided to start working on DrawPile again.
First thing I did, was rewrite the old server. The new server is QT based (no more other external dependencies) and built as a shared library that can be embedded inside the client and in a tiny standalone shell.
The protocol also underwent a revamp. The new protocol is much more simpler, but also lacks some of the features the old one had (multiple sessions on one server.) The reason I decided to drop these features was that they weren't being used in the client and were and unnecessary complication.
One nice feature the new server has, is the ability to buffer raster data and drawing commands. The server can then efficiently handle new clients with minimal disturbance to other users, and is more robust to boot.

The latest SVN trunk has the new server and a couple of fixes that should make DrawPile much more stable. The drawing code is still slightly broken though. Next up, a new drawing engine, then the 0.5.0 release!

New TC picture added. I increased the size of the top load, tuned the coil better, and managed to increase the spark length from 15cm to about 20cm.

On top of the toroid I put a sharp screw to act as a breakout point so I could more easily judge the length of the discharge. I then adjusted the tap point in until I got the longest sparks.

I also adjusted the spark gap spacing. Finding the optimum distance between the electrodes can be tricky. If too narrow, the capacitors don't have time to charge enough or the gap won't quench; too wide, and the transformer might burn out. I previously had a problem where the coil would run for about 30 seconds, then the gap would simply stop firing and the transformer emit a buzzing sound. Luckily no lasting damage was done. I narrowed the spark gap a little, and the problem seems to have gone away now.

Read more...

Just added a new page about my Tesla coil.
I first started building the coil over ten years ago, but never got around to finishing it. My new coil is not exactly same as the one I first started building, but I did use the components from the original one.

The coil is around 35cm high, uses a 4kV neon sign transformer as its power supply, and currently produces sparks about 15 to 20cm long.

Read more...

I decided to change the website layout back to something simpler. Some content, such as the old blender tutorials and models, I dropped altogether.