Microship Serial Crossbar

by Steven K. Roberts
Nomadic Research Labs
Santa Clara, California
April 24, 1996

Oh Yeah… Wanderlust

It’s a strange phenomenon, this technomadic life. The past few days, we’ve had the pleasure of hosting a couple of travelers who independently wandered by and crossed paths here at the lab. Ryan McKenzie is off on a bicycle tour (GreenTHREAD Expedition) around the world, investigating urban communities; Eyal Kattan is an alternative newspaper publisher from Montreal who’s now wandering the Americas in a funky micro-schoolbus… and as I write, is up in the front office with Faun, talking Technomadic Connection business.

All this brings back a wistful melange of images from my own wanderings — 17,000 miles of pedaling and many times that in the Mothership. Throughout the 80’s, I was a professional house guest and diehard yuppie vagabond, staying in different places every few days, deeply familiar with the contents of my packs, comfy in a sleeping bag, and open always to new relationships. If somehow, through happenstance of timing and luck, I indeed became the “high priest of hobos,” as Next Step put it, well, that was secondary to the real motivation. Basically, I was on a quest for romance, freedom, adventure, magical toys, and new frontiers — finding all five in abundance, and in the most unexpected places.

I’m still at it, plugging away at the communications infrastructure of my latest escape pod — but faced with nomadic lab guests I do have to admit that autosensing RS-232 polarity seems rather abstract. All week, I’ve been immersed in CAD files, building low-level network tools, and collecting video cameras… important Microship stuff, to be sure, but circuit boards sure don’t look very nautical sitting there on the bench.

As a sanity recalibration, we hit the water Saturday in a Hunter 31 (monohull sloop) owned by Darryl Lieux of Siliconix. We launched from South Beach Harbor in San Francisco, just south of the Bay Bridge, and had a languid motorsail around Angel Island, at last heeling over and kicking properly into gear on the way back when a mild but steady west wind of 10-15 knots piped up. Oh yeah… I remember… it was good to handle the headsail, take a few fixes for piloting practice, and nosh down on eclairs and champagne. As always, I wanted to keep going: just out the Gate, left at the light, and south for a few thousand miles til we find a hole in an isthmus, then through that and northeast for a while…

<sigh> One o’ these days…

Bellying Up to the SeXBAR

The serial crossbar network is well underway now — but for a temporary hiatus caused by a shortage of 4.3V zeners, the hardware is nailed. I pop-riveted a dense matrix of female DB-9 connectors from Halted onto a substrate of aluminum angle, mounted on standoffs above the SeXBAR board. Tedious, but as always, satisfying in retrospect. The CAD artwork is done in DesignWorks, and I’ve been adding the +/- 5V clamping networks to the “transmit” side — initially with the intent of protecting the 8816 chips against the inevitable RS-232 reverse-polarity connection (which is, as you know, about 50% of the time).

But it occurred to me in the middle of all this that we have the opportunity to do something tres cool here… so I’m playing with a little sensing circuit that lets the Hub, upon any SeXBAR connection command, take a quick look at “pins 2 and 3” of each channel, decide which is transmit, and make the appropriate connections through the matrix. This autopolarity feature offers, at last, the opportunity to think of RS-232 cables as single wires, not statistical gambles involving a host of mutually-incompatible variations. I’ll let you know how it works in practice… once the wiring to the connector array is done, it’s SMOP (Simply a Matter Of Programming). Full schematics in the next issue or so…

Turret Camera Acquisition

Just a quickie on this topic until I actually get it installed, but I *finally* found the color turret camera I’ve been wanting! As you may know, the video turret will be mounted somewhere prominent (like above the cockpit), and will be our primary source of “beauty shots” of surrounding scenery. It carries two cameras, mounted 90 degrees apart: a .05-lux monochrome for IR-illuminated night security, and the color unit I just found.

The source was the venerable Foothill Flea Market, and the vendor was George Martin, who specializes in video cameras and LCD monitors. He sells these Hi-8 camcorder innards for $95, and they include remote-controllable zoom, autofocus, loads of other features, and enough documentation to put them to work. They are .25″ too tall for the existing space between the turret platform and the top of the acrylic cylinder, but I think we can fix that with a bit of aluminum hacking and judicious sanding.

By the way, I also picked up some IR LEDs to begin playing with total darkness applications of the little GBC camera, and was surprised to observe that I can see them as a dull red glow. A filter will be needed… apparently some percentage of the population is sensitive down into that range…

Rigging/glass Update

The most urgent project, of course, is getting the boat rigged and on the water for initial test sails… and that is getting inexorably closer. I’m currently suffering from a severe case of sticker shock: it looks like the glasswork is going to cost about $9K and the rigging about $7K, plus whatever little oh-by-the-ways pop up in the middle of doing the job. The current plan is to haul the boat to North Coast Yachts, a yard in Alameda, and have them do the mast step, bulkhead and mast partner, centerboard and trunk, main hull and ama chainplates, and the stem fitting… then work with Ballenger Spars in Santa Cruz to attach the rig itself. Then we’ll only lack a suit of sails to go for that first test jaunt.

Of course, this is by no means all that’s necessary, even to make the boat structurally sound. There are elements of the 4-bar crossbeam system that need to be replaced, and we still have to deal with such details as ground tackle, winches, and the propulsion system (we’re probably moving the pair of thrusters to the sides of the center hull athwart the aft cabin, by the way — shorter wire runs, less hardware, easier deployment with only two states required, and, most important, minimal likelihood of prop ventilation from rocking back and forth). But getting the rigging done is the one central critical path issue that stands between here and all subsequent packaging.
All of which leads directly to the following topic…

Silicon Valley Tour

For the past few years, my primary business has been speaking — doing the annual 3-month 10,000-mile US tour with BEHEMOTH in the diesel Mothership, giving keynotes and various other talks at trade shows, corporate annual meetings, users groups, companies, and universities. But oddly, I’ve hardly done any here in my own back yard, the epicenter of high-tech industry.

So, while we’re still in Silicon Valley with the bike readily available, I’m starting a series of Friday brown-bags and seminars for local companies. (We have one scheduled at Apple on June 21.) I’ll bring the bike, speak for about an hour including Q&A, and hang around afterwards for informal chat. The topics include the whole technomadic business concept, packaging for mobile systems, nomadic connectivity techniques, tales of adventure, BEHEMOTH and Microship technical details… and anything else related or sufficiently amusing.

If you’re interested in scheduling an event or receiving an abstract and list of previous gigs to pass along to decision-makers, please drop me a line. This is how we’re funding the Microship project, so here’s a way for your company to get involved in a tax-deductible fashion. Direct cash sponsorship is hard for most corporations, since we’re only “non-profit” in a de facto sense… it’s too much paperwork to throw together a 501(c)(3)!

With that, it’s back to the bench! I want to get this new camera mounted and operating under HyperCard control by the next status report…

Gratuitous pun: I wish it had occurred to me last year to name the Fulmar-19 trimaran Mallard… Mallard Fulmar.