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.

So a few weeks ago I met up with my old buddies Limor and Phil at Adafruit Industries and was griping about work being slow, and they were like, design us a kit.

So I did. They wanted a headphone amp which, in their words, “didn’t suck”.
This was really exciting to me! I do a lot of contract work, but I almost NEVER get to do something that’s exclusively analog! Granted, an HPA is not exactly pushing the boundaries of silicon magic in 2010, but I’ll take what I can get. It was a blast. I got to figure out phase margins and characterize ringing and overshoot and make a cable mess (and then worry about the capacitance of it) and just generally get my party on. Plus it was a chance to flex skills in an arena that is full of a lot of crappy designs.

And though the thing is GPL’d,, they did ask me not to go into specifics here or post any schematics or juicy bits UNTIL they have the product out, so until that happens I’m afraid I can’t go into a lot more detail.

Can’t wait to see them lay it out.
Thanks guys!

ALSO — I’d be remiss in not mentioning my friend Shea who had a lot of great advice on this circuit and who has generally forgotten more about audio electronics than I’ll ever know. He re-did the Trident A Range board at Soma Electronic Music Studios when I was back in embedded diapers and let me help re-cap some modules and generally be a solder monkey. I got paid $10 an hour for that and those were still some of the most exciting electronics dollars I ever made.

So one of my clients (Holly Hunt) was gearing up for a big week at ICFF and installed this Solid State Chandelier I designed for them. In nerd terms it’s basically a collection of individual light elements which have a handful of Aluminum core PCBs running these kickass high power LEDs. Nothing complicated, although it had to pass a bunch of UL stuff and required some fiddling with thermal management. And making Aluminum PCBs which I hadn’t done before.

Anyhoo, the chandelier came in to their showroom and was all kinds of screwed up. Turns out it was (mostly) just some solder pads that got lifted in transport, but it was pretty stressful for about a day. I schlepped out to Midtown and fixed it, and spent a lot of time worrying about getting solder (or nerd cooties) on really expensive couches made of goatskin and whatnot.

The pic above is the chandelier hanging precariously on some support chains so I can work on it. All the acrylic has been removed.

Holly Hunt’s ad for the real thing is all up in here.

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.