Nerdy Texts of Analog and Embedded Systems Wizardry

So over the last couple years I’ve been building different variations on this thing for my client/buddy Cory. It’s had many names but the one we tended to call it the most often was the “Video Game TiVo”. It’s basically an AVR with a ton of Atmel Dataflash as well as some Vregs, level translators, and RS-232 chips.

The idea with these guys is that they sit around on a video game controller and log what the user is doing, and then spit that biz back out when you tell them to. The original ones simply hung out watching or asserting the actual switch lines using WPUs and the like, and as time went by they began to actually replace the controller interface entirely and deal exclusively with serial. Depending on the game system, they can sometimes play a game back deterministically, but mostly not because of RNG and/or timing issues. Either way, they’ll record MONTHS of game and can loop arbitrarily, etc etc. They also have a fancy terminal built in for communicating with a PC and recognizing different video game consoles.

Cory wanted them so he could throw infinite gutterballs in Playstation Bowling games. They do that just fine :-)

This one was tested on a PS1 and the canonical bowling.
This January I had geared up to finally make a TON of them so Cory could just have them handy and not need to call me when he needed one, and this was the final test run before we went into production.

This labor of love and money was also for Cory. Basically, there are these two weird Chinese merchandise stands that get sold at places like Spencer’s, and Cory was like, make one go a few percent slower than the other one. I think originally he was thinking stepper motors or something which is why I got involved, but it was a lot more low-level (in a wedge-screw-pulley-inclined-plane kind of way and not so much an assembly language kind of way) than that.

Inside one of these things is a reversible synchronous AC motor with a toothed belt linkage. A quick test with the Variac proved that, yes, their speed was independent of input voltage. Turned out the easiest way to get the speed differential was to pull the original transmission parts and replace them with XL drive pulleys and belts. The OG stands use a 3mm (I think) Chinese pitch system which is kinda hard to find around these parts. McMaster saved the day as usual but now I get my goodies from my pulley people at B&B Manufacturing who have likely forgotten more about power transmission than I ever hope to know. One thing about McMaster, they aren’t shy about leaving other peoples’ labels on their parts :-)

Doing this meant a lot of cutting and tapping, which is fun for me because I rarely get to do it professionally. To wit:

I had to drill out the pulleys (they’re made for 0.250″ shafts and the shafts in the stands are 7mm) and got all noided about leaving tap magic on them because I was worried about the belts not liking it. This was part of the washing/drying process and won me zero points with my housemates.

So lately I’ve gotten called back into the top-secret toy-prototype world a lot and have not gotten as much research done for Narrat1ve as I might have hoped to.

However, I have tweaked my new video synth about as far as it can go with the current hardware, and got a chance to show it off at the Midwest Experimental Electronics Showcase last Saturday (that link will probably not be about MEES forever).
It looks considerably more badass than it did when I last showed it in New York, although it is still far from ideal. I’ve gotten a lot of what I’ll call “trippiness in the Horizontal range” and now know how and why all of that happens, how color encoding works, how interlacing and sync work, and what audio looks like coded directly into RGB color information. In general I feel pretty confident about the essentially obsolete technology of analog video :-)
I’m excited about plowing through the next revision as soon as I get some time. It should be a lot more badass, and include some frequency multiplication, waveshaping, and the ability to incorporate external video.

I also met some nice folks named Arturo and Sarah whose company likely knows a whole lot more about said osolete video than me, and it turned out that Arturo used to work on the Sandin IP which was among the first artsy fartsy video synths ever made (along with Stephen Beck and Nam June Paik’s stuff) right here in Chicago! Historical Context W00t!

In WTPA news, shipping shipping shipping. The videos and pics from people who’ve successfully built the thing are starting to come in, and I should get them up soon.

EDIT:

Tue May 19 20:32:31 CDT 2009

Whoa. I just found this Linear Technology App Note which is blowing my mind. Any of you interested in analog video should cop that *ish.

Xo, TB

There is some spiritual sense of wholeness, some cosmic teleology that makes me feel thoughtful about posting pictures of a circuit called “Where’s The Party At” when it’s Friday night.

Like if somehow all the drunk, attractive people on Milwaukee Avenue could see the current in these traces they wouldn’t go to a 4am bar, because they would already have been there. Or something. I can’t decide whether this parable is supposed to be more like the two young fish meeting the old fish in the river, or the young bull and the old bull seeing all the cows from the top of the mountain. Some kind of middling-stinky animals appreciating time-and-reality type business is what I suppose I’m going for here.

*Ahem* So:

The next revision of PCBs are in! You’re looking at the Version 0.95 WTPA “barebones” boards. One thing I really like about Advanced Circuits is those sharp (and handy) fluorescent notepads they give you when you order a board. It tickles my hope for nerd-success: I used to really have to hoard them — not so long ago it took Very Serious Consideration before ripping off one of those bright, rare leaves to write “Call Mom” or something. Now I can pretty much paper my walls with them. Feels good. Before you know it I’ll have a cummerbund!

I can already see it’s going to be one of those nights, so down to business: These boards are necessary because they’re the last rev before I order the hundreds of PCBs and many thou of parts I’ll need for the real production release. Hopefully these guys are pretty close to perfect. Parts are already on their way from Digikey and Mouser and should be here next week. I’ve got an OS to re-write in the meantime — I’ve been learning a lot about the GNU Linker for some other projects and as a result my MCU code is getting a lot more pretty looking, and a little more clear (to me anyway) w/r/t how GCC’s optimizer thinks about it. Practically speaking I doubt I’ll have the OS re-written in the next couple weeks: I’ve been nuts making a Playstation version of Beat The Champ (also #8 here) which needs to be done in short order and, and just got a fancy interior design related project which of course ought to be done like yesterday, too. Of course the X-Prize Lunar Lander Challenge is next weekend and I plan to get good and drunk and watch my friends at TrueZer0 put a whoopin’ on the guy that wrote Doom.
Finally, my crappy electronic music project is playing (using WTPA even) next Friday at the Hideout with my old buddies in Parts and Labor.