Nerdy Texts of Analog and Embedded Systems Wizardry

So, because it isn’t actually in a show yet I can’t talk about what this new dancing stand is for, but it may or may not be capable of beating up Robocop. Suffice it to say, the old gearmotor has been removed from this stand and replaced with a two-pound tank which comes as a separate synchronous motor and gearhead.

This also continues the fascinating if slightly worriesome Spring 2010 trend of my clients viewing me as a one stop for assembly language and abrasives, but things are slow so I’ll take it.

The new gearmotor was similar in size to the old one, but not so similar that it didn’t mean cutting out a big piece of the steel doghouse, making some aluminum mounts to hold the motor, drilling out the timing pulleys to fit the new motor shaft, and putting a detent in said shaft to seat the set screw. I also got my first set of metric taps, so that I could use M4 screws in this guy and the hardware I put in would match the hardware from the factory. This, O art world, is the attention to detail you get when you hire C Programmers to get their thread-cutting on.

Here she is all buttoned up.

Though I have a sneaking feeling Cory doesn’t really care about what the bottom of these things look like, I kinda do. Plus I figure the dust cover, you know, keeps dust out. Plus I had just gotten these really cool carbide burs and I was excited about cutting more holes in stuff.

Perhaps one day, one of these things will have a stepper motor or optical encoder or SOMETHING with silicon in it and everything will come full circle.

More new media art binnis for Cory.
This is basically an installation specific version of that little SBC/datalogger thingy I made. This one hangs out on a silly putting practice stand and plays back controller keypresses on a PS1 when you whack the ball.

To do this, first (well, first you design a weird SBC for new media artists, but) you replace the controller’s MCU (in this case some proprietary TQFP guy) and figure out where his data lines are. I happened to already know that the PS1 basically talks SPI. Some low temp solder and a rework station was used to perform said brain surgery.

The datalines and switch lines are then brought out to my baby, where it handles communication with the PS1. You can then record the game into it, put it on your PC, and do whatever mess you need to with the data.

That golf tee had a set of optical photointerrupters inside it which were originally used to keep track of how hard you hit the ball and how badly you shanked it. I wired one of them to just give me a clean square wave when the ball moved appreciably, since that’s all we needed to know for our game. The code on the “TiVo” had to get changed to account for this, which was no biggie.

Eventually, these things had to get re-built cause Cory got worried that art students would have a few too many PBRs at the openings and eventually whiff and take out one of the external PCBs. I ended up ultimately shock mounting them inside the stand itself. That’s also why Cory is a good client, because he is almost certainly correct. There is a good chance that would have happened before leaving Narrat1ve labs :-)

The dataloggers/TiVos/weird new media art passed the test and I got tooled up to make a bunch. Sometime in the interim, Atmel’s distributors RAN OUT OF STOCK on a lot of their dataflash parts and so there’s a smaller flash chip (the AT45DB161D vs the AT45DB642) which just so happened to be able to fit on that footprint. The tiny, precious Hirose DF series programming connector got replaced by a good-old 6-pin standard-ass 0.1″ header, which made my life easier and really didn’t lose us any board real estate. Above is the pasting of the boards. Yours truly was a human pick and place with these.

I got this fancy Fancourt Flip Rack to theoretically assemble WTPAs, but it got its first shakedown here. It was super handy for soldering in switches and headers for this design.

The assembled panels…

And one of the devices under test. The Cheetah sticker makes it run faster.

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.