brainwagon

Sigh. The new version of WordPress is doing stupid things with images. I’ll fix them later.

Okay, so roughly a month ago, I said that I was interested in rebooting this blog, and then once again I lapsed into silence. It’s tough to make something a new habit, even if it is something that you wish to do. But it’s not because I’ve had a lack of new things that I’ve been working on: it’s simply that I’m out of practice in terms off writing about them. Rather than try to frame each of these different things into a consistent, well framed narrative, I am simply going to dump out some of the things that I’ve been working on.

I’ve been interested in writing emulators for old computers for quite some time. In the past I’ve written an emulator for the DEC PDP-1 so I could run SpaceWar!, one of the very first video games. A couple of years ago I wrote an emulator for the 8080 microprocessor so I could make an emulator for the original Space Invaders games. It worked rather well. While goofing around a few weeks ago, I tried to recompile it, but had some difficulties which I eventually ironed out. I also relearned a small amount of the subtleties of that hardware which I had forgotten. Nifty. But it also got me back into being interested in writing another emulator.

I had already been doing some research into the old Atari arcade game Battlezone. I had long wished to actually understand more about how this game managed to achieve the 3D graphics which were quite revolutionary for its time. I had also considered trying to figure out how to extract the vectors that it draws, perhaps with an eye to creating a bit o hanging wall art using EL wire and the vector shapes. Luckily, a bit o work on the internet lead me to the vector ROMs and how the backdrops were encoded. This, combined with some very simple (and very slow) vector rasterization code I wrote lead to me extracting some very cool outlines directly from the arcade roms.

That was fun. I briefly considered writing a full emulator for BattleZone, but it seemed difficult because while the main processor for the machine was my old familiar pal, the 6502, it also included a custom processor that was designed to handle the math necessary to render the tanks in 3D.

So instead I embarked upon creating an emulator for the Atari game Asteroids. It too had a 6502. I started trying to write my own emulator. It’s pretty straightforward to do a half-assed job of this, and I got about 60% of the opcodes implemented before I got grumpy, and decided to cheat by using http://a rather nice little 6502 emulator core which was placed in the public domain. Over the next several days, I managed to get most of the emulator cobbled together while watching Psych reruns. It started out pretty rough. In particular, deciphering the abstract functioning of the vector generator took me a while to sort out.

But I eventually got it sorted out. Note: the 6502 emulator above doesn’t have a proper implementation of BCD mode in the 6502, which makes the scoring incorrect until you sort it out. In the end though, I got it working.

In other news, I went to an estate sale and got a couple of other goodies, including an antique PS&W draw knife, an old Vlchek auto wrench, and a very large (75 pound) Rock Island No, 574 vice.

I cleaned up the draw knife with some 320 sandpaper and WD-40, and it turned out pretty nice. I soaked the wrench in some vinegar for 18 hours, and then hit it with a wire brush and it turned out well. The vice is a work in progress. I disassembled it all to base components, and in the process got tons of old grease all over my workbench. What a mess. I applied some Citristrip to bring the entire thing down to bare metal, and now the project is stalled while I consider how I’m going to finish the vise. Here is the new one with a smaller Babco vise for size comparison.

In other news, we’ve been taking care of a couple of feral cats whom we’ve named Whittaker and Patches. Whittaker is a 10 year old male. He got into a fight with something six or eight weeks ago, and we ended up trapping him and taking him to the vet, where he got some antibiotics and was neutered and microchipped. He tested positive for FIV, which makes him not a good candidate for adoption given that I have two indoor cats already, so he’s back out roaming. Patches is a female who was obviously pregnant around the same time. We’ve suspected that Whittaker is the daddy for a long time, given that they occasionally show up together. She was obviously nursing for some time, but we hadn’t seen the babies. Until yesterday.

Patches and Whittaker showed up with five kittens, three of them sort of patchy (although with little orange that we see in mom) and the other two inky black solid color. My guess is that they are 8-10 weeks old. We are trying to see if we can lure them all down again at once so we can have them trapped, get mom fixed and maybe see if we can get the babies rehomed before they go full feral.

I’m running out of energy, but a couple of weeks ago, I was experimenting with creating anthotypes. They are a photographic process that uses non-color dyes, usually derived from plants. Of particular interest to me was using the spice turmeric. You can create a solution of a non-color fast yellow dye by dissolving some in alcohol and painting it onto paper. You then can sandwich a “negative” (which is actually a positive) which I created by printing a black and white image onto some clear transparency, and then exposing it in the sun for around 40 minutes. The yellow bleaches out and yields a yellow print which has very low contrast. But you can “develop” this print in a solution of borax and the yellow will turn a darkish brown. The print is still low contrast, and has questionable longevity, but it was a fun afternoon to give this a whirl.

Anyway, Patches is now out back and looking for some food, so I think I’ll give her some and prep for work. I hope you all are having a good week.